| sexual and apomictic seed formation in hieracium requires the plant polycomb-group gene fertilization independent endosperm. | a polycomb-group (pcg) complex, fertilization independent seed (fis), represses endosperm development in arabidopsis thaliana until fertilization occurs. the hieracium genus contains apomictic species that form viable seeds asexually. to investigate fis function during apomictic seed formation, fertilization independent endosperm (fie), encoding a wd-repeat member of the fis complex, was isolated and downregulated in sexual and apomictic hieracium species. general downregulation led to defects i ... | 2008 | 18812497 |
| proteolysis-independent downregulation of della repression in arabidopsis by the gibberellin receptor gibberellin insensitive dwarf1. | this article presents evidence that della repression of gibberellin (ga) signaling is relieved both by proteolysis-dependent and -independent pathways in arabidopsis thaliana. della proteins are negative regulators of ga responses, including seed germination, stem elongation, and fertility. ga stimulates ga responses by causing della repressor degradation via the ubiquitin-proteasome pathway. della degradation requires ga biosynthesis, three functionally redundant ga receptors gibberellin insens ... | 2008 | 18827182 |
| release of the repressive activity of rice della protein slr1 by gibberellin does not require slr1 degradation in the gid2 mutant. | the rice (oryza sativa) della protein slr1 acts as a repressor of gibberellin (ga) signaling. ga perception by gid1 causes slr1 protein degradation involving the f-box protein gid2; this triggers ga-associated responses such as shoot elongation and seed germination. in ga-insensitive and ga biosynthesis mutants, slender rice1 (slr1) accumulates to high levels, and the severity of dwarfism is usually correlated with the level of slr1 accumulation. an exception is the ga-insensitive f-box mutant g ... | 2008 | 18827181 |
| overexpression of the arabidopsis 10-kilodalton acyl-coenzyme a-binding protein acbp6 enhances freezing tolerance. | small 10-kd acyl-coenzyme a-binding proteins (acbps) are highly conserved proteins that are prevalent in eukaryotes. in arabidopsis (arabidopsis thaliana), other than the 10-kd acbp homolog (designated arabidopsis acbp6), there are five larger forms of acbps ranging from 37.5 to 73.1 kd. in this study, the cytosolic subcellular localization of arabidopsis acbp6 was confirmed by analyses of transgenic arabidopsis expressing autofluorescence-tagged acbp6 and western-blot analysis of subcellular fr ... | 2008 | 18621979 |
| a novel rna-binding protein associated with cell plate formation. | building a cell plate during cytokinesis in plant cells requires the participation of a number of proteins in a multistep process. we previously identified phragmoplastin as a cell plate-specific protein involved in creating a tubulovesicular network at the cell plate. we report here the identification and characterization of a phragmoplastin-interacting protein, phip1, in arabidopsis (arabidopsis thaliana). it contains multiple functional motifs, including a lysine-rich domain, two rna recognit ... | 2008 | 18621982 |
| mobilization of rubisco and stroma-localized fluorescent proteins of chloroplasts to the vacuole by an atg gene-dependent autophagic process. | during senescence and at times of stress, plants can mobilize needed nitrogen from chloroplasts in leaves to other organs. much of the total leaf nitrogen is allocated to the most abundant plant protein, rubisco. while bulk degradation of the cytosol and organelles in plants occurs by autophagy, the role of autophagy in the degradation of chloroplast proteins is still unclear. we have visualized the fate of rubisco, stroma-targeted green fluorescent protein (gfp) and dsred, and gfp-labeled rubis ... | 2008 | 18614709 |
| the coenzyme a biosynthetic enzyme phosphopantetheine adenylyltransferase plays a crucial role in plant growth, salt/osmotic stress resistance, and seed lipid storage. | coenzyme a (coa) is an essential cofactor in the metabolism of both prokaryotic and eukaryotic organisms and a universal five-step pathway is utilized to synthesize coa from pantothenate. null mutations in two of the five steps of this pathway led to embryo lethality and therefore viable reduction-of-function mutations are required to further study its role in plant biology. in this article, we have characterized a viable arabidopsis (arabidopsis thaliana) t-dna mutant affected in the penultimat ... | 2008 | 18621975 |
