MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Plant and Cell Physiology' source. Tue, 07 Feb 2012 08:49:01 +0100 http://www.medworm.com/index.php?rid=5595082&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F256%3Frss%3D1 Somaclonal variation is a phenomenon that results in the phenotypic variation of plants regenerated from cell culture. One of the causes of somaclonal variation in rice is the transposition of retrotransposons. However, many aspects of the mechanisms that result in somaclonal variation remain undefined. To detect genome-wide changes in regenerated rice, we analyzed the whole-genome sequences of three plants independently regenerated from cultured cells originating from a single seed stock. Many single-nucleotide polymorphisms (SNPs) and insertions and deletions (indels) were detected in the genomes of the regenerated plants. The transposition of only Tos17 among 43 transposons examined was detected in the regenerated plants. Therefore, the SNPs and indels contribute to the somaclonal varia... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595082 Thu, 12 Jan 2012 05:00:00 +0100 5595082 http://www.medworm.com/index.php?rid=5595081&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F244%3Frss%3D1 Arbuscular mycorrhizas (AMs) are symbiotic interactions established within the roots of most plants by soil fungi belonging to the Glomeromycota. The extensive accommodation of the fungus in the root tissues largely takes place intracellularly, within a specialized interface compartment surrounded by the so-called perifungal membrane, an extension of the host plasmalemma. By combining live confocal imaging of green fluorescent protein (GFP)-tagged proteins and transmission electron microscopy (TEM), we have investigated the mechanisms leading to the biogenesis of this membrane. Our results show that pre-penetration responses and symbiotic interface construction are associated with extensive membrane dynamics. They involve the main components of the exocytotic machinery, with a major partic... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595081 Thu, 12 Jan 2012 05:00:00 +0100 5595081 http://www.medworm.com/index.php?rid=5595080&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F237%3Frss%3D1 Thylakoid membranes contain two types of quinones, benzoquinone (plastoquinone) and naphthoquinone, which are involved in photosynthetic electron transfer. Unlike the benzoquinone, the chemical species of naphthoquinone present (phylloquinone, menaquinone-4 and 5'-monohydroxyphylloquinone) varies depending on the oxygenic photosynthetic organisms. The green alga Chlamydomonas reinhardtii has been used as a model organism to study the function of the naphthoquinone bound to PSI. However, the level of phylloquinone and the presence of other naphthoquinones in this organism remain unknown. In the present study, we found that 5'-monohydroxyphylloquinone is the predominant naphthoquinone in cell and thylakoid extracts based on the retention time during reverse phase HPLC, absorption and mass sp... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595080 Thu, 12 Jan 2012 05:00:00 +0100 5595080 http://www.medworm.com/index.php?rid=5595079&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F225%3Frss%3D1 Legume plants establish a symbiotic association with bacteria called rhizobia, resulting in the formation of nitrogen-fixing root nodules. A Lotus japonicus symbiotic mutant, sen1, forms nodules that are infected by rhizobia but that do not fix nitrogen. Here, we report molecular identification of the causal gene, SEN1, by map-based cloning. The SEN1 gene encodes an integral membrane protein homologous to Glycine max nodulin-21, and also to CCC1, a vacuolar iron/manganese transporter of Saccharomyces cerevisiae, and VIT1, a vacuolar iron transporter of Arabidopsis thaliana. Expression of the SEN1 gene was detected exclusively in nodule-infected cells and increased during nodule development. Nif gene expression as well as the presence of nitrogenase proteins was detected in rhizobia from se... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595079 Thu, 12 Jan 2012 05:00:00 +0100 5595079 http://www.medworm.com/index.php?rid=5595078&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F213%3Frss%3D1 Widespread soil contamination with heavy metals has fostered the need for plant breeders to develop new crops that do not accumulate heavy metals. Metal-transporting transmembrane proteins that transport heavy metals across the plant plasma membrane are key targets for developing these new crops. Oryza sativa heavy metal ATPase 3 (OsHMA3) is known to be a useful gene for limiting cadmium (Cd) accumulation in rice. OsHMA2 is a close homolog of OsHMA3, but the function of OsHMA2 is unknown. To gain insight into the function of OsHMA2, we analyzed three Tos17 insertion mutants. The translocation ratios of zinc (Zn) and Cd were clearly lower in all mutants than in the wild type, suggesting that OsHMA2 is a major transporter of Zn and Cd from roots to shoots. By comparing each allele in the OsH... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595078 Thu, 12 Jan 2012 05:00:00 +0100 5595078 http://www.medworm.com/index.php?rid=5595077&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F204%3Frss%3D1 The western flower thrips (Frankliniella occidentalis) is a polyphagous herbivore that causes serious damage to many agricultural plants. In addition to causing feeding damage, it is also a vector insect that transmits tospoviruses such as Tomato spotted wilt virus (TSWV). We previously reported that thrips feeding on plants induces a jasmonate (JA)-regulated plant defense, which negatively affects both the performance and preference (i.e. host plant attractiveness) of the thrips. The antagonistic interaction between a JA-regulated plant defense and a salicylic acid (SA)-regulated plant defense is well known. Here we report that TSWV infection allows thrips to feed heavily and multiply on Arabidopsis plants. TSWV infection elevated SA contents and induced SA-regulated gene expression in th... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595077 Thu, 12 Jan 2012 05:00:00 +0100 5595077 http://www.medworm.com/index.php?rid=5595076&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F193%3Frss%3D1 CCCH-type zinc finger proteins are important for developmental and environmental responses. However, the precise roles of these proteins in plant stress tolerance are poorly understood. Arabidopsis thaliana Oxidation-related Zinc Finger 2 (AtOZF2) (At4g29190) is an AtOZF1 homolog previously isolated from Arabidopsis, which confers oxidative stress tolerance on plants. The AtOZF2 protein is localized in the plasma membrane, as is AtOZF1. Disruption expression of AtOZF2 led to reduced root length and leaf size. AtOZF2 was implicated to be involved in the ABA and salinity responses. atozf2 antisense lines were more sensitive to ABA and salt stress during the seed germination and cotyledon greening processes. In contrast, AtOZF2-overexpressing plants were more insensitive to ABA and salt stres... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595076 Thu, 12 Jan 2012 05:00:00 +0100 5595076 http://www.medworm.com/index.php?rid=5595075&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F183%3Frss%3D1 Proline accumulation is one of the most common responses of plants to environmental constraints. Thellungiella halophila/salsuginea, a model halophyte, accumulates high levels of proline in response to abiotic stress and in the absence of stress. Recently, lipid signaling pathways have been shown to be involved in the regulation of proline metabolism in Arabidopsis thaliana. Here we investigated the relationship between lipid signaling enzymes and the level of proline in T. salsuginea. Inhibition of phospholipase C (PLC) enzymes by the specific inhibitor U73122 demonstrated that proline accumulation is negatively controlled by PLCs in the absence of stress and under moderate salt stress (200 mM NaCl). The use of 1-butanol to divert some of the phospholipase D (PLD)-derived phosphatidic aci... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595075 Thu, 12 Jan 2012 05:00:00 +0100 5595075 http://www.medworm.com/index.php?rid=5595074&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F173%3Frss%3D1 Panax ginseng is one of the famous medicinal plants. Ginsenosides, a class of tetracyclic triterpene saponins, are mainly responsible for its pharmacological activity. Most ginsenosides are composed of dammarenediol-II aglycone with various sugar moieties. Dammarenediol-II synthase is the first enzyme in the biosynthesis of ginsenosides. Here, we report that transgenic tobacco expressing the P. ginseng dammarenediol-II synthase gene (PgDDS) produced dammarenediol-II, and conferred resistance to Tobacco mosaic virus (TMV). Upon infection with TMV, lesions developed more rapidly in transgenic tobacco plants, and their size was smaller than those of wild-type plants. Transgenic tobacco plants showed a low level of both the viral titer and mRNA accumulation of TMV coat protein (CP) compared wi... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595074 Thu, 12 Jan 2012 05:00:00 +0100 5595074 http://www.medworm.com/index.php?rid=5595073&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F164%3Frss%3D1 Transcriptional regulation of PSI reaction center psaA is one of the important physiological responses to changing environments. We previously reported that the Rrf2-type transcriptional regulator Slr0846 activates transcription of psaA in Synechocystis sp. PCC 6803. In the slr0846 mutant, transcripts from two promoters, P1 and P2, were downshifted and, as a result, a lower Chl content and slower growth were observed. Here, we report spontaneous suppressors which recovered Chl accumulation and photoautotrophic growth. Sequencing of the whole promoter region revealed in some suppressors the same single nucleotide deletion in a 9 bp G stretch (–21 to –29 from the transcriptional start point of P1), which is located between the –35 and –10 elements of the P1 core promo... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595073 Thu, 12 Jan 2012 05:00:00 +0100 5595073 http://www.medworm.com/index.php?rid=5595072&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F154%3Frss%3D1 This study reports a potential strategy to reduce As accumulation in the food chain by expressing heterologous genes in crops. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595072 Thu, 12 Jan 2012 05:00:00 +0100 5595072 http://www.medworm.com/index.php?rid=5595071&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F144%3Frss%3D1 In this study, three rice basic leucine zipper (bZIP) transcription factors (OsbZIP39, OsbZIP50 and OsbZIP60) containing putative transmembrane domains (TMDs) in their C-terminal regions were identified as candidates of the ER stress sensor transducer. One of these proteins, OsbZIP39, was characterized in this study. OsbZIP39 was shown to associate with microsomes as a membrane-integrated protein using the subcellular fractionation method. When the full length and a truncated form of OsbZIP39 without the TMD (OsbZIP39C) was fused to green fluorescent protein (GFP) and transfected into rice protoplasts, the proteins were identified in the cytoplasm and nucleus, respectively. This suggests that OsbZIP39 may be converted into a soluble truncated form by proteolytic cleavage and subsequently t... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595071 Thu, 12 Jan 2012 05:00:00 +0100 5595071 http://www.medworm.com/index.php?rid=5595070&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F135%3Frss%3D1 In this study, we investigated the enzymatic activities of two Arabidopsis thaliana GT43 members, IRX9 (Irregular Xylem9) and IRX14, which have been genetically shown to be non-redundantly involved in the elongation of the xylan backbone. IRX9 and IRX14, alone or simultaneously, were heterologously expressed in tobacco BY2 cells, and microsomes isolated from the transgenic BY2 cells were tested for XylT activity using xylotetraose (Xyl4) as an acceptor and UDP-[14C]xylose as a donor. It was found that although microsomes with expression of IRX9 or IRX14 alone exhibited little incorporation of radiolabeled xylose, a high level of incorporation of radiolabeled xylose onto Xyl4 was conferred by microsomes with co-expression of IRX9 and IRX14. Further analysis using fluorescent anthranilic aci... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595070 Thu, 12 Jan 2012 05:00:00 +0100 5595070 http://www.medworm.com/index.php?rid=5595069&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F125%3Frss%3D1 In this study, we focused on mutants with a Ds insertion in the gene At1g32080 (AtLrgB), which encodes a homolog of the bacterial membrane protein LrgB. Although the detailed function of bacterial LrgB remains unclear, it is speculated that LrgB functions against cell death and lysis in cooperation with LrgA. Reverse transcription–PCR (RT–PCR) and promoter–GUS (β-glucuronidase) analyses showed that AtLrgB is expressed in leaves, stems and flowers, but not in roots. Moreover, its expression in leaves continued until senescence. We used three Ac/Ds-tagged mutants (atlrgB) that showed the same phenotypes. During the continuous observation of seedlings under short-day conditions, we found that the cotyledons and true leaves of the mutant plants during early development s... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595069 Thu, 12 Jan 2012 05:00:00 +0100 5595069 http://www.medworm.com/index.php?rid=5595068&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F118%3Frss%3D1 The emergence of ‘shotgun proteomics’ has paved the way for high-throughput proteome analysis, by which thousands of proteins can be identified simultaneously from complex samples. Although the shotgun approach has the potential to monitor many different post-translational modifications, further technological development is needed to enrich each post-translational ‘modificome’. Large-scale in vivo phosphorylation site mapping, so-called shotgun phosphoproteomics, has become feasible in various organisms, including plants, owing to recent technological breakthroughs. Shotgun phosphoproteomics is not a mature technology, but progress has been rapid. In this review, we highlight the scope and limitations of current methods, and some key technological issues in this fie... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595068 Thu, 12 Jan 2012 05:00:00 +0100 5595068 http://www.medworm.com/index.php?rid=5595067&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F107%3Frss%3D1 Strigolactones are host factors that stimulate seed germination of parasitic plant species such as Striga and Orobanche. This hormone is also important in shoot branching architecture and photomorphogenic development. Strigolactone biosynthetic and signaling mutants in model systems, unlike parasitic plants, only show seed germination phenotypes under limited growth condition. To understand the roles of strigolactones in seed germination, it is necessary to develop a tractable experimental system using model plants such as Arabidopsis. Here, we report that thermoinhibition, which involves exposing seeds to high temperatures, uncovers a clear role for strigolactones in promoting Arabidopsis seed germination. Both strigolactone biosynthetic and signaling mutants showed increased sensitivity ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595067 Thu, 12 Jan 2012 05:00:00 +0100 5595067 http://www.medworm.com/index.php?rid=5595066&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F96%3Frss%3D1 Freshly harvested seeds of Arabidopsis thaliana, Columbia (Col) accession were dormant when imbibed at 25°C in the dark. Their dormancy was alleviated by continuous light during imbibition or by 5 weeks of storage at 20°C (after-ripening). We investigated the possible role of reactive oxygen species (ROS) in the regulation of Col seed dormancy. After 24 h of imbibition at 25°C, non-dormant seeds produced more ROS than dormant seeds, and their catalase activity was lower. In situ ROS localization revealed that germination was associated with an accumulation of superoxide and hydrogen peroxide in the radicle. ROS production was temporally and spatially regulated: ROS were first localized within the cytoplasm upon imbibition of non-dormant seeds, then in the nucleus and finally in... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595066 Thu, 12 Jan 2012 05:00:00 +0100 5595066 http://www.medworm.com/index.php?rid=5595065&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F81%3Frss%3D1 Myrica gale L. (sweet gale) fruit leachate contains myrigalone A (MyA), a rare C-methylated dihydrochalcone and putative allelochemical, which is known to be a phytotoxin impeding seedling growth. We found that MyA inhibited Lepidium sativum L. seed germination in a dose-dependent manner. MyA did not affect testa rupture, but inhibited endosperm rupture and the transition to subsequent seedling growth. MyA inhibited micropylar endosperm cap (CAP) weakening and the increase in the growth potential of the radical/hypocotyl region (RAD) of the embryo, both being key processes required for endosperm rupture. We compared the contents of abscisic acid (ABA) and gibberellins in the tissues and found that the major bioactive forms of gibberellin in L. sativum seed tissues were GA4 and GA6, while G... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595065 Thu, 12 Jan 2012 05:00:00 +0100 5595065 http://www.medworm.com/index.php?rid=5595064&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F64%3Frss%3D1 Grain sorghum [Sorghum bicolor (L) moench] exhibits intraspecific variability for the rate of dormancy release and pre-harvest sprouting behavior. Two inbred lines with contrasting sprouting response were compared: IS9530 (resistant) and RedlandB2 (susceptible). Precocious dormancy release in RedlandB2 is related to an early loss of embryo sensitivity to ABA and higher levels of gibberellins in imbibed grains as compared with IS9530. With the aim of identifying potential regulatory sites for gibberellin metabolism involved in the expression of dormancy in immature grains of both lines, we carried out a time course analysis of transcript levels of putative gibberellin metabolism genes and hormone content (GA1, GA4, GA8 and GA34). A lower embryonic GA4 level in dormant IS9530 was related to ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595064 Thu, 12 Jan 2012 05:00:00 +0100 5595064 http://www.medworm.com/index.php?rid=5595063&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F53%3Frss%3D1 The phytohormone ABA regulates seed germination and stress responses. The identification of clade A protein phosphatase type 2C (PP2C)-interacting proteins PYRABACTIN RESISTANCE 1 (PYR1)/RCAR (REGULATORY COMPONENT OF ABA RECEPTOR) and PYR1-LIKEs (PYLs) as ABA receptors has been a major advance in understanding this process. Here, our aim was to identify additional ABA response loci by suppressor screening of the jasmonate (JA)-insensitive coronatine insensitive 1-16 (coi1-16) mutant using its ABA-hypersensitive phenotype. The identification and genetic characterization of Coi1-16 Resistant to ABA (CRA) loci revealed several unknown and three previously known abi mutants (abi1, abi3 and abi4), thus providing proof-of-concept evidence for this study. The synergistic effect of ABA and JA on s... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595063 Thu, 12 Jan 2012 05:00:00 +0100 5595063 http://www.medworm.com/index.php?rid=5595062&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F38%3Frss%3D1 Seeds in the seed bank experience diurnal cycles of imbibition followed by complete dehydration. These conditions pose a challenge to the regulation of germination. The effect of recurring hydration–dehydration (Hy–Dh) cycles were tested on seeds from four Arabidopsis thaliana accessions [Col-0, Cvi, C24 and Ler]. Diurnal Hy–Dh cycles had a detrimental effect on the germination rate and on the final percentage of germination in Col-0, Cvi and C24 ecotypes, but not in the Ler ecotype, which showed improved vigor following the treatments. Membrane permeability measured by ion conductivity was generally increased following each Hy–Dh cycle and was correlated with changes in the redox status represented by the GSSG/GSH (oxidized/reduced glutathione) ratio. Among the eco... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595062 Thu, 12 Jan 2012 05:00:00 +0100 5595062 http://www.medworm.com/index.php?rid=5595061&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F28%3Frss%3D1 In conclusion, we identified 14 Arabidopsis and nine tomato reference genes. This provides a valuable resource for accurate normalization of gene expression experiments in seed research for two important seed model species. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595061 Thu, 12 Jan 2012 05:00:00 +0100 5595061 http://www.medworm.com/index.php?rid=5595060&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F16%3Frss%3D1 Seed germination is a result of the competition of embryonic growth potential and mechanical constraint by surrounding tissues such as the endosperm. To understand the processes occurring in the endosperm during germination, we analyzed tiling array expression data on dissected endosperm and embryo from 6 and 24 h-imbibed Arabidopsis seeds. The genes preferentially expressed in the endosperm of both 6 and 24 h-imbibed seeds were enriched for those related to cell wall biosynthesis/modifications, flavonol biosynthesis, defense responses and cellular transport. Loss of function of AtXTH31/XTR8, an endosperm-specific gene for a putative xyloglucan endotransglycosylase/hydrolase, led to faster germination. This suggests that AtXTH31/XTR8 is involved in the reinforcement of the cell wall of the... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595060 Thu, 12 Jan 2012 05:00:00 +0100 5595060 http://www.medworm.com/index.php?rid=5595059&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F5%3Frss%3D1 Seeds provide food, feed, fiber and fuel. They are also an important delivery system of genetic information, which is essential for the survival of wild species in ecosystems and the production of agricultural crops. In this review, seed traits and genes that are potentially important for agricultural applications are discussed. Over the long period of crop domestication, seed traits have been modified through intentional or unintentional selections. While most selections have led to seed traits favorable for agricultural consumption, such as larger seeds with higher nutritional value than the wild type, other manipulations in modern breeding sometimes led to negative traits, such as vivipary, precocious germination on the maternal plant or reduced seed vigor, as a side effect during the i... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595059 Thu, 12 Jan 2012 05:00:00 +0100 5595059 http://www.medworm.com/index.php?rid=5595058&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F53%2F1%2F1%3Frss%3D1 (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5595058 Thu, 12 Jan 2012 05:00:00 +0100 5595058 http://www.medworm.com/index.php?rid=5484783&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2225%3Frss%3D1 Cell-penetrating peptides are short cationic peptides with the property of translocating across the plasma membrane and transferring macromolecules otherwise unable to permeate cell membranes. We investigated the potential ability of the protein transduction domain derived from amino acids 47–57 of the human immunodeficiency virus type 1 (HIV-1) TAT (transactivator of transcription) protein to be used as a nanocarrier for the delivery of aequorin, a Ca2+-sensitive photoprotein widely used as a reliable Ca2+ reporter in cell populations. The TAT peptide, either covalently linked to apoaequorin or ionically bound to plasmids encoding differentially targeted aequorin, was supplied to plant suspension-cultured cells. The TAT–aequorin fusion protein was found to be rapidly and effec... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484783 Wed, 07 Dec 2011 05:00:00 +0100 5484783 http://www.medworm.com/index.php?rid=5484782&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2214%3Frss%3D1 In this study, we found that a novel two-component system of photoresponse is involved in the phototactic regulation. Inactivation of slr1212 (pixA), which encodes a photoreceptor histidine kinase, reverted the positive phototaxis of PCC-P to negative phototaxis, and inactivation of the downstream slr1213 (nixB) and slr1214 (nixC), which encode AraC-like transcription factor-type and PatA-type response regulators, respectively, reverted the negative phototaxis of PCC-N to positive phototaxis. Opposite effects of pixA and nixBC disruption implies an unexpected signal transduction pathway in the switching of positive and negative phototaxis. The blue/green-type cyanobacteriochrome GAF domain of PixA was expressed in Synechocystis and phycocyanobilin-producing Escherichia coli. The holoprotei... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484782 Wed, 07 Dec 2011 05:00:00 +0100 5484782 http://www.medworm.com/index.php?rid=5484781&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2200%3Frss%3D1 Cytokinins are a class of phytohormones that play a crucial role in plant growth and development. The gene UGT76C2 encoding cytokinin N-glucosyltransferase of Arabidopsis thaliana has been previously identified. To determine the in planta role of UGT76C2 in cytokinin metabolism and response, we analyzed the phenotypes of its loss-of-function mutant (ugt76c2) and its overexpressors. The accumulation level of the cytokinin N-glucosides was significantly decreased in ugt76c2, but substantially increased in UGT76C2 overexpressors compared with the wild type. When treated with exogenously applied cytokinin, ugt76c2 showed more sensitivity and UGT76C2 overexpressors showed less sensitivity to cytokinin in primary root elongation, lateral root formation, Chl retention and anthocyanin accumulation... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484781 Wed, 07 Dec 2011 05:00:00 +0100 5484781 http://www.medworm.com/index.php?rid=5484780&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2190%3Frss%3D1 Rice seed proteins are known to be a causative antigen in some patients with food allergy, especially cereal allergy, with clinical symptoms such as eczema and dermatitis. The α-amylase/trypsin inhibitors (14–16 kDa), α-globulin (26 kDa) and β-glyoxalase I (33 kDa) are regarded as major potential allergens of rice (Oryza sativa L.) seed based on specific recognition by serum IgE from allergy patients. In order to suppress the production of these major allergens in rice grains, a mutant in the ‘Koshihikari’ background lacking the 26 kDa allergen (GbN-1) was used as a host for RNA silencing. A binary vector harboring two RNA interference (RNAi) gene cassettes for suppression of 14–16 kDa and 33 kDa allergens driven by the 13 kDa and 10 kDa prolamin en... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484780 Wed, 07 Dec 2011 05:00:00 +0100 5484780 http://www.medworm.com/index.php?rid=5484779&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2173%3Frss%3D1 The root accumulation and excretion of riboflavin (Rbfl) and Rbfl derivatives have been studied in the model legume species Medicago truncatula, grown in hydroponics in two different Fe deficiency conditions, with and without CaCO3. Using high resolution mass spectrometry techniques coupled to liquid chromatography, three different flavin derivatives not previously reported in plants, putatively identified as 7-hydroxy-Rbfl, 7α-hydroxy-Rbfl and 7-carboxy-Rbfl, were found along with Rbfl in Fe-deficient M. truncatula roots. In the presence of CaCO3 most of the flavins were accumulated in the roots, whereas in the absence of CaCO3 there was partial export to the nutrient solution. The major flavins in roots and nutrient solution were Rbfl and 7-hydroxy-Rbfl, respectively. Flavins were ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484779 Wed, 07 Dec 2011 05:00:00 +0100 5484779 http://www.medworm.com/index.php?rid=5484778&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2157%3Frss%3D1 Peroxisome proliferation occurs through enlargement, elongation and division of pre-existing peroxisomes. In the Arabidopsis apem mutant, apem3, peroxisomes are dramatically enlarged and reduced in number, revealing a defect in peroxisome proliferation. The APEM3 gene was found to encode peroxisomal membrane protein 38 (PMP38). To examine the relative role of PMP38 during proliferation, a double mutant was constructed consisting of apem3 and the peroxisome division mutant, apem1, in which a defect in dynamin-related protein 3A (DRP3A) results in elongation of peroxisomes. In the double mutant, almost all peroxisomes were predominantly enlarged but not elongated. DRP3A is still able to localize at the peroxisomal membrane on enlarged peroxisomes in the apem3 mutants. PMP38 is revealed to be... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484778 Wed, 07 Dec 2011 05:00:00 +0100 5484778 http://www.medworm.com/index.php?rid=5484777&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2147%3Frss%3D1 In Arabidopsis, the NMD-defective mutants upf1-5 and upf3-1 are characterized by dwarfism, curly leaves and late flowering. These phenotypes are similar to those of mutants showing constitutive pathogenesis-related (PR) gene expression, salicylic acid (SA) accumulation and, subsequently, resistance to pathogens. The disease symptoms of upf1-5 and upf3-1 mutants were observed following infection with the virulent pathogen Pst DC3000 with the aim of determining whether the loss of nonsense-mediated mRNA decay (NMD) is involved in disease resistance. These mutant plants showed not only enhanced resistance to Pst DC3000, but also elevated levels of endogenous SA, PR gene transcripts and WRKY transcripts. UPF1 and UPF3 expression was down-regulated in Pst DC3000-infected Arabidopsis plants, but... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484777 Wed, 07 Dec 2011 05:00:00 +0100 5484777 http://www.medworm.com/index.php?rid=5484776&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2136%3Frss%3D1 In plants, osmotic stress-responsive transcriptional regulation depends mainly on two major classes of cis-acting elements found in the promoter regions of stress-inducible genes: ABA-responsive elements (ABREs) and dehydration-responsive elements (DREs). ABRE has been shown to perceive ABA-mediated osmotic stress signals, whereas DRE is known to be involved in an ABA-independent pathway. Previously, we reported that the transcription factor DRE-BINDING PROTEIN 2A (DREB2A) regulates DRE-mediated transcription of target genes under osmotic stress conditions in Arabidopsis (Arabidopsis thaliana). However, the transcriptional regulation of DREB2A itself remains largely uncharacterized. To elucidate the transcriptional mechanism associated with the DREB2A gene under osmotic stress conditions, ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484776 Wed, 07 Dec 2011 05:00:00 +0100 5484776 http://www.medworm.com/index.php?rid=5484775&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2123%3Frss%3D1 GH3 proteins control auxin homeostasis by inactivating excess auxin as conjugates of amino acids and sugars and thereby controlling cellular bioactive auxin. Since auxin regulates many aspects of plant growth and development, regulated expression of these genes offers a mechanism to control various developmental processes. OsMGH3/OsGH3-8 is expressed abundantly in rice florets and is regulated by two related and redundant transcription factors, OsMADS1 and OsMADS6, but its contribution to flower development is not known. We functionally characterize OsMGH3 by overexpression and knock-down analysis and show a partial overlap in these phenotypes with that of mutants in OsMADS1 and OsMADS6. The overexpression of OsMGH3 during the vegetative phase affects the overall plant architecture, wherea... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484775 Wed, 07 Dec 2011 05:00:00 +0100 5484775 http://www.medworm.com/index.php?rid=5484774&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2115%3Frss%3D1 Cyanobacteria have developed a light-harvesting antenna complex known as the phycobilisome. When cells are starved for nutrients or exposed to high light, the phycobilisome is rapidly degraded (bleaching). It has been suggested that in the cyanobacterium Synechococcus elongatus PCC 7942, the bleaching process is regulated by a two-component histidine kinase, NblS. To clarify the signaling pathway involving NblS, we identified the NblS-interacting response regulators RpaB and SrrA. In vitro assays using recombinant proteins showed that both RpaB and SrrA can receive phosphoryl groups from autophosphorylated NblS; the NblS-interacting protein SipA clearly enhances the phosphotransfer activity from NblS to RpaB and SrrA. In addition, NblS prefers SrrA over RpaB as the phosphotransfer target w... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484774 Wed, 07 Dec 2011 05:00:00 +0100 5484774 http://www.medworm.com/index.php?rid=5484773&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2103%3Frss%3D1 The reversible associations between the light-harvesting complexes (LHCs) and the core complexes of PSI and PSII are essential for the photoacclimation mechanisms in higher plants. Two types of Chls, Chl a and Chl b, both function in light harvesting and are required for the biogenesis of the photosystems. Chl b-less plants have been studied to determine the function of the LHCs because the Chl b deficiency has severe effects specific to the LHCs. Previous studies have shown that the amounts of the LHCs, especially the LHCII trimer, were decreased in the mutants; however, it is still unclear whether Chl b is required for the assembly of the LHCs and for the association of the LHCs with PSI and PSII. Here, to reveal the function of Chl b in the LHCs, we investigated the oligomeric states of... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484773 Wed, 07 Dec 2011 05:00:00 +0100 5484773 http://www.medworm.com/index.php?rid=5484772&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2088%3Frss%3D1 In this study, we show that Arabidopsis phyB is capable of transducing signals with a non-covalently retained chromophore. Substituting the Tyr276 residue of phyB with histidine (Y276H) is known to confer constitutive phyB signaling. PhyB containing both Y276H and C357A substitutions exhibited light-independent biological activity in transgenic Arabidopsis plants in a chromophore-dependent manner. Spectrophotometric analysis showed that the N-terminal domain of phyB containing just the C357A substitution could retain the chromophore non-covalently. The N-terminal domain containing both the Y276H and C357A substitutions interacted with PIF3 in a light-independent but chromophore-dependent fashion in yeast two-hybrid assays. From these results, we conclude that the constitutive phyB signalin... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484772 Wed, 07 Dec 2011 05:00:00 +0100 5484772 http://www.medworm.com/index.php?rid=5484771&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2074%3Frss%3D1 Tobacco culture cells carry out a large-scale degradation of intracellular proteins in order to survive under sucrose starvation conditions. We have previously suggested that this bulk degradation of cellular proteins is performed by autophagy, where autolysosomes formed de novo act as the major lytic compartments. The digestion process in autolysosomes can be retarded by addition of the cysteine protease inhibitor E-64c to the culture medium, resulting in the accumulation of autolysosomes. In the present study, we have investigated several properties of autolysosomes in tobacco cells. Electron microscopy showed that the autolysosomes contain osmiophilic particles, some of which resemble partially degraded mitochondria. It also revealed the presence of two kinds of autolysosome precursor s... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484771 Wed, 07 Dec 2011 05:00:00 +0100 5484771 http://www.medworm.com/index.php?rid=5484770&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2062%3Frss%3D1 Ginseng (Panax ginseng C.A. Meyer) is one of the most popular medicinal herbs and contains pharmacologically active components, ginsenosides, in its roots. Ginsenosides, a class of tetracyclic triterpene saponins, are thought to be synthesized from dammarenediol-II after hydroxylation by the Cyt P450 (CYP) enzyme and then glycosylation by glycosyltransferase (GT). However, no genes encoding the hydroxylation and glycosylation in ginsenoside biosynthesis have been identified. Here, we identify protopanaxadiol synthase, which is a CYP enzyme (CYP716A47), to be involved in the hydroxylation of dammarenediol-II at the C-12 position to yield protopanaxadiol. Nine putative full CYP sequences were isolated from the expressed sequence tags (ESTs) of methyl jasmonate (MeJA)-treated adventitious gin... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484770 Wed, 07 Dec 2011 05:00:00 +0100 5484770 http://www.medworm.com/index.php?rid=5484769&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2050%3Frss%3D1 Triterpenoids are a diverse group of secondary metabolites that are associated with a variety of biological activities. Oleanolic acid, ursolic acid and betulinic acid are common triterpenoids in plants with diverse biological activities, including antifungal, antibacterial, anti-human immunodeficiency virus (HIV) and/or antitumor activities. In the present study, using the gene co-expression analysis tool of Medicago truncatula, we found a strong correlation between CYP716A12 and β-amyrin synthase (bAS), which encodes the enzyme responsible for the initial cyclization of 2,3-oxidosqualene to β-amyrin (the basic structural backbone of most triterpenoid saponins). Through an in vitro assay, we identified CYP716A12 as a β-amyrin 28-oxidase able to modify β-amyrin to olean... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484769 Wed, 07 Dec 2011 05:00:00 +0100 5484769 http://www.medworm.com/index.php?rid=5484768&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2039%3Frss%3D1 The endoplasmic reticulum (ER) is a site for the production of secretory proteins. Plants have developed ER subdomains for protein storage. The ER body is one such structure, which is observed in Brassicaceae plants. ER bodies accumulate in seedlings and roots or in wounded leaves in Arabidopsis. ER bodies contain high amounts of the β-glucosidases PYK10/BGLU23 in seedlings and roots or BGLU18 in wounded tissues. These results suggest that ER bodies are involved in the metabolism of glycoside molecules, presumably to produce repellents against pests and fungi. When Arabidopsis roots are homogenized, PYK10 formed large protein aggregates that include other β-glucosidases (BGLU21 and BGLU22), GDSL lipase-like proteins (GLL22) and cytosolic jacalin-related lectins (PBP1/JAL30, JAL31... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484768 Wed, 07 Dec 2011 05:00:00 +0100 5484768 http://www.medworm.com/index.php?rid=5484767&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F12%2F2017%3Frss%3D1 Omics and bioinformatics are essential to understanding the molecular systems that underlie various plant functions. Recent game-changing sequencing technologies have revitalized sequencing approaches in genomics and have produced opportunities for various emerging analytical applications. Driven by technological advances, several new omics layers such as the interactome, epigenome and hormonome have emerged. Furthermore, in several plant species, the development of omics resources has progressed to address particular biological properties of individual species. Integration of knowledge from omics-based research is an emerging issue as researchers seek to identify significance, gain biological insights and promote translational research. From these perspectives, we provide this review of t... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5484767 Wed, 07 Dec 2011 05:00:00 +0100 5484767 http://www.medworm.com/index.php?rid=5398290&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F2016%3Frss%3D1 (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398290 Wed, 09 Nov 2011 05:00:00 +0100 5398290 http://www.medworm.com/index.php?rid=5398289&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F2006%3Frss%3D1 Glutathione (GSH) is one of the major, soluble, low molecular weight antioxidants, as well as the major non-protein thiol in plant cells. However, the relevance of this molecule could be even greater considering that it can react with nitric oxide (NO) to generate S-nitrosoglutathione (GSNO) which is considered to function as a mobile reservoir of NO bioactivity in plants. Although this NO-derived molecule has an increased physiological and phytopathological relevance in plants cells, its identification and quantification in plant tissues have not be reported so far. Using liquid chromatography–electrospray/mass spectrometry (LC-ES/MS), a method was set up to detect and quantify simultaneously GSNO as well reduced and oxidized glutathione (GSH and GSSG, respectively) in different pep... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398289 Wed, 09 Nov 2011 05:00:00 +0100 5398289 http://www.medworm.com/index.php?rid=5398288&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F1994%3Frss%3D1 To accelerate functional genomic research in tomato, we developed a Micro-Tom TILLING (Targeting Induced Local Lesions In Genomes) platform. DNA pools were constructed from 3,052 ethyl methanesulfonate (EMS) mutant lines treated with 0.5 or 1.0% EMS. The mutation frequency was calculated by screening 10 genes. The 0.5% EMS population had a mild mutation frequency of one mutation per 1,710 kb, whereas the 1.0% EMS population had a frequency of one mutation per 737 kb, a frequency suitable for producing an allelic series of mutations in the target genes. The overall mutation frequency was one mutation per 1,237 kb, which affected an average of three alleles per kilobase screened. To assess whether a Micro-Tom TILLING platform could be used for efficient mutant isolation, six ethylene recepto... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398288 Wed, 09 Nov 2011 05:00:00 +0100 5398288 http://www.medworm.com/index.php?rid=5398287&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F1983%3Frss%3D1 Dark-operative protochrolophyllide (Pchlide) oxidoreductase (DPOR) is a nitrogenase-like enzyme consisting of the two components, L-protein (a ChlL dimer) and NB-protein (a ChlN–ChlB heterotetramer), to catalyze Pchlide reduction in Chl biosynthesis. While nitrogenase is distributed only among certain prokaryotes, the probable structural genes for DPOR are encoded by chloroplast DNA in lower plants. Here we show functional evaluation of DPOR encoded by chloroplast DNA in a moss Physcomitrella patens by the complementation analysis of the cyanobacterium Leptolyngbya boryana and the heterologous reconstitution of the moss L-protein and the cyanobacterial NB-protein. Two shuttle vectors to overexpress chlL and chlN-chlB from P. patens were introduced into the cyanobacterial chlL- and ch... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398287 Wed, 09 Nov 2011 05:00:00 +0100 5398287 http://www.medworm.com/index.php?rid=5398286&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F1973%3Frss%3D1 Chloroplasts are actively anchored at the appropriate intracellular regions to maintain advantageous distribution patterns under specific environmental conditions. Redistribution of chloroplasts is accompanied by their de-anchoring and re-anchoring, respectively, from and to the cortical cytoplasm. In spinach mesophyll cells, high-intensity blue light and Ca2+ treatment induced the disappearance of the meshwork-like array of actin filaments surrounding chloroplasts, which was suppressed by a calmodulin antagonist. Regulatory mechanisms of chloroplast anchoring were investigated using plasma membrane (PM) ghosts, on which the cortical cytoplasm underlying the PM was exposed. Addition of an actin-depolymerizing reagent or >1 µM Ca2+ induced detachment of a substantial number of chlo... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398286 Wed, 09 Nov 2011 05:00:00 +0100 5398286 http://www.medworm.com/index.php?rid=5398285&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F1957%3Frss%3D1 The occurrence of hypoxic conditions in plants not only represents a stress condition but is also associated with the normal development and growth of many organs, leading to adaptive changes in metabolism and growth to prevent internal anoxia. Internal oxygen concentrations decrease inside growing potato tubers, due to their active metabolism and increased resistance to gas diffusion as tubers grow. In the present work, we identified three hypoxia-responsive ERF (StHRE) genes whose expression is regulated by the gradual decrease in oxygen tensions that occur when potato tubers grow larger. Increasing the external oxygen concentration counteracted the modification of StHRE expression during tuber growth, supporting the idea that the actual oxygen levels inside the organs, rather than devel... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398285 Wed, 09 Nov 2011 05:00:00 +0100 5398285 http://www.medworm.com/index.php?rid=5398284&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F1941%3Frss%3D1 The jasmonate receptor COI1 is known to facilitate plant defense responses against necrotrophic pathogens, including the ascomycete Sclerotinia sclerotiorum. However, it is not known to what extent jasmonates contribute to defense nor have COI1-indepenent defense pathways been sufficiently characterized. Here we show that the susceptibility to S. sclerotiorum of the aos mutant, deficient in biosynthesis of jasmonic acid (JA) and its precursor 12-oxophytadienoic acid, was elevated to a level reminiscent of that of hypersusceptible coi1 mutants. In contrast, susceptibility of the JA-deficient opr3 mutant was comparable with that of the wild type. A set of 99 genes responded similarly to infection with S. sclerotiorum in wild-type and coi1 mutant leaves. Expression of this COI1-independent ge... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398284 Wed, 09 Nov 2011 05:00:00 +0100 5398284 http://www.medworm.com/index.php?rid=5398283&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F1931%3Frss%3D1 Recent advances in our understanding of how graminaceous plants take up insoluble forms of iron from the rhizosphere and mobilize them in plant tissues are primarily based on the identification of various transporters that are specific to metal–phytosiderophore (PS) complexes containing mugineic acid and deoxymugineic acid. Barley (Hordeum vulgare L.) yellow stripe 1 (HvYS1) is a metal–PS transporter that preferentially transports Fe(III)–PS compared with other metal complexes. Here, we report the cloning and characterization of HvYSL2, a novel metal–PS transporter encoding gene. HvYSL2 is composed of 702 amino acids with 14 transmembrane domains, which are conserved among this class of transporters, and exhibits 67.3% identity to HvYS1. Electrophysiological experim... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398283 Wed, 09 Nov 2011 05:00:00 +0100 5398283 http://www.medworm.com/index.php?rid=5398282&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F1915%3Frss%3D1 MCA1 is a plasma membrane protein that correlates Ca2+ influx and mechanosensing in Arabidopsis. MCA2 is a paralog of MCA1, and both share 72.7% amino acid sequence identity and several common structural features, including putative transmembrane (TM) segments, an EF hand-like region in the N-terminal half, a coiled-coil motif in the middle and a PLAC8 motif in the C-terminal half. To determine structural regions important for Ca2+ uptake activity, the activity of truncated forms of MCA1 and MCA2 was assessed using yeast expression assays. The N-terminal half of MCA1 with a coiled-coil motif (MCA11–237) did not have Ca2+ uptake activity, while MCA21–237 did. The N-terminal half of MCA1 without the coiled-coil motif (MCA11–185) showed Ca2+ uptake activity, as did MCA21&nda... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398282 Wed, 09 Nov 2011 05:00:00 +0100 5398282 http://www.medworm.com/index.php?rid=5398281&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F1904%3Frss%3D1 This report extends the earlier findings in tobacco and rice to peanut (Arachis hypogaea L.), an important oil crop and protein source. Regulated expression of IPT in peanut significantly improved drought tolerance in both laboratory and field conditions. Transgenic peanut plants maintained higher photosynthetic rates, higher stomatal conductance and higher transpiration than wild-type control plants under reduced irrigation conditions. More importantly, transgenic peanut plants produced significantly higher yields than wild-type control plants in the field, indicating a great potential for the development of crops with improved performance and yield in water-limited areas of the world. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398281 Wed, 09 Nov 2011 05:00:00 +0100 5398281 http://www.medworm.com/index.php?rid=5398280&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F11%2F1873%3Frss%3D1 Strawberry, a small fruit crop of great importance throughout the world, has been considered a model plant system for Rosaceae, and is susceptible to a large variety of phytopathogenic organisms. Most components and mechanisms of the strawberry defense network remain poorly understood. However, from current knowledge, it seems clear that the ability of a strawberry plant to respond efficiently to pathogens relies first on the physiological status of injured tissue (pre-formed mechanisms of defense) and secondly on the general ability to recognize and identify the invaders by surface plant receptors, followed by a broad range of induced mechanisms, which include cell wall reinforcement, production of reactive oxygen species, phytoalexin generation and pathogenesis-related protein accumulati... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5398280 Wed, 09 Nov 2011 05:00:00 +0100 5398280 http://www.medworm.com/index.php?rid=5294824&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1856%3Frss%3D1 The bulk of grass biomass potentially useful for cellulose-based biofuel production is the remains of secondary wall-containing sclerenchymatous fibers. Hence, it is important to uncover the molecular mechanisms underlying the regulation of secondary wall thickening in grass species. So far, little is known about the transcriptional regulatory switches responsible for the activation of the secondary wall biosynthetic program in grass species. Here, we report the roles of a group of rice and maize NAC and MYB transcription factors in the regulation of secondary wall biosynthesis. The rice and maize secondary wall-associated NACs (namely OsSWNs and ZmSWNs) were able to complement the Arabidopsis snd1 nst1 double mutant defective in secondary wall thickening. When overexpressed in Arabidopsis... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294824 Sat, 08 Oct 2011 04:00:00 +0100 5294824 http://www.medworm.com/index.php?rid=5294823&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1844%3Frss%3D1 The actin cytoskeleton is involved in the transport and positioning of Golgi bodies, but the actin-based processes that determine the positioning and motility behavior of Golgi bodies are not well understood. In this work, we have studied the relationship between Golgi body motility behavior and actin organization in intercalary growing root epidermal cells during different developmental stages. We show that in these cells two distinct actin configurations are present, depending on the developmental stage. In small cells of the early root elongation zone, fine filamentous actin (F-actin) occupies the whole cell, including the cortex. In larger cells in the late elongation zone that have almost completed cell elongation, actin filament bundles are interspersed with areas containing this fin... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294823 Sat, 08 Oct 2011 04:00:00 +0100 5294823 http://www.medworm.com/index.php?rid=5294822&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1832%3Frss%3D1 In plant cells, boron (B) occurs predominantly as a borate ester associated with rhamnogalacturonan II (RG-II), but the function of this B–RG-II complex has yet to be investigated. 3-Deoxy-d-manno-2-octulosonic acid (KDO) is a specific component monosaccharide of RG-II. Mutant plants defective in KDO biosynthesis are expected to have altered RG-II structure, and would be useful for studying the physiological function of the B–RG-II complex. Here, we characterized Arabidopsis CTP:KDO cytidylyltransferase (CMP-KDO synthetase; CKS), the enzyme activating KDO as a nucleotide sugar prior to its incorporation into RG-II. Our analyses localized the Arabidopsis CKS protein to mitochondria. The Arabidopsis CKS gene occurs as a single-copy gene in the genome, and we could not obtain cks ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294822 Sat, 08 Oct 2011 04:00:00 +0100 5294822 http://www.medworm.com/index.php?rid=5294821&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1822%3Frss%3D1 In this study, the fates of absorbed light energy in PSII with regard to different TD processes, including qE-TD, were quantitatively estimated by the typical energy allocation models using transgenic rice in which psbS genes were silenced by RNA interference (RNAi). The silencing of psbS genes resulted in a decrease in the light-inducible portion of TD, whereas the allocation of energy to electron transport did not change over a wide range of light intensities. The allocation models indicate that the energy allocated to qE-TD under saturating light is 30–50%. We also showed that a large portion of absorbed light energy is thermally dissipated in manners that are independent of qE. The nature of such dissipations is discussed. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294821 Sat, 08 Oct 2011 04:00:00 +0100 5294821 http://www.medworm.com/index.php?rid=5294820&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1806%3Frss%3D1 Although exogenous ABA-regulated heterophylly has been well documented in multiple plant species, the effect of endogenous ABA and its molecular mechanism remain uncharacterized. In the present study, the effects of endogenous ABA on heterophyllous switching were investigated in two different lily varieties, Lilium formosanum and Lilium oriental hybrid ‘Casa Blanca’. Seedlings of L. formosanum, which have scale-leaf-type growth, displayed low levels of both 9-cis-epoxycarotenoid dioxygenase 3 (LfNCED3) transcripts and ABA, whereas seedlings of L. oriental hybrid ‘Casa Blanca’, which have scale-type growth, displayed high levels of both LoNCED3 transcripts and ABA. Sucrose induced endogenous ABA production in cultured lilies; low ABA induction shows scale-leaf-type g... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294820 Sat, 08 Oct 2011 04:00:00 +0100 5294820 http://www.medworm.com/index.php?rid=5294819&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1786%3Frss%3D1 We have demonstrated that an Arabidopsis serine/arginine rich-like protein, atSR45a, interacts with other splicing factors and its expression is markedly induced by high-light stress, suggesting the involvement of atSR45a in the regulation of stress-responsive alternative splicing. A whole-genome tiling array identified the alternative splicing of genes regulated by atSR45a by comparing gene expression profiles in wild-type and knockout atSR45a (KO-sr45a) plants under high-light stress. The expression levels of genomic regions within 217 genes were significantly altered in the KO-sr45a plants compared with the wild-type plants. Many genes encoded factors involved in signal transduction, cell cycle and DNA processing, protein fate and transcription. A semi-quantitative reverse transcription... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294819 Sat, 08 Oct 2011 04:00:00 +0100 5294819 http://www.medworm.com/index.php?rid=5294818&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1776%3Frss%3D1 GrpE proteins act as co-chaperones for DnaK heat-shock proteins. The dimeric protein unfolds under heat stress conditions, which results in impaired interaction with a DnaK protein. Since interaction of GrpE with DnaK is crucial for the DnaK chaperone activity, GrpE proteins act as a thermosensor in bacteria. Here we have analyzed the thermostability and function of two GrpE homologs of the mesophilic cyanobacterium Synechocystis sp. PCC 6803 and of the thermophilic cyanobacterium Thermosynechococcus elongatus BP1. While in Synechocystis an N-terminal helix pair of the GrpE dimer appears to be the thermosensing domain and mainly mediates GrpE dimerization, the C-terminal four-helix bundle is involved in additional stabilization of the dimeric structure. The four-helix bundle domain has a k... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294818 Sat, 08 Oct 2011 04:00:00 +0100 5294818 http://www.medworm.com/index.php?rid=5294817&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1766%3Frss%3D1 The intracellular accumulation of organic compatible solutes functioning as osmoprotectants, such as polyols, is an important response mechanism of several plants to drought and salinity. In Olea europaea a mannitol transport system (OeMaT1) was previously characterized as a key player in plant response to salinity. In the present study, heterotrophic sink models, such as olive cell suspensions and fruit tissues, and source leaves were used for analytical, biochemical and molecular studies. The kinetic parameters of mannitol dehydrogenase (MTD) determined in cells growing in mannitol, at 25°C and pH 9.0, were as follows: Km, 54.5 mM mannitol; and Vmax, 0.47 µmol h–1 mg–1 protein. The corresponding cDNA was cloned and named OeMTD1. OeMTD1 expression was correlated with... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294817 Sat, 08 Oct 2011 04:00:00 +0100 5294817 http://www.medworm.com/index.php?rid=5294816&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1757%3Frss%3D1 In this report, the kinetics of wound-induced accumulation of 12-hydroxyJA-Ile in plants were examined, and its involvement in the plant wound response is described. Candidate genes for the catabolic enzyme were narrowed down from 272 Arabidopsis Cyt P450 genes using Arabidopsis mutants. The candidate gene was functionally expressed in Pichia pastoris to reveal that CYP94B3 encodes JA-Ile 12-hydroxylase. Expression analyses demonstrate that expression of CYP94B3 is induced by wounding and shows specific activity toward JA-Ile. Plants grown in medium containing JA-Ile show higher sensitivity to JA-Ile in cyp94b3 mutants than in wild-type plants. These results demonstrate that CYP94B3 plays a major regulatory role in controlling the level of JA-Ile in plants. (Source: Plant and Cell Physiolo... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294816 Sat, 08 Oct 2011 04:00:00 +0100 5294816 http://www.medworm.com/index.php?rid=5294815&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1744%3Frss%3D1 Heme oxygenase (HO) catalyzes the oxygen-dependent cleavage of heme to produce biliverdin IXα in phycobilin biosynthesis. In the genome of the cyanobacterium Synechocystis sp. PCC 6803 there are two genes, ho1 (sll1184) and ho2 (sll1875), encoding HO isoforms. Reverse transcription–PCR indicated that ho1 is constitutively expressed, and ho2 is induced under micro-oxic conditions. A mutant lacking ho1 (ho1) failed to grow under aerobic conditions while it did grow at a significantly slower rate than the wild type under anaerobic (micro-oxic) conditions. When micro-oxically grown ho1 was incubated under aerobic conditions, the cells underwent chlorosis with a significant decrease in phycocyanin accompanied by anomalous accumulation of protoporphyrin IX. These results suggested th... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294815 Sat, 08 Oct 2011 04:00:00 +0100 5294815 http://www.medworm.com/index.php?rid=5294814&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1734%3Frss%3D1 Although bisulfite at low concentrations (L-NaHSO3) has been found to increase the cyclic electron transport around PSI (CET), its regulative mechanism remains unknown. In this work, the role of L-NaHSO3 (0.1–500 µM) in NAD(P)H dehydrogenase-dependent CET (the NDH pathway) was investigated. After treatment of tobacco leaves with L-NaHSO3, the NDH pathway, as reflected by a transient post-illumination increase in Chl fluorescence, the dark reduction of P700+ after far-red light and the amount of NDH, was increased after the light–dark–light transition, but was slightly lowered under continuous light. Meanwhile, the linear electron transport (LET) was accelerated by L-NaHSO3 under both the light regimes. Experiments in thylakoids further demonstrated that both LET, mo... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294814 Sat, 08 Oct 2011 04:00:00 +0100 5294814 http://www.medworm.com/index.php?rid=5294813&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1719%3Frss%3D1 Seed germination is a critical developmental period for plant propagation. Information regarding gene expression within this important period is relevant for understanding the main biochemical processes required for successful germination, particularly in maize, one of the most important cereals in the world. The present research focuses on the global microarray analysis of differential gene expression between quiescent and germinated maize embryo stages. This analysis revealed that a large number of mRNAs stored in the quiescent embryonic axes (QEAs) were differentially regulated during germination in the 24 h germinated embryonic axes (GEAs). These genes belong to 14 different functional categories and most of them correspond to metabolic processes, followed by transport, transcription a... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294813 Sat, 08 Oct 2011 04:00:00 +0100 5294813 http://www.medworm.com/index.php?rid=5294812&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F10%2F1709%3Frss%3D1 A wide range of biological processes exhibit circadian rhythm, enabling plants to adapt to the environmental day–night cycle. This rhythm is generated by the so-called ‘circadian clock’. Although a number of genetic approaches have identified >25 clock-associated genes involved in the Arabidopsis clock mechanism, the molecular functions of a large part of these genes are not known. Recent comprehensive studies have revealed the molecular functions of several key clock-associated proteins. This progress has provided mechanistic insights into how key clock-associated proteins are integrated, and may help in understanding the essence of the clock's molecular mechanisms. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5294812 Sat, 08 Oct 2011 04:00:00 +0100 5294812 http://www.medworm.com/index.php?rid=5220800&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1697%3Frss%3D1 The most photosynthetically active leaves of rice seedlings were severely damaged when shoots but not roots were chilled (10°C/25°C, respectively), but no such injury was observed when the whole seedling was chilled (10°C/10°C). To elucidate the mechanisms, we compared the photosynthetic characteristics of the seedlings during the dark chilling treatments. Simultaneous analyses of Chl fluorescence and the change in absorbance of P700 showed that electron transport almost disappeared in both PSII and PSI in the 10°C/25°C leaves, whereas the electron transport rate in PSI in the 10°C/10°C leaves was similar to or higher than that in non-chilled control leaves. Light-induced non-photochemical quenching in PSII was inhibited in the 10°C/25°C leaves, occu... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220800 Tue, 13 Sep 2011 04:00:00 +0100 5220800 http://www.medworm.com/index.php?rid=5220799&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1686%3Frss%3D1 Plant roots play important roles not only in the absorption of water and nutrients, but also in stress tolerance. Previously, we identified RSOsPR10 as a root-specific pathogenesis-related (PR) protein induced by drought and salt treatments in rice. Transcripts and proteins of RSOsPR10 were strongly induced by jasmonate (JA) and the ethylene (ET) precursor 1-aminocyclopropane-1-carboxylic acid (ACC), while salicylic acid (SA) almost completely suppressed these inductions. Immunohistochemical analyses showed that RSOsPR10 strongly accumulated in cortex cells surrounding the vascular system of roots, and this accumulation was also suppressed when SA was applied simultaneously with stress or hormone treatments. In the JA-deficient mutant hebiba, RSOsPR10 expression was up-regulated by NaCl, w... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220799 Tue, 13 Sep 2011 04:00:00 +0100 5220799 http://www.medworm.com/index.php?rid=5220798&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1676%3Frss%3D1 Although charophycean algae form a relevant monophyly with embryophytes and hence occupy a fundamental place in the development of Streptophyta, no tools for genetic transformation in these organisms have been developed. Here we present the first stable nuclear transformation system for the unicellular Zygnematales, the Closterium peracerosum–strigosum–littorale complex (C. psl complex), which is one of the most useful organisms for experimental research on charophycean algae. When a vector, pSA106, containing the dominant selectable marker ble (phleomycin-resistant) gene and a reporter cgfp (Chlamydomonas-adapted green fluorescent protein) gene was introduced into cells via particle bombardment, a total of 19 phleomycin-resistant cells were obtained in the presence of a low co... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220798 Tue, 13 Sep 2011 04:00:00 +0100 5220798 http://www.medworm.com/index.php?rid=5220797&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1665%3Frss%3D1 In this study, we identified a role for HO-1 (encoding heme oxygenase-1) in regulating the response of Chlamydomonas reinhardtii, a unicellular green alga, to mercury (Hg). Transgenic algae overexpressing HO-1 showed high tolerance to Hg exposure, with a 48.2% increase in cell number over the wild type, but accumulated less Hg. Physiological analysis revealed that expression of HO-1 suppressed the Hg-induced generation of reactive oxygen species. We further identified the effect of carbon monoxide (CO), a product of HO-1-mediated heme degradation, on growth and physiological parameters. Interestingly, administration of exogenous CO at non-toxic levels also conferred the tolerance of algae to Hg exposure. The CO-mediated alleviation of Hg toxicity was closely related to the lower accumulati... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220797 Tue, 13 Sep 2011 04:00:00 +0100 5220797 http://www.medworm.com/index.php?rid=5220796&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1657%3Frss%3D1 In this study, we isolated the regulatory particle triple-ATPase (RPT) subunits 2a and 2b, base components of the 19S regulatory particle in the 26S proteasome, as uni-1D-interacting proteins using yeast two-hybrid screening. Genetic studies showed that crossing with the rpt2a mutant reduces the level of uni-1D-induced PR-1 gene expression and suppresses the lethality of uni-1D, by leading to restoration of lost expression of the WUSCHEL gene, which functions to maintain meristem activity, in the shoot apical mersitem of uni-1D. These results suggest that RPT2a is a major interacting partner of uni-1D/UNI, and that the interaction between uni-1D and RPT2a is responsible for activating both morphology and defense signals. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220796 Tue, 13 Sep 2011 04:00:00 +0100 5220796 http://www.medworm.com/index.php?rid=5220795&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1641%3Frss%3D1 This report characterizes a RuvBL in plants and links its activities with its upstream regulator. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220795 Tue, 13 Sep 2011 04:00:00 +0100 5220795 http://www.medworm.com/index.php?rid=5220794&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1628%3Frss%3D1 The 26S proteasome plays fundamental roles in the degradation of short-lived regulatory proteins, thereby controlling diverse cellular processes. In Arabidopsis, the essential RPT2 subunit is encoded by two highly homologous genes: RPT2a and RPT2b. Currently, only RPT2a has been reported to regulate various developmental processes, including the maintenance of the root apical meristem (RAM), although the roles of RPT2a in the RAM are still obscure. Here, we analyzed the cell type-specific requirement for RPT2a. When RPT2a was expressed locally in the rpt2a mutant, pleiotropic defects in the RAM, such as cell death and distorted cellular organization, were rescued differently, suggesting that RPT2a regulates various specific activities, which converge to maintain the RAM. On the other hand,... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220794 Tue, 13 Sep 2011 04:00:00 +0100 5220794 http://www.medworm.com/index.php?rid=5220793&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1613%3Frss%3D1 This study characterized two of the CLAVATA3/endosperm-surrounding region (CLE) genes involved in AON signal transduction. The GmRIC1 and GmRIC2 genes initiated expression solely in the roots at approximately 3 days after inoculation (DAI) with Nod factor-producing rhizobia, corresponding to the time point of AON, and the expression was up-regulated by cytokinins. Levels of GmRIC1 and GmRIC2 gene expression were much higher in the supernodulation mutant, SS2-2, than in wild-type (WT) soybeans during nodule development, even after initiation of nitrogen fixation. At 3 DAI, GmRIC2 was induced in the cells of the pericycle and the outer cortex, which undergo cell division to form nodule primordia and spreads from the central region to the whole nodule as it develops. Overexpression of GmRIC1 ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220793 Tue, 13 Sep 2011 04:00:00 +0100 5220793 http://www.medworm.com/index.php?rid=5220792&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1603%3Frss%3D1 K+ is an essential macronutrient required by plants to complete their life cycle. It fulfills important functions and it is widely used as a fertilizer to increase crop production. Thus, the identification of the systems involved in K+ acquisition by plants has always been a research goal as it may eventually produce molecular tools to enhance crop productivity further. This review is focused on the recent findings on the systems involved in K+ acquisition. From Epstein's pioneering work >40 years ago, K+ uptake was considered to consist of a high- and a low-affinity component. The subsequent molecular approaches identified genes encoding K+ transport systems which could be involved in the first step of K+ uptake at the plant root. Insights into the regulation of these genes and the pro... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220792 Tue, 13 Sep 2011 04:00:00 +0100 5220792 http://www.medworm.com/index.php?rid=5220791&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1583%3Frss%3D1 Plants are generally well adapted to a wide range of environmental conditions. Even though they have notably prospered in our planet, stressful conditions such as salinity, drought and cold or heat, which are increasingly being observed worldwide in the context of the ongoing climate changes, limit their growth and productivity. Behind the remarkable ability of plants to cope with these stresses and still thrive, sophisticated and efficient mechanisms to re-establish and maintain ion and cellular homeostasis are involved. Among the plant arsenal to maintain homeostasis are efficient stress sensing and signaling mechanisms, plant cell detoxification systems, compatible solute and osmoprotectant accumulation and a vital rearrangement of solute transport and compartmentation. The key role of ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220791 Tue, 13 Sep 2011 04:00:00 +0100 5220791 http://www.medworm.com/index.php?rid=5220790&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1569%3Frss%3D1 Intensive research over the last decade has gradually unraveled the mechanisms that underlie how plants react to environmental adversity. Genes involved in many of the essential steps of the stress response have been identified and characterized. In particular, the recent discovery of ABA receptors, progress in understanding the transcriptional and post-transcriptional regulation of stress-responsive gene expression, and studies on hormone interactions under stress have facilitated addressing the molecular basis of how plant cells respond to abiotic stress. Here, we summarize recent research progress on these issues, especially focusing on progress related to the essential and classically important signaling pathways and genes. Despite this wealth of achievements, many challenges remain no... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220790 Tue, 13 Sep 2011 04:00:00 +0100 5220790 http://www.medworm.com/index.php?rid=5220789&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1560%3Frss%3D1 The chloroplast NADH dehydrogenase-like complex (NDH) was first discovered based on its similarity to complex I in respiratory electron transport, and is involved in electron transport from photoproduced stromal reductants such as NADPH and ferredoxin to the intersystem plastoqunone pool. However, a recent study suggested that it is a ferredoxin-dependent plastoquinone reductase rather than an NAD(P)H dehydrogenase. Furthermore, recent advances in subunit analysis of NDH have revealed the presence of a novel hydrophilic subcomplex on the stromal side of the thylakoid membrane, as well as an unexpected lumenal subcomplex. This review discusses these new studies on the structure of NDH, and proposes a unified nomenclature for newly discovered NDH subunits. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220789 Tue, 13 Sep 2011 04:00:00 +0100 5220789 http://www.medworm.com/index.php?rid=5220788&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1546%3Frss%3D1 Pollination is composed of cell–cell communication and complicated signaling cascades that regulate pollen tube growth and guidance toward the ovules for double fertilization, and is critical for successful sexual reproduction. Exploring expression profiles of in vivo grown pollen tubes is important. Nevertheless, it is difficult to obtain accessible pollen tubes for profiling studies in most model plants. By taking advantage of the hollow styles of lily (Lilium longiflorum), in vivo pollen tubes harvested from pollinated styles which had been cut open were used here to study their protein and transcript profiles. Pollination quantitatively and qualitatively altered the total protein composition of elongating pollen tubes. cDNAs generated and amplified from total RNAs of 24 h in vivo... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220788 Tue, 13 Sep 2011 04:00:00 +0100 5220788 http://www.medworm.com/index.php?rid=5220787&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1532%3Frss%3D1 In this study, we generated Oncidium cDNA libraries for six different organs: leaves, pseudobulbs, young inflorescences, inflorescences, flower buds and mature flowers. We utilized 454-pyrosequencing technology to perform high-throughput deep sequencing of the Oncidium transcriptome, yielding >0.9 million reads with an average length of 328 bp, for a total of 301 million bases. De novo assembly of the sequences yielded 50,908 contig sequences with an average length of 493 bp from 796,463 reads and 120,219 singletons. The assembled sequences were annotated using BLAST, and a total of 12,757 and 13,931 unigene transcripts from the Arabidopsis and rice genomes were matched by TBLASTX, respectively. A Gene Ontology (GO) analysis of the annotated Oncidium contigs revealed that the majority o... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220787 Tue, 13 Sep 2011 04:00:00 +0100 5220787 http://www.medworm.com/index.php?rid=5220786&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1515%3Frss%3D1 In this study, we identified 24 APETALA3 (AP3)-like and 13 PISTILLA (PI)-like genes from 11 species of orchids and characterized them into four AP3- and two PI-duplicated homologs. The first duplication event in AP3 homologs occurring in the early evolutionary history of the Orchidaceae gave rise to AP3A and AP3B clades. Further duplication events resulted in four subclades, namely AP3A1, AP3A2, AP3B1 and AP3B2, during the evolution of Orchidaceae. The AP3 paralogous genes were expressed throughout inflorescence and floral bud development. From the in situ hybridization results, we noticed that the transition timings from ubiquitous to constrained expression in floral organs for both clades are different. The transition point of expression of the AP3A clade (clades 3 and 4) was at the late... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220786 Tue, 13 Sep 2011 04:00:00 +0100 5220786 http://www.medworm.com/index.php?rid=5220785&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1501%3Frss%3D1 Being one of the largest families in the angiosperms, Orchidaceae display a great biodiversity resulting from adaptation to diverse habitats. Genomic information on orchids is rather limited, despite their unique and interesting biological features, thus impeding advanced molecular research. Here we report a strategy to integrate sequence outputs of the moth orchid, Phalaenopsis aphrodite, from two high-throughput sequencing platform technologies, Roche 454 and Illumina/Solexa, in order to maximize assembly efficiency. Tissues collected for cDNA library preparation included a wide range of vegetative and reproductive tissues. We also designed an effective workflow for annotation and functional analysis. After assembly and trimming processes, 233,823 unique sequences were obtained. Among th... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220785 Tue, 13 Sep 2011 04:00:00 +0100 5220785 http://www.medworm.com/index.php?rid=5220784&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1487%3Frss%3D1 The cis-prenyltransferase gene LLA66 (Lilium longiflorum anther-66), the first prenyltransferase to be identified in the tapetum and microspores, was selected from a suppression subtractive cDNA library during microspore development in the anther of L. longiflorum. The LLA66 cDNA encodes a polypeptide of 308 amino acids with a calculated molecular mass of 35.7 kDa. Thermal asymmetric interlaced-PCR was employed to obtain the 5'-regulatory region of LLA66. Sequence alignment revealed that the LLA66 protein shares 30–41% identity with cis-prenyltransferases of various broad-spectrum species and is phylogenetically distinct from other monocot cis-prenyltransferases. Based on critical regulatory domains in cis-prenyltransferase, LLA66 was concluded to catalyze the production of long-chai... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220784 Tue, 13 Sep 2011 04:00:00 +0100 5220784 http://www.medworm.com/index.php?rid=5220783&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1467%3Frss%3D1 Orchidaceae constitute one of the largest families of angiosperms. They are one of the most ecological and evolutionary significant plants and have successfully colonized almost every habitat on earth. Because of the significance of plant biology, market needs and the current level of breeding technologies, basic research into orchid biology and the application of biotechnology in the orchid industry are continually endearing scientists to orchids in Taiwan. In this introductory review, we give an overview of the research activities in orchid biology and biotechnology, including the status of genomics, transformation technology, flowering regulation, molecular regulatory mechanisms of floral development, scent production and color presentation. This information will provide a broad scope f... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220783 Tue, 13 Sep 2011 04:00:00 +0100 5220783 http://www.medworm.com/index.php?rid=5220782&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1459%3Frss%3D1 An anther includes sporophytic tissues of three outer cell layers and an innermost layer, the tapetum, which encloses a locule where the gametophytic microspores mature to become pollen. The sporophytic tissues also comprise some vascular cells and specialized cells of the stomium aligning the long anther axis for anther dehiscence. Studies of the anther sporophytic cells, especially the tapetum, have recently expanded from the use of microscopy to molecular biology and transcriptomes. The available sequencing technologies, plus the use of laser microdissection and in silico subtraction, have produced high-quality anther sporophyte transcriptomes of rice, Arabidopsis and maize. These transcriptomes have been used for research discoveries and have potential for future discoveries in diverse... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220782 Tue, 13 Sep 2011 04:00:00 +0100 5220782 http://www.medworm.com/index.php?rid=5220781&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F9%2F1455%3Frss%3D1 (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5220781 Tue, 13 Sep 2011 04:00:00 +0100 5220781 http://www.medworm.com/index.php?rid=5118310&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1443%3Frss%3D1 In this study, we devised an Arabidopsis cell-free extract (ACE) to be used for in vitro translation studies. Protoplasts were prepared from callus cultures derived from Arabidopsis seedlings, and cell-free extracts were prepared after evacuolation of the protoplasts by Percoll gradient centrifugation. The new ACE system exhibits translation activity comparable with that of the wheat germ extract system. We demonstrated that ACE prepared from the 5'–3' exoribonuclease-deficient mutant of Arabidopsis, xrn4-5, exhibited increased stability of an uncapped mRNA as compared with that from wild-type Arabidopsis. We applied the ACE system to study post-transcriptional regulation of AtCGS1. AtCGS1 codes for cystathionine -synthase (CGS) that catalyzes the first committed step of methionine a... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118310 Mon, 08 Aug 2011 23:00:00 +0100 5118310 http://www.medworm.com/index.php?rid=5118309&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1433%3Frss%3D1 Nickel (Ni) is an essential nutrient for plants, but excessive amounts can be toxic. Ni competes with iron (Fe) in vivo, raising the possibility that Ni is competitively taken up via the Fe uptake system in plants. Here, we show evidence that AtIRT1, the primary Fe2+ uptake transporter in the root, mediates Ni accumulation in Arabidopsis thaliana. In hydroponic cultures, excess Ni exposure increased Fe accumulation and the relative transcription level of AtIRT1 in roots, indicating that excess Ni induces AtIRT1 expression in roots. An Fe-deficient treatment increased Ni accumulation in plants, suggesting that excess Ni was absorbed via the Fe uptake system, which was induced by Fe starvation. Moreover, Ni accumulation under Fe-deficient conditions was markedly lower in AtIRT1-defective mut... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118309 Mon, 08 Aug 2011 23:00:00 +0100 5118309 http://www.medworm.com/index.php?rid=5118308&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1422%3Frss%3D1 The phototropin (phot)-dependent intracellular relocation of chloroplasts is a ubiquitous phenomenon in plants. We have previously revealed the involvement of a short cp-actin (chloroplast actin) filament-based mechanism in this movement. Here, the reorganization of cp-actin filaments during the avoidance movement of chloroplasts was analyzed in higher time resolution under blue GFP (green fluorescent protein) excitation light in an actin filament-visualized line of Arabidopsis thaliana. Under standard background red light of 89 µmol m–2 s–1, cp-actin filaments transiently disappeared at approximately 30 s and reappeared in a biased configuration on chloroplasts approximately 70 s after blue excitation light irradiation. The timing of biased cp-actin reappearance was dela... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118308 Mon, 08 Aug 2011 23:00:00 +0100 5118308 http://www.medworm.com/index.php?rid=5118307&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1401%3Frss%3D1 In conclusion, our results suggest that a switch of the metabolic fate of hairy roots in response to MeJA could cause an increase in the accumulation of secondary metabolites. This is likely to have important consequences in the production of specific alkaloids important for the pharmaceutical industry. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118307 Mon, 08 Aug 2011 23:00:00 +0100 5118307 http://www.medworm.com/index.php?rid=5118306&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1389%3Frss%3D1 Tocopherols are antioxidants found in chloroplasts of leaves, and it is a matter of current debate whether or not they can affect signaling and gene expression in plant cells. For insight into the possible effects of altered tocopherol composition in chloroplasts on gene expression in the nucleus, the expression of ethylene biosynthesis, perception and signaling genes was investigated in vte1 and vte4 Arabidopsis thaliana mutants, which are impaired in tocopherol (vitamin E) biosynthesis. Changes in gene expression were measured in plants exposed to either salt or water stress, and in young and mature leaves of vte1 and vte4 mutants, which lack tocopherol cyclase and -tocopherol methyltransferase, respectively. While transcript levels of ethylene signaling genes in the vte1 mutant and the ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118306 Mon, 08 Aug 2011 23:00:00 +0100 5118306 http://www.medworm.com/index.php?rid=5118305&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1376%3Frss%3D1 The EMBRYONIC FLOWER (EMF) 1 gene has been shown to be necessary for maintenance of vegetative development. To investigate the molecular mechanism of EMF1-mediated plant development, we screened EMF1-interacting proteins and identified 11 candidate proteins using the yeast two-hybrid system. Among the candidate genes, three EMF1-Interacting Protein (EIP) genes, EIP1, EIP6 and EIP9, are predicted to encode a WNK (with-no-lysine) kinase, a B-box zinc-finger protein and a DnaJ-domain protein, respectively. The expression patterns of EIP1, EIP6 and EIP9 were similar to that of EMF1, and EMF1–EIP1, EMF1–EIP6 and EMF1–EIP9 heterodimers were localized in the nucleus. In addition, eip1, eip6 and eip9 mutants flowered early and showed increased expression of flowering-time and flo... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118305 Mon, 08 Aug 2011 23:00:00 +0100 5118305 http://www.medworm.com/index.php?rid=5118304&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1365%3Frss%3D1 The stomatal complex of Zea mays is composed of two pore-forming guard cells and two adjacent subsidiary cells. For stomatal movement, potassium ions and anions are thought to shuttle between these two cell types. As potential cation transport pathways, K+-selective channels have already been identified and characterized in subsidiary cells and guard cells. However, so far the nature and regulation of anion channels in these cell types have remained unclear. In order to bridge this gap, we performed patch–clamp experiments with subsidiary cell and guard cell protoplasts. Voltage-independent anion channels were identified in both cell types which, surprisingly, exhibited different, cell-type specific dependencies on cytosolic Ca2+ and pH. After impaling subsidiary cells of intact maiz... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118304 Mon, 08 Aug 2011 23:00:00 +0100 5118304 http://www.medworm.com/index.php?rid=5118303&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1354%3Frss%3D1 In this study, we report a novel function of TDIF and CLE42. We found by the GUS (β-glucuronidase) reporter gene assay that while CLE41 and CLE44 are expressed preferentially in vascular bundles, CLE42 is expressed strongly in the shoot apical meristem (SAM) and axillary meristems. Overexpression of CLE42 and CLE41 enhanced axillary bud formation in the leaf and cotyledon axils. Before floral transition, the emergence of axillary buds in these plants occurred in an acropetal order. Exogenous supply of either TDIF or CLE42 peptide to the wild type induced similar excess bud emergence. In vascular bundles, the TDIF RECEPTOR (TDR) acts as the main receptor for TDIF. The axillary bud emergence of tdr mutants was little affected by either of the peptides. It was confirmed by scanning elect... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118303 Mon, 08 Aug 2011 23:00:00 +0100 5118303 http://www.medworm.com/index.php?rid=5118302&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1340%3Frss%3D1 Polarity along the adaxial–abaxial axis of the leaf is essential for leaf development and morphogenesis. One of the genes that encodes a putative transcription factor regulating adaxial–abaxial polarity, FILAMENTOUS FLOWER (FIL), is expressed in the abaxial region of the leaf primordia. However, the molecular mechanisms controlling the polarized expression of FIL remain unclear. Here, we analyzed an enlarged fil expression domain1 (enf1) mutant of Arabidopsis, which forms both abaxialized leaves and adaxialized leaves. The ENF1 gene encodes SUCCINIC SEMIALDEHYDE DEHYDROGENASE (SSADH), which catalyzes the conversion of succinic semialdehyde (SSA) to succinate. The enf1 phenotype was suppressed by an additional mutation in GAMMA-AMINOBUTYRIC ACID AMINOTRANSFERASE1 (GABAT1), which... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118302 Mon, 08 Aug 2011 23:00:00 +0100 5118302 http://www.medworm.com/index.php?rid=5118301&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1330%3Frss%3D1 Flowering plants produce multicellular gametophytes through an elaborate regulation of gametogenesis. During female and male gametogenesis in Arabidopsis thaliana, sporogenous cells differentiate and undergo meiosis to produce megaspores and microspores, which in turn go through mitosis to develop into multicellular gametophytes. Here we report that the Arabidopsis spliceosomal protein, SPLICEOSOME-ASSOCIATED PROTEIN 130 (AtSAP130), is required for proper reproduction. AtSAP130 is encoded by two genes, AtSAP130a and AtSAP130b. Plants with reduced expression of the AtSAP130 genes, induced by RNA interference, showed a defect in fertilization. Besides functional impairment observed in the female reproductive organs, analysis focusing on pollen development revealed defects in the transition f... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118301 Mon, 08 Aug 2011 23:00:00 +0100 5118301 http://www.medworm.com/index.php?rid=5118300&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1315%3Frss%3D1 The plant circadian clock generates rhythms with a period close to 24 h, and it controls a wide variety of physiological and developmental events. Among clock-controlled developmental events, the best characterized is the photoperiodic control of flowering time, which is mediated through the CONSTANS (CO)–FLOWERING LOCUS T (FT) pathway in Arabidopsis thaliana. The clock also regulates the diurnal plant growth including the elongation of hypocotyls in a short day (SDs)-specific manner. In this mechanism, phytochromes (mainly phyB) and the PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and PIF5, encoding phytochrome-interacting basic helix–loop–helix (bHLH) transcription factors, play crucial roles. The time of day-specific and photoperiodic control of hypocotyl elongation is best ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118300 Mon, 08 Aug 2011 23:00:00 +0100 5118300 http://www.medworm.com/index.php?rid=5118299&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1302%3Frss%3D1 The unicellular green alga Chlamydomonas reinhardtii can acclimate to a wide range of CO2 concentrations through the regulation of a CO2-concentrating mechanism (CCM). By proteomic analysis, here we identified the proteins which were specifically accumulated under high-CO2 conditions in a cell wall-less strain of C. reinhardtii which release their extracellular matrix into the medium. When the CO2 concentration was elevated from the ambient air level to 3% during culture, the algal growth rate increased 1.5-fold and the composition of extracellular proteins, but not intracellular soluble and insoluble proteins, clearly changed. Proteomic analysis data showed that the levels of 22 of 129 extracellular proteins increased for 1 and 3 d and such multiple high-CO2-inducible proteins include gam... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118299 Mon, 08 Aug 2011 23:00:00 +0100 5118299 http://www.medworm.com/index.php?rid=5118298&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1289%3Frss%3D1 Xylan is one of the major polysaccharides in cellulosic biomass, and understanding the mechanisms underlying xylan biosynthesis will potentially help us design strategies to produce cellulosic biomass better suited for biofuel production. Although a number of genes have been shown to be essential for xylan biosynthesis, genes involved in the acetylation of xylan have not yet been identified. Here, we report the comprehensive genetic and functional studies of four Arabidopsis REDUCED WALL ACETYLATION (RWA) genes and demonstrate their involvement in the acetylation of xylan during secondary wall biosynthesis. It was found that the RWA genes were expressed in cells undergoing secondary wall thickening and their expression was regulated by SND1, a transcriptional master switch of secondary wal... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118298 Mon, 08 Aug 2011 23:00:00 +0100 5118298 http://www.medworm.com/index.php?rid=5118297&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1274%3Frss%3D1 We investigated the identity and distribution of cortical domains, stained by the endocytic marker FM 1-43, in branchlet internodal cells of the characean green algae Chara corallina and Chara braunii. Co-labeling with NBD C6-sphingomyelin, a plasma membrane dye, which is not internalized, confirmed their location in the plasma membrane, and co-labelling with the fluorescent pH indicator Lysotracker red indicated an acidic environment. The plasma membrane domains co-localized with the distribution of an antibody against a proton-translocating ATPase, and electron microscopic data confirmed their identity with elaborate plasma membrane invaginations known as charasomes. The average size and the distribution pattern of charasomes correlated with the pH banding pattern of the cell. Charasomes... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118297 Mon, 08 Aug 2011 23:00:00 +0100 5118297 http://www.medworm.com/index.php?rid=5118296&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F8%2F1259%3Frss%3D1 We describe here the enhancer-of-asymmetric-leaves-two1 (east1) mutation, which caused the formation of filamentous leaves with abaxialized epidermis on the as2-1 background. Levels of transcripts of class 1 KNOX and abaxial-determinant genes were markedly higher in as2-1 east1-1 mutant plants than in the wild-type and corresponding single-mutant plants. EAST1 encodes the histone acetyltransferase ELONGATA3 (ELO3), a component of the Elongator complex. Genetic analysis, using mutations in genes involved in the biogenesis of a trans-acting small interfering RNA (ta-siRNA), revealed that ELO3 mediated establishment of leaf polarity independently of AS2 and the ta-siRNA-related pathway. Treatment with an inhibitor of histone deacetylases (HDACs) caused additive polarity defects in as2-1 east1... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5118296 Mon, 08 Aug 2011 23:00:00 +0100 5118296 http://www.medworm.com/index.php?rid=5019014&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1249%3Frss%3D1 Oryza sativa is widely used as a model organism for many aspects of research in monocots and cereals. However, it has certain disadvantages as a model species compared with Arabidopsis thaliana, the eudicot species most widely used in plant sciences: first, it has a long cultivation time; and second, it requires considerably more space for growth. Here, we introduce a biotron breeding system, which allows rapid and reliable rice cultivation using a well-equipped artificial environmental chamber. This system involves use of regulation of CO2 levels, removal of tillers and embryo rescue to overcome the disadvantages of rice cultivation. The rice cultivars Nipponbare, Koshihikari, Taichung 65 and Kasalath all showed vigorous growth and sufficient seed production in the biotron breeding system... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019014 Fri, 08 Jul 2011 23:00:00 +0100 5019014 http://www.medworm.com/index.php?rid=5019013&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1238%3Frss%3D1 Blue light (BL) receptor phototropins activate the plasma membrane H+-ATPase in guard cells through phosphorylation of a penultimate threonine and subsequent binding of the 14-3-3 protein to the phosphorylated C-terminus of H+-ATPase, mediating stomatal opening. To date, detection of the phosphorylation level of the guard cell H+-ATPase has been performed biochemically using guard cell protoplasts (GCPs). However, preparation of GCPs from Arabidopsis for this purpose requires >5,000 rosette leaves and takes >8 h. Here, we show that BL-induced phosphorylation of guard cell H+-ATPase is detected in the epidermis from a single Arabidopsis rosette leaf via an immunohistochemical method using a specific antibody against the phosphorylated penultimate threonine of H+-ATPase. BL-induced pho... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019013 Fri, 08 Jul 2011 23:00:00 +0100 5019013 http://www.medworm.com/index.php?rid=5019012&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1222%3Frss%3D1 The branched respiratory electron transport chain of plants contains a non-phosphorylating alternative pathway consisting of type II NAD(P)H dehydrogenases on both sides of the inner membrane linked through the ubiquinone pool to an alternative oxidase (AOX). T-DNA and RNA interference (RNAi) were used to reduce gene expression to characterize the external NAD(P)H dehydrogenase NDB4 in Arabidopsis. The ndb4 lines showed different levels of suppression of NDB4 protein, leading to increases in NBD2 and AOX1a mRNA and protein levels in all lines. These changes were associated with lower reactive oxygen species formation and an altered phenotype, including changes in growth rate, root : shoot ratios and leaf area. The general growth pattern for the ndb4 mutants was decreased leaf area early in... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019012 Fri, 08 Jul 2011 23:00:00 +0100 5019012 http://www.medworm.com/index.php?rid=5019011&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1211%3Frss%3D1 Plant aerial parts are differentiated from stem cells that are located in the shoot apical meristem (SAM). CLAVATA3 (CLV3)–CLV1 is a well-known ligand–receptor pair, which functions in SAM maintenance. In Lotus japonicus, HYPERNODULATION ABERRANT ROOT FORMATION1 (HAR1) shows the highest similarity with CLV1 of all Arabidopsis receptor-like kinases (RLKs). However, HAR1 functions in the systemic regulation of root nodule development, but does not appear to function in SAM maintenance. Therefore, the gene that is responsible for SAM maintenance in L. japonicus is largely unknown. Here, we identified the L. japonicus CLV3-like (LjCLV3) gene as a counterpart of AtCLV3 and performed expression and functional analysis. LjCLV3 transcripts were detected in the central region of the sho... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019011 Fri, 08 Jul 2011 23:00:00 +0100 5019011 http://www.medworm.com/index.php?rid=5019010&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1204%3Frss%3D1 This study characterized the selenite uptake mechanism using 75Se as a tracer. Kinetic analysis of selenite uptake showed the involvement of both active and passive transport processes. The active transport was suppressed by 0.5 mM vanadate, a membrane-permeable inhibitor of H+-ATPase, at pH 8.3. When the pH was lowered from 8.3 to 5.3, the selenite uptake activity greatly increased, even in the presence of vanadate, suggesting that the H+ concentration gradient may be a motive force for selenite transport. [75Se]Selenite uptake at selenite-limiting concentrations was hardly affected by selenate, sulfate and sulfite, even at 100 µM. In contrast, 3 µM orthophosphate increased the Km 5-fold. These data showed that HSeO3–, a dominant selenite species at acidic pH, is the act... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019010 Fri, 08 Jul 2011 23:00:00 +0100 5019010 http://www.medworm.com/index.php?rid=5019009&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1193%3Frss%3D1 Interactions between β-carotene (β-C) and Chl a turnover were investigated in relation to photoinhibition and D1 protein turnover in mature leaves of Arabidopsis (Arabidopsis thaliana) by 14CO2 pulse–chase labeling. Following a 2 h treatment of leaves with water, lincomycin (Linco; an inhibitor of chloroplast protein synthesis) or norflurazon (NF; an inhibitor of carotenoid biosynthesis at phytoene desaturation) in the dark, 14CO2 was applied to the leaves for 30 min under control light (CL; 130 µmol photons m–2 s–1) conditions, followed by exposure to either CL or high light (HL; 1,100 µmol photons m–2 s–1) in ambient CO2 for up to 6 h. Under both light conditions, 14C incorporation was strongly decreased for Chl a and moderately suppres... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019009 Fri, 08 Jul 2011 23:00:00 +0100 5019009 http://www.medworm.com/index.php?rid=5019008&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1177%3Frss%3D1 The actin cytoskeleton plays a crucial role in many aspects of plant cell development. During male gametophyte development, the actin arrays are conspicuously remodeled both during pollen maturation in the anther and after pollen hydration on the receptive stigma and pollen tube elongation. Remodeling of actin arrays results from the highly orchestrated activities of numerous actin binding proteins (ABPs). A key player in actin remodeling is the actin depolymerizing factor (ADF), which increases actin filament treadmilling rates. We prepared fluorescent protein fusions of two Arabidopsis pollen-specific ADFs, ADF7 and ADF10. We monitored the expression and subcellular localization of these proteins during male gametophyte development, pollen germination and pollen tube growth. ADF7 and ADF... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019008 Fri, 08 Jul 2011 23:00:00 +0100 5019008 http://www.medworm.com/index.php?rid=5019007&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1162%3Frss%3D1 It is widely considered that ADP-glucose pyrophosphorylase (AGP) is the sole source of ADP-glucose linked to bacterial glycogen and plant starch biosynthesis. Genetic evidence that bacterial glycogen biosynthesis occurs solely by the AGP pathway has been obtained with glgC– AGP mutants. However, recent studies have shown that (i) these mutants can accumulate high levels of ADP-glucose and glycogen, and (ii) there are sources other than GlgC, of ADP-glucose linked to glycogen biosynthesis. In Arabidopsis, evidence showing that starch biosynthesis occurs solely by the AGP pathway has been obtained with the starchless adg1-1 and aps1 AGP mutants. However, mounting evidence has been compiled previewing the occurrence of more than one important ADP-glucose source in plants. In attempting ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019007 Fri, 08 Jul 2011 23:00:00 +0100 5019007 http://www.medworm.com/index.php?rid=5019006&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1153%3Frss%3D1 Glutathione-dependent detoxification is a key pathway that allows plants to efficiently remove toxic compounds like heavy metals or electrophilic xenobiotics. Under persistent exposure to toxins plants need to respond to continuous demand with efficient synthesis of glutathione (GSH) and ideally fast and efficient removal of potentially toxic glutathione S-conjugates. With the aim of studying the respective degradation pathway in Physcomitrella patens we initially characterized fluorescence labeling of protonema cultures with GSH-specific xenobiotic monochlorobimane (MCB). Incubation of protonema with 200 µM MCB for 24 h resulted in a steady increase of total bimane label, which was not confined to glutathione S-bimane (GS-B), but predominantly present in -glutamylcysteine S-bimane (... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019006 Fri, 08 Jul 2011 23:00:00 +0100 5019006 http://www.medworm.com/index.php?rid=5019005&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1142%3Frss%3D1 In this study, we investigate the dynamic remodeling of vacuolar compartments during Arabidopsis seed germination using immunocytochemistry with antibodies against tonoplast intrinsic protein (TIP) isoforms as well as proteins involved in nutrient mobilization and vacuolar acidification. Our results confirm the existence of a lytic compartment embedded in the protein storage vacuole of dry seeds, decorated by -TIP, the vacuolar proton pumping pyrophosphatase (V-PPase) and the metal transporter NRAMP4. They further indicate that this compartment disappears after stratification. It is then replaced by a newly formed lytic compartment, labeled by -TIP and V-PPase but not AtNRAMP4, which occupies a larger volume as germination progresses. Altogether, our results indicate the successive occurre... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019005 Fri, 08 Jul 2011 23:00:00 +0100 5019005 http://www.medworm.com/index.php?rid=5019004&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F7%2F1131%3Frss%3D1 We report here the isolation of a novel basic helix–loop–helix protein, CjbHLH1, from IQA-producing Coptis japonica. A BLAST search indicated that CjbHLH1 homologs were only found in plant species that produce IQAs. Transient RNA interference (RNAi) and overexpression of CjbHLH1 in C. japonica protoplasts revealed the activity of CjbHLH1 in transcription of IQA biosynthetic genes, and little activity in the transcription of genes involved in primary metabolism or the stress response. A chromatin immunoprecipitation experiment using CjbHLH1-specific antibodies revealed the direct interaction of CjbHLH1 with promoter sequences of IQA biosynthetic genes in vivo. We discuss the unique role of CjbHLH1 in IQA biosynthesis. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=5019004 Fri, 08 Jul 2011 23:00:00 +0100 5019004 http://www.medworm.com/index.php?rid=4920888&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1117%3Frss%3D1 In Arabidopsis, the MYC2-family basic helix–loop–helix transcription factors mediate transcriptional regulation of jasmonate-responsive genes, and their transcriptional activities are suppressed by physical interactions with jasmonate-ZIM domain (JAZ) proteins. Jasmonate-inducible nicotine formation in Nicotiana plants has been shown to be suppressed by tobacco JAZ proteins, and be regulated by both MYC2-related and NIC2-locus ethylene response factor (ERF) transcription factors. We here show that tobacco MYC2 (NtMYC2) recognizes the G-box sequences, 5'-CAC(G/A)T(G/T)-3', found in the proximal promoter regions of several nicotine biosynthesis genes, including Putrescine N-Methyltransferase 2 (PMT2) and Quinolinate Phosphoribosyltransferase 2 (QPT2). Transient transactivation as... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920888 Wed, 08 Jun 2011 23:00:00 +0100 4920888 http://www.medworm.com/index.php?rid=4920887&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1107%3Frss%3D1 The effect of a hypoxic pre-treatment (HPT) on improving tolerance to prolonged anoxia conditions in two contrasting Vitis species (V. riparia, anoxia tolerant; V. rupestris, anoxia sensitive) was evaluated. The energy economy of root cells was studied by measuring heat production, the activity of pyruvate decarboxylase (PDC) and alcohol dehdrogenase (ADH), ethanol and ATP production, and K+ fluxes. The results showed that HPT is an effective tool in order to maintain a sustainable metabolic performance in both the species under anoxia conditions, especially in sensitive species such as V. rupestris. Our results showed that the improved tolerance was mainly driven by: (i) an enhanced activity of key enzymes in alcohol fermentation (ADC and PDC); (ii) the capability to maintain a higher lev... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920887 Wed, 08 Jun 2011 23:00:00 +0100 4920887 http://www.medworm.com/index.php?rid=4920886&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1095%3Frss%3D1 In higher plants, many extracellular proteins are involved in developmental processes, including cell–cell signaling and cell wall construction. Xylogen is an extracellular arabinogalactan protein (AGP) isolated from Zinnia elegans xylogenic culture medium, which promotes xylem cell differentiation. Xylogen has a unique structure, containing a non-specific lipid transfer protein (nsLTP) domain and AGP domains. We searched for xylogen-type genes in the genomes of land plants, including Arabidopsis thaliana, to further our knowledge of xylogen-type genes as functional extracellular proteins in plants. We found that many xylogen-type genes, including 13 Arabidopsis genes, comprise a gene family in land plants, including Populus trichocarpa, Vitis vinifera, Lotus japonicus, Oryza sativa,... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920886 Wed, 08 Jun 2011 23:00:00 +0100 4920886 http://www.medworm.com/index.php?rid=4920885&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1083%3Frss%3D1 Although flowering time is often associated with plant size, little is known about how flowering time genes affect plant architecture. We grew four rice lines having different flowering time genotypes (hd1 ehd1, hd1 Ehd1, Hd1 ehd1 and Hd1 Ehd1) under distinct photoperiod conditions. By using genotype–treatment combinations that resulted in similar flowering times, we were able to compare the effects of flowering time genes on traits related to plant architecture. The results revealed that the combination of Heading-date 1 (Hd1) and Early heading date 1 (Ehd1) can reduce the number of primary branches in a panicle, resulting in smaller spikelet numbers per panicle; this occurs independently of the control of flowering time. In addition, expression of the Hd3a and Rice Flowering-locus ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920885 Wed, 08 Jun 2011 23:00:00 +0100 4920885 http://www.medworm.com/index.php?rid=4920884&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1068%3Frss%3D1 Debranching enzymes, which hydrolyze α-1 and 6-glucosidic linkages in α-polyglucans, play a dual role in the synthesis and degradation of starch in plants. A transposon-inserted rice mutant of isoamylase3 (isa3) contained an increased amount of starch in the leaf blade at the end of the night, indicating that ISA3 plays a role in the degradation of transitory starch during the night. An epitope-tagged ISA3 expressed in Escherichia coli exhibited hydrolytic activity on β-limit dextrin and amylopectin. We investigated whether ISA3 plays a role in amyloplast development and starch metabolism in the developing endosperm. ISA3–green fluorescent protein (GFP) fusion protein expressed under the control of the rice ISA3 promoter was targeted to the amyloplast stroma in the e... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920884 Wed, 08 Jun 2011 23:00:00 +0100 4920884 http://www.medworm.com/index.php?rid=4920883&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1055%3Frss%3D1 Wild species often show more tolerance to environmental stress factors than their cultivated counterparts. An early responsive-to-dehydration gene was cloned from a drought- and salt-tolerant wild tomato Solanum pennellii (SpERD15). SpERD15 transcript accumulated differentially in different organs, and was remarkably induced by dehydration, salinity, cold and treatment with plant growth regulators. The protein encoded by SpERD15 was predominantly localized in the nucleus. Interestingly, we found that the majority of the transgenic tobacco plants were co-suppressed along with the overexpressing line. Overexpressing plants manifested stress tolerance accompanied by the accumulation of more soluble sugars and proline, and limited lipid peroxidation compared with co-suppression lines, which we... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920883 Wed, 08 Jun 2011 23:00:00 +0100 4920883 http://www.medworm.com/index.php?rid=4920882&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1042%3Frss%3D1 Cold-induced inhibition of CO2 assimilation in maize (Zea mays L.) is associated with a persistent depression of the photochemical efficiency of PSII. However, very limited information is available on PSI photochemistry and PSI-dependent electron flow in cold-stressed maize. The extent of the absorbance change (A820) used for in vivo quantitative estimation of photooxidizable P700+ indicated a 32% lower steady-state oxidation level of the PSI reaction center P700 (P700+) in cold-stressed compared with control maize leaves. This was accompanied by a 2-fold faster re-reduction rate of P700+ in the dark, indicating a higher capacity for cyclic electron flow (CEF) around PSI in cold-stressed maize leaves. Furthermore, the increased PSI-dependent CEF(s) was associated with a much higher stromal... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920882 Wed, 08 Jun 2011 23:00:00 +0100 4920882 http://www.medworm.com/index.php?rid=4920881&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1031%3Frss%3D1 Gentians are herbaceous perennials blooming in summer through autumn. Although they are popular ornamental flowers in Japan, the regulation of their timing of flowering has not been studied. We identified and characterized gentian orthologs of the Arabidopsis FT/TFL1 gene family to elucidate the mechanisms of flowering initiation. We isolated three gentian orthologs of FT and TFL1, denoted GtFT1, GtFT2 and GtTFL1. Since up-regulation of GtFT1 and GtFT2 as well as down-regulation of GtTFL1 promoted floral initiation in gentian plantlets, these genes affected floral initiation in a similar way to Arabidopsis FT and TFL1. The expression levels of GtFT1 and GtFT2 in leaves of late-flowering gentian increased prior to floral initiation, whereas GtTFL1 was highly expressed in shoot apical merist... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920881 Wed, 08 Jun 2011 23:00:00 +0100 4920881 http://www.medworm.com/index.php?rid=4920880&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1017%3Frss%3D1 Chloroplast development requires the coordinated action of various proteins, many of which remain to be identified. Here, we report two novel genes, Mesophyll-cell RNAi Library line 7 (MRL7) and MRL7-Like (MRL7-L), that are involved in this process. An Arabidopsis knock-down transgenic plant (MRL7-RNAi) with delayed-greening phenotype was isolated from an RNA interference (RNAi) transformant library. Cotyledons and young leaves of MRL7-RNAi were pale in seedlings and gradually greened as the plant matured, while a knock-out in the MRL7 gene was seedling lethal. The MRL7 protein was shown to co-localize with a marker protein for nucleoids in chloroplasts, indicative of a role for the protein in chloroplast nucleic acid metabolism. Accordingly, chloroplast development was arrested upon loss ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920880 Wed, 08 Jun 2011 23:00:00 +0100 4920880 http://www.medworm.com/index.php?rid=4920879&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F1003%3Frss%3D1 The rice prolamins consist of cysteine-rich 10 kDa (CysR10), 14 kDa (CysR14) and 16 kDa (CysR16) molecular species and a cysteine-poor 13 kDa (CysP13) polypeptide. These storage proteins form protein bodies (PBs) composed of single spherical intracisternal inclusions assembled within the lumen of the rough endoplasmic reticulum. Immunofluorescence and immunoelectron microscopy demonstrated that CysR10 and CysP13 were asymmetrically distributed within the PBs, with the former concentrated at the electron-dense center core region and the latter distributed mainly to the electron-lucent peripheral region. These results together with temporal expression data showed that the formation of prolamin-containing PB-I in the wild-type endosperm was initiated by the accumulation of CysR10 to form the ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920879 Wed, 08 Jun 2011 23:00:00 +0100 4920879 http://www.medworm.com/index.php?rid=4920878&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F994%3Frss%3D1 In this study, the metal binding properties of two related soybean LEA4 proteins, GmPM1 and GmPM9, were tested using immobilized metal ion affinity chromatography (IMAC). The metal ions Fe3+, Ni2+, Cu2+ and Zn2+ were observed to bind these two proteins, while Ca2+, Mg2+ or Mn2+ did not. Results from isothermal titration calorimetry (ITC) indicated that the binding affinity of GmPM1 for Fe3+ was stronger than that of GmPM9. Hydroxyl radicals generated by the Fe3+/H2O2 system were scavenged by both GmPM1 and GmPM9 in the absence or the presence of high ionic conditions (100 mM NaCl), although the scavenging activity of GmPM1 was significantly greater than that of GmPM9. These results suggest that GmPM1 and GmPM9 are metal-binding proteins which may function in reducing oxidative damage induc... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920878 Wed, 08 Jun 2011 23:00:00 +0100 4920878 http://www.medworm.com/index.php?rid=4920877&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F983%3Frss%3D1 Ricinoleic acid (12-hydroxy-octadeca-9-enoic acid) is a major unusual fatty acid in castor oil. This hydroxy fatty acid is useful in industrial materials. This unusual fatty acid accumulates in triacylglycerol (TAG) in the seeds of the castor bean (Ricinus communis L.), even though it is synthesized in phospholipids, which indicates that the castor plant has an editing enzyme, which functions as a phospholipid:diacylglycerol acyltransferase (PDAT) that is specific to ricinoleic acid. Transgenic plants containing fatty acid 12-hydroxylase encoded by the castor bean FAH12 gene produce a limited amount of hydroxy fatty acid, a maximum of around 17% of TAGs present in Arabidopsis seeds, and this unusual fatty acid remains in phospholipids of cell membranes in seeds. Identification of ricinolea... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920877 Wed, 08 Jun 2011 23:00:00 +0100 4920877 http://www.medworm.com/index.php?rid=4920876&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F967%3Frss%3D1 Thiamine is a key primary metabolite which is necessary for the viability of all organisms. It is a dietary requirement for mammals because only prokaryotes, fungi and plants are thiamine prototrophs. In contrast to the well documented biosynthetic mechanism in bacteria, much remains to be deciphered in plants. In this work, a tomato thiamine-auxotrophic (thiamineless, tl) mutant was characterized. The tl mutant occurs due to inactivation of LeTHIC transcription as a result of insertion of a large unknown DNA fragment in its 5'-untranslated region. Expression of wild-type LeTHIC in tl plants was able to complement the mutant to wild type. LeTHIC possessed the same function as E.cTHIC [an Escherichia coli 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate (HMP-P) synthase involved in synt... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920876 Wed, 08 Jun 2011 23:00:00 +0100 4920876 http://www.medworm.com/index.php?rid=4920875&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F6%2F957%3Frss%3D1 A thermophilic cyanobacterium, Thermosynechococcus vulcanus RKN, exhibits cell aggregation under low temperature illuminated conditions as a means of physiological acclimation to avoid excess light stress. The cell aggregation was dispersed with cellulase treatment. We developed a method to quantify small amounts of cellulose by partial cellulose purification followed by quantitation of liberated glucose by cellulase. Under low temperature illuminated light conditions, cellulose accumulation was induced approximately 2-fold, to 10 µg (4 x 109 cells)–1, and slightly preceded aggregation. Based on sequence similarity, three candidate genes for cellulose synthase (Tvtll0007, Tvtlr1795 and Tvtlr1930-33) were cloned from T. vulcanus. Gene disruption analysis showed that only Tvtll00... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4920875 Wed, 08 Jun 2011 23:00:00 +0100 4920875 http://www.medworm.com/index.php?rid=4820528&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F946%3Frss%3D1 In this study, results from V-ATPase complex disassembly with a chaotropic reagent, immunodetection and in vivo fluorescence resonance energy transfer (FRET) analyses point to a regulatory mechanism in plants, which depends on energization and involves the stability of the peripheral stalks as well. Lowering of cellular ATP by feeding 2-deoxyglucose resulted in structural alterations within the V-ATPase, as monitored by changes in FRET efficiency between subunits VHA-E and VHA-C. Potassium iodide-mediated disassembly revealed a reduced stability of V-ATPase after 2-deoxyglucose treatment of the cells, but neither the complete V1-sector nor VHA-C was released from the membrane in response to 2-deoxyglucose treatment, precluding a reversible dissociation mechanism like in yeast. These data s... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820528 Wed, 11 May 2011 23:00:00 +0100 4820528 http://www.medworm.com/index.php?rid=4820527&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F933%3Frss%3D1 Heat shock transcription factor A2 (HsfA2) acts as a key component of the Hsf signaling network involved in cellular responses to various types of environmental stress. However, the mechanism governing the regulation of HsfA2 expression is still largely unknown. We demonstrated here that a heat shock element (HSE) cluster in the 5'-flanking region of the HsfA2 gene is involved in high light (HL)-inducible HsfA2 expression. Accordingly, to identify the Hsf regulating the expression of HsfA2, we analyzed the effect of loss-of-function mutations of class A Hsfs on the expression of HsfA2 in response to HL stress. Overexpression of an HsfA1d or HsfA1e chimeric repressor and double knockout of HsfA1d and HsfA1e Arabidopsis mutants (KO-HsfA1d/A1e) significantly suppressed the induction of HsfA2 ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820527 Wed, 11 May 2011 23:00:00 +0100 4820527 http://www.medworm.com/index.php?rid=4820526&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F922%3Frss%3D1 In this report, we characterized the molecular events that occur during cryptogein-induced cell cycle arrest at G2 phase in synchronously cultured tobacco Bright Yellow-2 (BY-2) cells. Concomitant with the proteinaceous elicitor-induced G2 arrest, we observed inhibition of the histone H1 kinase activity of cyclin-dependent kinases (CDKs), which correlated with a decrease in mRNA and protein levels of CDKB1. In contrast, the amount of CDKA was almost unaffected by cryptogein even at M phase. Cryptogein rapidly inhibited the expression not only of positive, e.g. A- and B-type cyclins and NtCAK, but also of negative cell cycle regulators such as WEE1, suggesting that cryptogein affects multiple targets to inactivate CDKA to induce G2 arrest by mechanisms distinct from known checkpoint regulat... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820526 Wed, 11 May 2011 23:00:00 +0100 4820526 http://www.medworm.com/index.php?rid=4820525&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F909%3Frss%3D1 Inhibition of lycopene cyclization decreased the salt tolerance of the euhalophyte Salicornia europaea L. We isolated a β-lycopene cyclase gene SeLCY from S. europaea and transformed it into Arabidopsis with stable expression. Transgenic Arabidopsis on post-germination exhibited enhanced tolerance to oxidative and salt stress. After 8 and 21 d recovery from 200 mM NaCl treatment, transgenic lines had a higher survival ratio than wild-type (WT) plants. Three-week-old transgenic plants treated with 200 mM NaCl showed better growth than the WT with higher photosystem activity and less H2O2 accumulation. Determination of endogenous pigments of Arabidopsis treated with 200 mM NaCl for 0, 2 or 4 d demonstrated that the transgenic plants retained higher contents of carotenoids than the WT. F... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820525 Wed, 11 May 2011 23:00:00 +0100 4820525 http://www.medworm.com/index.php?rid=4820524&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F894%3Frss%3D1 GABA (-aminobutyric acid), a non-protein amino acid, is a signaling factor in many organisms. In plants, GABA is known to accumulate under a variety of stresses. However, the consequence of GABA accumulation, especially in vegetative tissues, remains poorly understood. Moreover, gene expression changes as a consequence of GABA accumulation in plants are largely unknown. The pop2 mutant, which is defective in GABA catabolism and accumulates GABA, is a good model to examine the effects of GABA accumulation on plant development. Here, we show that the pop2 mutants have pollen tube elongation defects in the transmitting tract of pistils. Additionally, we observed growth inhibition of primary root and dark-grown hypocotyl, at least in part due to cell elongation defects, upon exposure to exogen... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820524 Wed, 11 May 2011 23:00:00 +0100 4820524 http://www.medworm.com/index.php?rid=4820523&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F885%3Frss%3D1 Ulva sp. (Chlorophyta) is a representative species of the intertidal macro-algae responsible for the green tides that occurred along the shores of Qingdao in 2008 and had detrimental effects on the preparation for the 2008 Beijing Olympic Games sailing competition. In view of its significance, we have investigated the photosynthetic performance of the photosystems and the changes in photosynthetic electron transport that occur during desiccation and rehydration of Ulva sp. The PSII activity in Ulva sp. declined gradually during the course of desiccation, which was reflected by the decreased maximum quantum yield and effective quantum yield, whereas the PSI activity fluctuated significantly. In contrast, the electron transport rates of PSII approached zero at severe levels of desiccation, b... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820523 Wed, 11 May 2011 23:00:00 +0100 4820523 http://www.medworm.com/index.php?rid=4820522&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F874%3Frss%3D1 Caleosins or related sequences have been found in a wide range of higher plants. In Arabidopsis, seed-specific caleosins are viewed as oil-body (OB)-associated proteins that possess Ca2+-dependent peroxygenase activity and are involved in processes of lipid degradation. Recent experimental evidence suggests that one of the Arabidopsis non-seed caleosins, AtCLO3, is involved in controlling stomatal aperture during the drought response; the roles of the other caleosin-like proteins in Arabidopsis remain largely uncharacterized. We have demonstrated that a novel stress-responsive and OB-associated Ca2+-binding caleosin-like protein, AtCLO4, is expressed in non-seed tissues of Arabidopsis, including guard cells, and down-regulated following exposure to exogenous ABA and salt stress. At the see... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820522 Wed, 11 May 2011 23:00:00 +0100 4820522 http://www.medworm.com/index.php?rid=4820521&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F866%3Frss%3D1 The effects of the positive charges of amines such as spermine (SPM), putrescine (PUT) and methylamine (MET) on the protection of PSII against excessive illumination were investigated in isolated thylakoid membranes. Under photoinhibition conditions, water oxidation, the kinetics of the Chl fluorescence rise and charge recombination in PSII were affected. A low concentration of SPM (1 mM) added before photoinhibition produced a significant improvement of Fv/F0, the oxygen yield and the amplitude of the B-band of thermoluminescence compared with the other amines. Amongst the amines studied, only SPM could protect the photosynthetic apparatus under photoinhibition conditions. This protection was probably provided by the polycationic nature of SPM (four positive charges at physiological pH), ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820521 Wed, 11 May 2011 23:00:00 +0100 4820521 http://www.medworm.com/index.php?rid=4820520&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F851%3Frss%3D1 The pathway of carotenoids starts with the synthesis of phytoene and proceeds along a single path up to lycopene which can be transformed to β-carotene by the action of lycopene β-cyclase or to α-carotene through the sequential action of lycopene -cyclase and lycopene β-cyclase. All xanthophylls are produced from these two cyclic precursors following two hydroxylation steps. β,β-Xanthophyll biosynthesis requires hydroxylases belonging to the so-called ‘non-heme di-iron’ group while the biosynthesis of lutein involves enzymes belonging to the vast group of P450 monooxygenases with different enzymatic specificity due to the distinct rings of α-carotene. Here we report on the isolation and functional characterization of tomato CYP97A29 and CYP9... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820520 Wed, 11 May 2011 23:00:00 +0100 4820520 http://www.medworm.com/index.php?rid=4820519&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F837%3Frss%3D1 Higher plants contain biologically active proteins that are recognized by antibodies against human atrial natriuretic peptide (ANP). We identified and isolated two Arabidopsis thaliana immunoreactive plant natriuretic peptide (PNP)-encoding genes, AtPNP-A and AtPNP-B, which are distantly related members of the expansin superfamily and have a role in the regulation of homeostasis in abiotic and biotic stresses, and have shown that AtPNP-A modulates the effects of ABA on stomata. Arabidopsis PNP (PNP-A) is mainly expressed in leaf mesophyll cells, and in protoplast assays we demonstrate that it is secreted using AtPNP-A:green fluorescent protein (GFP) reporter constructs and flow cytometry. Transient reporter assays provide evidence that AtPNP-A expression is enhanced by heat, osmotica and s... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820519 Wed, 11 May 2011 23:00:00 +0100 4820519 http://www.medworm.com/index.php?rid=4820518&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F824%3Frss%3D1 Nitrate reductase (NR) is the enzyme that catalyzes the first step of nitrate assimilation. It is well known that the expression of NR genes is rapidly induced in various plants by nitrate. Previously, the activity of a tobacco NR gene promoter was reported to be high in tobacco plants grown on medium containing ammonium as the sole nitrogen source, but low in tobacco plants grown on nitrate-containing medium. This cast some doubt on the role of the NR gene promoter in the nitrate-inducible expression of this gene. Furthermore, in previous studies, transformation with genomic fragments containing NR loci restored the reduced NR activity in NR mutants to a limited extent, suggesting a complex regulation of NR gene expression. Here, we show that although the 1.9 kb promoter of an NR gene in ... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820518 Wed, 11 May 2011 23:00:00 +0100 4820518 http://www.medworm.com/index.php?rid=4820517&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F815%3Frss%3D1 The redox potential of the primary electron donor P700, Em(P700/P700+), of Photosystem I (PSI) has been determined for 10 oxygenic photosynthesis organisms, ranging from cyanobacteria, red algae, green algae to higher plants, by spectroelectrochemistry with an optically transparent thin-layer electrode (OTTLE) cell to elucidate the scattering by as much as 150 mV in reported values of Em(P700/P700+). The Em(P700/P700+) values determined within error ranges of ±1–4 mV exhibited a significant species dependence, with a span >70 mV, from +398 to +470 mV vs. the standard hydrogen electrode (SHE). The Em(P700/P700+) value appears to change systematically in going from cyanobacteria and primitive eukaryotic red algae, then to green algae and higher plants. From an evolutionary po... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820517 Wed, 11 May 2011 23:00:00 +0100 4820517 http://www.medworm.com/index.php?rid=4820516&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F804%3Frss%3D1 Shoot apical meristems (SAMs), which maintain stem cells at the tips of stems, and axillary meristems (AMs), which arise at leaf axils for branch formation, play significant roles in the establishment of plant architecture. Previously, we showed that, in Arabidopsis thaliana, activation of NB-LRR (nucleotide-binding site-leucine-rich repeat)-type UNI proteins affects plant morphology through modulation of the regulation of meristems. However, information about genes involved in the processes was still lacking. Here, we report that ERECTA (ER) receptor kinase family members cooperatively mediate the morphological alterations that are stimulated by activation of UNI proteins. uni-1D is a gain-of-function mutation in the UNI gene and uni-1D mutants exhibit early termination of inflorescence s... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820516 Wed, 11 May 2011 23:00:00 +0100 4820516 http://www.medworm.com/index.php?rid=4820515&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F785%3Frss%3D1 Accumulated transcriptome data can be used to investigate regulatory networks of genes involved in various biological systems. Co-expression analysis data sets generated from comprehensively collected transcriptome data sets now represent efficient resources that are capable of facilitating the discovery of genes with closely correlated expression patterns. In order to construct a co-expression network for barley, we analyzed 45 publicly available experimental series, which are composed of 1,347 sets of GeneChip data for barley. On the basis of a gene-to-gene weighted correlation coefficient, we constructed a global barley co-expression network and classified it into clusters of subnetwork modules. The resulting clusters are candidates for functional regulatory modules in the barley transc... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820515 Wed, 11 May 2011 23:00:00 +0100 4820515 http://www.medworm.com/index.php?rid=4820514&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F775%3Frss%3D1 In many temperate plant species, prolonged cold treatment, known as vernalization, is one of the most critical steps in the transition from the vegetative to the reproductive stage. In contrast to recent advances in understanding the molecular basis of vernalization in Arabidopsis non-vernalization mutants or the spring growth habits of cereal crops such as wheat and barley, natural variations in winter growth habits and their geographic distribution are poorly understood. We analyzed varietal variation and the geographic distribution of the degree of vernalization requirements in germplasms of domesticated barley and wild barley collections. We found a biased geographic distribution of vernalization requirements in domesticated barley: Western regions were strongly associated with a highe... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820514 Wed, 11 May 2011 23:00:00 +0100 4820514 http://www.medworm.com/index.php?rid=4820513&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F765%3Frss%3D1 Yellow stripe-like (YSL) family transporters, belonging to a novel subfamily of oligopeptide transporter (OPT), has been proposed to be involved in metal uptake and long-distance transport, but only a few of them have been functionally characterized so far. In the present study, we isolated an uncharacterized member of the YSL family, HvYSL5, in barley based on expressed sequence tag (EST) information. HvYSL5 shared 50% identity with HvYS1, a transporter for the ferric–mugineic acid complex, at the amino acid level. Promoter analysis showed that the HvYSL5 upstream sequence contains both iron deficiency response element 1 and 2 (IDE1 and 2). HvYSL5 was expressed in the roots and the expression was greatly induced by Fe deficiency, but not by deficiency of other metals including Zn, C... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820513 Wed, 11 May 2011 23:00:00 +0100 4820513 http://www.medworm.com/index.php?rid=4820512&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F750%3Frss%3D1 The evolution of the polyploid Triticum wheats is distinctive in that domestication, natural hybridization and allopolyploid speciation have all had significant impacts on their diversification. In this review, I outline the phylogenetic relationships of cultivated wheats and their wild relatives and provide an overview of the recent progress and remaining issues in understanding the genetic and ecological factors that favored their evolution. An attempt is made to view the evolution of the polyploid Triticum wheats as a continuous process of diversification that was initiated by domestication of tetraploid emmer wheat and driven by various natural events ranging from interploidy introgression via hybridization to allopolyploid speciation of hexaploid common wheat, instead of viewing it as... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820512 Wed, 11 May 2011 23:00:00 +0100 4820512 http://www.medworm.com/index.php?rid=4820511&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F738%3Frss%3D1 The process of crop domestication began 10,000 years ago in the transition of early humans from hunter/gatherers to pastoralists/farmers. Recent research has revealed the identity of some of the main genes responsible for domestication. Two of the major domestication events in barley were (i) the failure of the spike to disarticulate and (ii) the six-rowed spike. The former mutation increased grain yield by preventing grain loss after maturity, while the latter resulted in an up to 3-fold increase in yield potential. Here we provide an overview of the disarticulation systems and inflorescence characteristics, along with the genes underlying these traits, occurring in the Triticeae tribe. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820511 Wed, 11 May 2011 23:00:00 +0100 4820511 http://www.medworm.com/index.php?rid=4820510&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F728%3Frss%3D1 In this study, a diversity analysis using 1,301 SNPs on a set of 37 barley accessions was conducted. This analysis showed a high polymorphism rate between the malting barley cultivar ‘Haruna Nijo’ and the food barley cultivar ‘Akashinriki’. Haruna Nijo and Akashinriki are donors of the barley expressed sequence tag (EST) collections. A doubled haploid (DH) population derived from the cross between Haruna Nijo and Akashinriki was genotyped with 1,448 SNPs. Of these 1,448 SNPs, 734 were polymorphic and distributed on barley linkage groups (chromosomes) as follows: 1H (86), 2H (125), 3H (120), 4H (100), 5H (127), 6H (88) and 7H (88). By using cMAP, we integrated the SNP markers across high-density maps. The SNPs were also used to genotype 98 BC3F4 recombinant chromosom... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820510 Wed, 11 May 2011 23:00:00 +0100 4820510 http://www.medworm.com/index.php?rid=4820509&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F724%3Frss%3D1 (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820509 Wed, 11 May 2011 23:00:00 +0100 4820509 http://www.medworm.com/index.php?rid=4820508&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F5%2F723%3Frss%3D1 (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4820508 Wed, 11 May 2011 23:00:00 +0100 4820508 http://www.medworm.com/index.php?rid=4693090&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F4%2F716%3Frss%3D1 We describe the pipeline of this methodology and discuss its characteristics. (Source: Plant and Cell Physiology) Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4693090 Thu, 07 Apr 2011 23:00:00 +0100 4693090 http://www.medworm.com/index.php?rid=4693089&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F4%2F699%3Frss%3D1 Strigolactones are important signaling compounds in the plant kingdom. Here we focus on their germination stimulatory effect on seeds of the parasitic weeds Striga and Orobanche spp. and more particularly on the design and synthesis of new active strigolactone analogs derived from simple cyclic ketones. New analogs derived from 1-indanone, 1-tetralone, cyclopentanone, cyclohexanone and a series of substituted cyclohexanones (including carvone and pulegone) are prepared by formylation of the ketones with ethyl formate followed by coupling with a halo butenolide. Both enantiomers of the analog derived from 1-tetralone have been prepared by employing a homochiral synthon for the coupling reaction. For three other strigolactone analogs the antipodes have been obtained by chromatography on a ch... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4693089 Thu, 07 Apr 2011 23:00:00 +0100 4693089 http://www.medworm.com/index.php?rid=4693088&cid=s_32024_171_f&fid=32024&url=http%3A%2F%2Fpcp.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F52%2F4%2F689%3Frss%3D1 The production of both ABA and H2O2 is induced by drought and can act as signals under stress conditions. We investigated the relationships between ABA, H2O2 and catalase (CAT) in rice leaves when rice seedlings were treated with polyethylene glycol as water stress treatment. As a key gene in ABA biosynthesis, OsNCED3 was significantly induced in rice by water stress treatment and such induction preceded the rapid increase in ABA. Water stress inhibited the expression of CATA and CATC but substantially enhanced the expression of CATB. Exogenously applied ABA promoted the expression of CATB also and inhibited the expression of CATC in a concentration-dependent manner. When ABA production was inhibited by using ABA biosynthesis inhibitors nordihydroguaiaretic acid and tungstate, expression o... Plant and Cell Physiology journals http://www.medworm.com/rss/comments.php?id=4693088 Thu, 07 Apr 2011 23:00:00 +0100 4693088