| combination of novel green fluorescent protein mutant tsapphire and dsred variant morange to set up a versatile in planta fret-flim assay. | förster resonance energy transfer (fret) measurements based on fluorescence lifetime imaging microscopy (flim) are increasingly being used to assess molecular conformations and associations in living systems. reduction in the excited-state lifetime of the donor fluorophore in the presence of an appropriately positioned acceptor is taken as strong evidence of fret. traditionally, cyan fluorescent protein has been widely used as a donor fluorophore in fret experiments. however, given its photolabi ... | 2008 | 18621983 |
| functional characterization of the arabidopsis atsuc2 sucrose/h+ symporter by tissue-specific complementation reveals an essential role in phloem loading but not in long-distance transport. | atsuc2 (at1g22710) encodes a phloem-localized sucrose (suc)/h(+) symporter necessary for efficient suc transport from source tissues to sink tissues in arabidopsis (arabidopsis thaliana). atsuc2 is highly expressed in the collection phloem of mature leaves, and its function in phloem loading is well established. atsuc2, however, is also expressed strongly in the transport phloem, where its role is more ambiguous, and it has been implicated in mediating both efflux and retrieval to and from flank ... | 2008 | 18650401 |
| seven in absentia proteins affect plant growth and nodulation in medicago truncatula. | protein ubiquitination is a posttranslational regulatory process essential for plant growth and interaction with the environment. e3 ligases, to which the seven in absentia (sina) proteins belong, determine the specificity by selecting the target proteins for ubiquitination. sina proteins are found in animals as well as in plants, and a small gene family with highly related members has been identified in the genome of rice (oryza sativa), arabidopsis (arabidopsis thaliana), medicago truncatula, ... | 2008 | 18599652 |
| arabidopsis somatic embryogenesis receptor kinase proteins serve brassinosteroid-dependent and -independent signaling pathways. | the arabidopsis (arabidopsis thaliana) somatic embryogenesis receptor kinase (serk) genes belong to a small family of five plant receptor kinases that are involved in at least five different signaling pathways. one member of this family, brassinosteroid insensitive1 (bri1)-associated kinase1 (bak1), also known as serk3, is the coreceptor of the brassinolide (br)-perceiving receptor bri1, a function that is br dependent and partially redundant with serk1. bak1 (serk3) alone controls plant innate ... | 2008 | 18667726 |
| noise reduction by diffusional dissipation in a minimal quorum sensing motif. | cellular interactions are subject to random fluctuations (noise) in quantities of interacting molecules. noise presents a major challenge for the robust function of natural and engineered cellular networks. past studies have analyzed how noise is regulated at the intracellular level. cell-cell communication, however, may provide a complementary strategy to achieve robust gene expression by enabling the coupling of a cell with its environment and other cells. to gain insight into this issue, we h ... | 2008 | 18769706 |
| the phytochrome red/far-red photoreceptor superfamily. | proteins of the phytochrome superfamily of red/far-red light receptors have a variety of biological roles in plants, algae, bacteria and fungi and demonstrate a diversity of spectral sensitivities and output signaling mechanisms. over the past few years the first three-dimensional structures of phytochrome light-sensing domains from bacteria have been determined. | 2008 | 18771590 |
| cooperative activity of dna methyltransferases for maintenance of symmetrical and non-symmetrical cytosine methylation in arabidopsis thaliana. | maintenance of cytosine methylation in plants is controlled by three dna methyltransferases. met1 maintains cg methylation, and drm1/2 and cmt3 act redundantly to enforce non-cg methylation. rps, a repetitive hypermethylated dna fragment from petunia hybrida, attracts dna methylation when transferred into petunia or other species. in arabidopsis thaliana, which does not contain any rps homologues, rps transgenes are efficiently methylated in all sequence contexts. to test which dna methylation p ... | 2008 | 18665914 |
| rid1, encoding a cys2/his2-type zinc finger transcription factor, acts as a master switch from vegetative to floral development in rice. | transition from the vegetative phase to reproductive phase is a crucial process in the life cycle of higher plants. although the molecular mechanisms of flowering regulation have been extensively characterized in a number of plant species, little is known regarding how the transition process initiates. here, we show that the rice indeterminate 1 (rid1) gene acts as the master switch for the transition from the vegetative to reproductive phase. rid1 encodes a cys-2/his-2-type zinc finger transcri ... | 2008 | 18725639 |
| sensing of 'danger signals' and pathogen-associated molecular patterns defines binary signaling pathways 'upstream' of toll. | in drosophila, molecular determinants from fungi and gram-positive bacteria are detected by circulating pattern-recognition receptors. published findings suggest that such pattern-recognition receptors activate as-yet-unidentified serine-protease cascades that culminate in the cleavage of spätzle, the endogenous toll receptor ligand, and trigger the immune response. we demonstrate here that the protease grass defines a common activation cascade for the detection of fungi and gram-positive bacter ... | 2008 | 18724373 |
| molecular identification of a major quantitative trait locus, qltg3-1, controlling low-temperature germinability in rice. | tolerance to abiotic stress is an important agronomic trait in crops and is controlled by many genes, which are called quantitative trait loci (qtls). identification of these qtls will contribute not only to the understanding of plant biology but also for plant breeding, to achieve stable crop production around the world. previously, we mapped three qtls controlling low-temperature tolerance at the germination stage (called low-temperature germinability). to understand the molecular basis of one ... | 2008 | 18719107 |
| role of polyphosphates in microbial adaptation to extreme environments. | | 2008 | 18708516 |
| three sra-domain methylcytosine-binding proteins cooperate to maintain global cpg methylation and epigenetic silencing in arabidopsis. | methylcytosine-binding proteins decipher the epigenetic information encoded by dna methylation and provide a link between dna methylation, modification of chromatin structure, and gene silencing. variant in methylation 1 (vim1) encodes an sra (set- and ring-associated) domain methylcytosine-binding protein in arabidopsis thaliana, and loss of vim1 function causes centromere dna hypomethylation and centromeric heterochromatin decondensation in interphase. in the arabidopsis genome, there are five ... | 2008 | 18704160 |
| effector genomics accelerates discovery and functional profiling of potato disease resistance and phytophthora infestans avirulence genes. | potato is the world's fourth largest food crop yet it continues to endure late blight, a devastating disease caused by the irish famine pathogen phytophthora infestans. breeding broad-spectrum disease resistance (r) genes into potato (solanum tuberosum) is the best strategy for genetically managing late blight but current approaches are slow and inefficient. we used a repertoire of effector genes predicted computationally from the p. infestans genome to accelerate the identification, functional ... | 2008 | 18682852 |
| subcellular localization of overexpressed maize ache gene in rice plant. | the ach-mediated system consisting of acetylcholine (ach), acetylcholine receptor (achr) and acetylcholinesterase (ache) is fundamental for nervous system function in animals and insects. although plants lack a nervous system, both ach and ach-hydrolyzing activity have been widely recognized in the plant kingdom. the function of the plant ach-mediated system is still unclear, despite more than 30 years of research. to understand ach-mediated systems in plants, we previously purified maize ache a ... | 2008 | 19704473 |
| towards a reporter system to identify regulators of cross-talk between salicylate and jasmonate signaling pathways in arabidopsis. | the plant signaling hormones salicylic acid (sa) and jasmonic acid (ja) are regulators of inducible defenses that are activated upon pathogen or insect attack. cross-talk between sa- and ja-dependent signaling pathways allows a plant to finely tune its response to the attacker encountered. in arabidopsis, pharmacological experiments revealed that sa exerts a strong antagonistic effect on ja-responsive genes, such as pdf1.2, indicating that the sa pathway can be prioritized over the ja pathway. s ... | 2008 | 19513248 |
| patterning of inflorescences and flowers by the f-box protein double top and the leafy homolog aberrant leaf and flower of petunia. | angiosperms display a wide variety of inflorescence architectures differing in the positions where flowers or branches arise. the expression of floral meristem identity (fmi) genes determines when and where flowers are formed. in arabidopsis thaliana, this is regulated via transcription of leafy (lfy), which encodes a transcription factor that promotes fmi. we found that this is regulated in petunia (petunia hybrida) via transcription of a distinct gene, double top (dot), a homolog of unusual fl ... | 2008 | 18713949 |
| the arabidopsis nfya5 transcription factor is regulated transcriptionally and posttranscriptionally to promote drought resistance. | nuclear factor y (nf-y) is a ubiquitous transcription factor composed of three distinct subunits (nf-ya, nf-yb, and nf-yc). we found that the arabidopsis thaliana nfya5 transcript is strongly induced by drought stress in an abscisic acid (aba)-dependent manner. promoter:beta-glucuronidase analyses showed that nfya5 was highly expressed in vascular tissues and guard cells and that part of the induction by drought was transcriptional. nfya5 contains a target site for mir169, which targets mrnas fo ... | 2008 | 18682547 |
| arabidopsis thaliana homeobox gene1 establishes the basal boundaries of shoot organs and controls stem growth. | apical meristems play a central role in plant development. self-renewing cells in the central region of the shoot meristem replenish the cell population in the peripheral region, where organ primordia emerge in a predictable pattern, and in the underlying rib meristem, where new stem tissue is formed. while much is known about how organ primordia are initiated and their lateral boundaries established, development at the interface between the stem and the meristem or the lateral organs is poorly ... | 2008 | 18757555 |
| functional diversification of clavata3-related cle proteins in meristem maintenance in rice. | postembryonic development in plants depends on the activity of the shoot apical meristem (sam) and root apical meristem (ram). in arabidopsis thaliana, clavata signaling negatively regulates the size of the stem cell population in the sam by repressing wuschel. in other plants, however, studies of factors involved in stem cell maintenance are insufficient. here, we report that two proteins closely related to clavata3, floral organ number2 (fon2) and fon2-like cle protein1 (fcp1/os cle402), have ... | 2008 | 18676878 |
| comprehensive flavonol profiling and transcriptome coexpression analysis leading to decoding gene-metabolite correlations in arabidopsis. | to complete the metabolic map for an entire class of compounds, it is essential to identify gene-metabolite correlations of a metabolic pathway. we used liquid chromatography-mass spectrometry (lc-ms) to identify the flavonoids produced by arabidopsis thaliana wild-type and flavonoid biosynthetic mutant lines. the structures of 15 newly identified and eight known flavonols were deduced by lc-ms profiling of these mutants. candidate genes presumably involved in the flavonoid pathway were delimite ... | 2008 | 18757557 |
| the cold-inducible cbf1 factor-dependent signaling pathway modulates the accumulation of the growth-repressing della proteins via its effect on gibberellin metabolism. | plants have evolved robust mechanisms to respond and adapt to unfavorable environmental conditions, such as low temperature. the c-repeat/drought-responsive element binding factor cbf1/dreb1b gene encodes a transcriptional activator transiently induced by cold that controls the expression of a set of genes responding to low temperature (the cbf regulon). constitutive expression of cbf1 confers freezing tolerance but also slows growth. here, we propose that low temperature-induced cbf1 expression ... | 2008 | 18757556 |
| brassinosteroids regulate grain filling in rice. | genes controlling hormone levels have been used to increase grain yields in wheat (triticum aestivum) and rice (oryza sativa). we created transgenic rice plants expressing maize (zea mays), rice, or arabidopsis thaliana genes encoding sterol c-22 hydroxylases that control brassinosteroid (br) hormone levels using a promoter that is active in only the stems, leaves, and roots. the transgenic plants produced more tillers and more seed than wild-type plants. the seed were heavier as well, especiall ... | 2008 | 18708477 |
| imaging of the yellow cameleon 3.6 indicator reveals that elevations in cytosolic ca2+ follow oscillating increases in growth in root hairs of arabidopsis. | in tip-growing cells, the tip-high ca(2+) gradient is thought to regulate the activity of components of the growth machinery, including the cytoskeleton, ca(2+)-dependent regulatory proteins, and the secretory apparatus. in pollen tubes, both the ca(2+) gradient and cell elongation show oscillatory behavior, reinforcing the link between the two. we report that in growing root hairs of arabidopsis (arabidopsis thaliana), an oscillating tip-focused ca(2+) gradient can be resolved through imaging o ... | 2008 | 18583529 |
| comparison of the dynamics and functional redundancy of the arabidopsis dynamin-related isoforms drp1a and drp1c during plant development. | members of the arabidopsis (arabidopsis thaliana) dynamin-related protein1 (drp1) family are required for cytokinesis and cell expansion. two isoforms, drp1a and drp1c, are required for plasma membrane maintenance during stigmatic papillae expansion and pollen development, respectively. it is unknown whether the drp1s function interchangeably or if they have distinct roles during cell division and expansion. drp1c was previously shown to form dynamic foci in the cell cortex, which colocalize wit ... | 2008 | 18344418 |
| mutation of the rice narrow leaf1 gene, which encodes a novel protein, affects vein patterning and polar auxin transport. | the size and shape of the plant leaf is an important agronomic trait. to understand the molecular mechanism governing plant leaf shape, we characterized a classic rice (oryza sativa) dwarf mutant named narrow leaf1 (nal1), which exhibits a characteristic phenotype of narrow leaves. in accordance with reduced leaf blade width, leaves of nal1 contain a decreased number of longitudinal veins. anatomical investigations revealed that the culms of nal1 also show a defective vascular system, in which t ... | 2008 | 18562767 |
| retarded growth of embryo1, a new basic helix-loop-helix protein, expresses in endosperm to control embryo growth. | we have isolated two dominant mutants from screening approximately 50,000 riken activation-tagging lines that have short inflorescence internodes. the activation t-dnas were inserted near a putative basic helix-loop-helix (bhlh) gene and expression of this gene was increased in the mutant lines. overexpression of this bhlh gene produced the original mutant phenotype, indicating it was responsible for the mutants. specific expression was observed during seed development. the loss-of-function muta ... | 2008 | 18567831 |
| involvement of the mads-box gene zmm4 in floral induction and inflorescence development in maize. | the switch from vegetative to reproductive growth is marked by the termination of vegetative development and the adoption of floral identity by the shoot apical meristem (sam). this process is called the floral transition. to elucidate the molecular determinants involved in this process, we performed genome-wide rna expression profiling on maize (zea mays) shoot apices at vegetative and early reproductive stages using massively parallel signature sequencing technology. profiling revealed signifi ... | 2008 | 18539775 |
| the pra1 gene family in arabidopsis. | prenylated rab acceptor 1 (pra1) domain proteins are small transmembrane proteins that regulate vesicle trafficking as receptors of rab gtpases and the vacuolar soluble n-ethylmaleimide-sensitive factor attachment receptor protein vamp2. however, little is known about pra1 family members in plants. sequence analysis revealed that higher plants, compared with animals and primitive plants, possess an expanded family of pra1 domain-containing proteins. the arabidopsis (arabidopsis thaliana) pra1 (a ... | 2008 | 18583532 |
| comprehensive analysis of single-repeat r3 myb proteins in epidermal cell patterning and their transcriptional regulation in arabidopsis. | single-repeat r3 myb transcription factors are critical components of the lateral inhibition machinery that mediates epidermal cell patterning in plants. sequence analysis of the arabidopsis genome using the blast program reveals that there are a total of six genes, including triptychon (try), caprice (cpc), trichomeless1 (tcl1), and enhancer of try and cpc 1, 2, and 3 (etc1, etc2 and etc3) encoding single-repeat r3 myb transcription factors that are approximately 50% identical to one another at ... | 2008 | 18644155 |
| stress regulated members of the plant organic cation transporter family are localized to the vacuolar membrane. | in arabidopsis six genes group into the gene family of the organic cation transporters (octs). in animals the members of the oct-family are mostly characterized as polyspecific transporters involved in the homeostasis of solutes, the transport of monoamine neurotransmitters and the transport of choline and carnitine. in plants little is known about function, localisation and regulation of this gene family. only one protein has been characterized as a carnitine transporter at the plasma membrane ... | 2008 | 18710496 |
| involvement of rte1 in conformational changes promoting etr1 ethylene receptor signaling in arabidopsis. | ethylene is an important regulator of plant growth, development and responses to environmental stresses. arabidopsis perceives ethylene through five homologous receptors that negatively regulate ethylene responses. rte1, a novel gene conserved in plants, animals and some protists, was recently identified as a positive regulator of the etr1 ethylene receptor. here, we genetically analyze the dependence of etr1 on rte1 in order to obtain further insight into rte1 function. the function of rte1 was ... | 2008 | 18643990 |
| identification of a cis-regulatory element by transient analysis of co-ordinately regulated genes. | transcription factors (tfs) co-ordinately regulate target genes that are dispersed throughout the genome. this co-ordinate regulation is achieved, in part, through the interaction of transcription factors with conserved cis-regulatory motifs that are in close proximity to the target genes. while much is known about the families of transcription factors that regulate gene expression in plants, there are few well characterised cis-regulatory motifs.in arabidopsis, over-expression of the myb transc ... | 2008 | 18601751 |
| head-neck domain of arabidopsis myosin xi, mya2, fused with gfp produces f-actin patterns that coincide with fast organelle streaming in different plant cells. | the cytoskeletal mechanisms that underlie organelle transport in plants are intimately linked to acto-myosin function. this function is mediated by the attachment of myosin heads to f-actin and the binding of cargo to the tails. acto-myosin also powers vigorous cytoplasmic streaming in plant cells. class xi myosins exhibit strikingly fast velocities and may have extraordinary roles in cellular motility. studies of the structural basis of organelle transport have focused on the cargo-binding tail ... | 2008 | 18598361 |
| viral genome methylation as an epigenetic defense against geminiviruses. | geminiviruses encapsidate single-stranded dna genomes that replicate in plant cell nuclei through double-stranded dna intermediates that associate with cellular histone proteins to form minichromosomes. like most plant viruses, geminiviruses are targeted by rna silencing and encode suppressor proteins such as al2 and l2 to counter this defense. these related proteins can suppress silencing by multiple mechanisms, one of which involves interacting with and inhibiting adenosine kinase (adk), a cel ... | 2008 | 18596098 |
| badh2, encoding betaine aldehyde dehydrogenase, inhibits the biosynthesis of 2-acetyl-1-pyrroline, a major component in rice fragrance. | in rice (oryza sativa), the presence of a dominant badh2 allele encoding betaine aldehyde dehydrogenase (badh2) inhibits the synthesis of 2-acetyl-1-pyrroline (2ap), a potent flavor component in rice fragrance. by contrast, its two recessive alleles, badh2-e2 and badh2-e7, induce 2ap formation. badh2 was found to be transcribed in all tissues tested except for roots, and the transcript was detected at higher abundance in young, healthy leaves than in other tissues. multiple badh2 transcript leng ... | 2008 | 18599581 |
| the epip peptide of inflorescence deficient in abscission is sufficient to induce abscission in arabidopsis through the receptor-like kinases haesa and haesa-like2. | in arabidopsis thaliana, the final step of floral organ abscission is regulated by inflorescence deficient in abscission (ida): ida mutants fail to abscise floral organs, and plants overexpressing ida display earlier abscission. we show that five ida-like (idl) genes are expressed in different tissues, but plants overexpressing these genes have phenotypes similar to ida-overexpressing plants, suggesting functional redundancy. ida/idl proteins have n-terminal signal peptides and a c-terminal cons ... | 2008 | 18660431 |
| mutations in suppressor of variegation1, a factor required for normal chloroplast translation, suppress var2-mediated leaf variegation in arabidopsis. | the arabidopsis thaliana yellow variegated2 (var2) mutant is variegated due to lack of a chloroplast ftsh-like metalloprotease (ftsh2/var2). we have generated suppressors of var2 variegation to gain insight into factors and pathways that interact with var2 during chloroplast biogenesis. here, we describe two such suppressors. suppression of variegation in the first line, tag-fn, was caused by disruption of the nuclear gene (suppressor of variegation1 [svr1]) for a chloroplast-localized homolog o ... | 2008 | 18599582 |
| the potato-specific apyrase is apoplastically localized and has influence on gene expression, growth, and development. | apyrases hydrolyze nucleoside triphosphates and diphosphates and are found in all eukaryotes and a few prokaryotes. although their enzymatic properties have been well characterized, relatively little is known regarding their subcellular localization and physiological function in plants. in this study, we used reverse genetic and biochemical approaches to investigate the role of potato (solanum tuberosum)-specific apyrase. silencing of the apyrase gene family with rna interference constructs unde ... | 2008 | 18480378 |
| galactinol and raffinose constitute a novel function to protect plants from oxidative damage. | galactinol synthase (gols) is a key enzyme in the synthesis of raffinose family oligosaccharides that function as osmoprotectants in plant cells. in leaves of arabidopsis (arabidopsis thaliana) plants overexpressing heat shock transcription factor a2 (hsfa2), the transcription of gols1, -2, and -4 and raffinose synthase 2 (rs2) was highly induced; thus, levels of galactinol and raffinose increased compared with those in wild-type plants under control growth conditions. in leaves of the wild-type ... | 2008 | 18502973 |
| characterization and biological function of the isochorismate synthase2 gene of arabidopsis. | salicylic acid (sa) is an important mediator of plant defense response. in arabidopsis (arabidopsis thaliana), this compound was proposed to derive mainly from isochorismate, itself produced from chorismate through the activity of isochorismate synthase1 (ics1). null ics1 mutants still accumulate some sa, suggesting the existence of an enzymatic activity redundant with ics1 or of an alternative ics-independent sa biosynthetic route. here, we studied the role of ics2, a second ics gene of the ara ... | 2008 | 18451262 |
| the beta-glucosidases responsible for bioactivation of hydroxynitrile glucosides in lotus japonicus. | lotus japonicus accumulates the hydroxynitrile glucosides lotaustralin, linamarin, and rhodiocyanosides a and d. upon tissue disruption, the hydroxynitrile glucosides are bioactivated by hydrolysis by specific beta-glucosidases. a mixture of two hydroxynitrile glucoside-cleaving beta-glucosidases was isolated from l. japonicus leaves and identified by protein sequencing as ljbgd2 and ljbgd4. the isolated hydroxynitrile glucoside-cleaving beta-glucosidases preferentially hydrolyzed rhodiocyanosid ... | 2008 | 18467457 |
| rna-directed rna polymerase3 from nicotiana attenuata is required for competitive growth in natural environments. | sde1/sgs2/rdr6, a putative rna-directed rna polymerase, maintains plant defenses against viruses in arabidopsis (arabidopsis thaliana) and nicotiana benthamiana, but its function has not been examined in natural habitats or with respect to other ecological stresses. we evaluated the organismic-level function of this gene (nardr3) in an ecological model species, nicotiana attenuata, by transforming plants to stably silence rdr3 (irrdr3). minor morphological changes (elongated leaves and reduced l ... | 2008 | 18480375 |
| global identification of della target genes during arabidopsis flower development. | gibberellin (ga) plays important roles in regulating many aspects of plant development. ga derepresses its signaling pathway by promoting the degradation of della proteins, a family of nuclear growth repressors. although the floral organ identity is established in flowers of the ga-deficient mutant ga1-3, the growth of all floral organs is severely retarded. in particular, abortive anther development in ga1-3 results in male sterility. genetic analysis has revealed that various combinations of n ... | 2008 | 18502975 |
| the transcriptional repressor arr1-srdx suppresses pleiotropic cytokinin activities in arabidopsis. | the signal transduction of the phytohormone cytokinin is mediated by a multistep histidine-to-aspartate phosphorelay system. one component of this system are b-type response regulators, transcription factors mediating at least part of the response to cytokinin. in planta functional analysis of this family is hampered by the high level of functional redundancy of its 11 members. we generated a dominant repressor version of the arabidopsis (arabidopsis thaliana) response regulator arr1 (arr1-srdx) ... | 2008 | 18502977 |
| unraveling microbial interactions in food fermentations: from classical to genomics approaches. | | 2008 | 18567682 |
| auxin acts as a local morphogenetic trigger to specify lateral root founder cells. | plants exhibit an exceptional adaptability to different environmental conditions. to a large extent, this adaptability depends on their ability to initiate and form new organs throughout their entire postembryonic life. plant shoot and root systems unceasingly branch and form axillary shoots or lateral roots, respectively. the first event in the formation of a new organ is specification of founder cells. several plant hormones, prominent among them auxin, have been implicated in the acquisition ... | 2008 | 18559858 |
| regulation and role of arabidopsis cul4-ddb1a-ddb2 in maintaining genome integrity upon uv stress. | plants use the energy in sunlight for photosynthesis, but as a consequence are exposed to the toxic effect of uv radiation especially on dna. the uv-induced lesions on dna affect both transcription and replication and can also have mutagenic consequences. here we investigated the regulation and the function of the recently described cul4-ddb1-ddb2 e3 ligase in the maintenance of genome integrity upon uv-stress using the model plant arabidopsis. physiological, biochemical, and genetic evidences i ... | 2008 | 18551167 |
| the effects of enhanced methionine synthesis on amino acid and anthocyanin content of potato tubers. | potato is a staple food in the diet of the world's population and also being used as animal feed. compared to other crops, however, potato tubers are relatively poor in the essential amino acid, methionine. our aim was to increase the methionine content of tubers by co-expressing a gene involved in methionine synthesis with a gene encoding a methionine-rich storage protein in potato plants. | 2008 | 18549488 |
| a polyadenylation factor subunit implicated in regulating oxidative signaling in arabidopsis thaliana. | plants respond to many unfavorable environmental conditions via signaling mediated by altered levels of various reactive oxygen species (ros). to gain additional insight into oxidative signaling responses, arabidopsis mutants that exhibited tolerance to oxidative stress were isolated. we describe herein the isolation and characterization of one such mutant, oxt6. | 2008 | 18545667 |
| generating and testing molecular hypotheses in the dermatophytes. | | 2008 | 18539886 |
| the dna replication checkpoint aids survival of plants deficient in the novel replisome factor etg1. | complete and accurate chromosomal dna replication is essential for the maintenance of the genetic integrity of all organisms. errors in replication are buffered by the activation of dna stress checkpoints; however, in plants, the relative importance of a coordinated induction of dna repair and cell cycle-arresting genes in the survival of replication mutants is unknown. in a systematic screen for arabidopsis thaliana e2f target genes, the e2f target gene 1 (etg1) was identified as a novel evolut ... | 2008 | 18528439 |
| targeted degradation of the cyclin-dependent kinase inhibitor ick4/krp6 by ring-type e3 ligases is essential for mitotic cell cycle progression during arabidopsis gametogenesis. | following meiosis, plant gametophytes develop through two or three rounds of mitosis. although the ontogeny of gametophyte development has been defined in arabidopsis thaliana, the molecular mechanisms regulating mitotic cell cycle progression are not well understood. here, we report that ring-h2 group f 1a (rhf1a) and rhf2a, two ring-finger e3 ligases, play an important role in arabidopsis gametogenesis. the rhf1a rhf2a double mutants are defective in the formation of male and female gametophyt ... | 2008 | 18552199 |
| two distinct interacting classes of nuclear envelope-associated coiled-coil proteins are required for the tissue-specific nuclear envelope targeting of arabidopsis rangap. | ran gtpase plays essential roles in multiple cellular processes, including nucleocytoplasmic transport, spindle formation, and postmitotic nuclear envelope (ne) reassembly. the cytoplasmic ran gtpase activating protein rangap is critical to establish a functional rangtp/rangdp gradient across the ne and is associated with the outer surface of the ne in metazoan and higher plant cells. arabidopsis thaliana rangap association with the root tip ne requires a family of likely plant-specific nucleopo ... | 2008 | 18591351 |
| arabidopsis dreb2a-interacting proteins function as ring e3 ligases and negatively regulate plant drought stress-responsive gene expression. | the dehydration-responsive element binding protein2a (dreb2a) transcription factor controls water deficit-inducible gene expression and requires posttranslational modification for its activation. the activation mechanism is not well understood; however, the stability of this protein in the nucleus was recently found to be important for its activation. here, we report the isolation of arabidopsis thaliana dreb2a-interacting protein1 (drip1) and drip2, c3hc4 ring domain-containing proteins that in ... | 2008 | 18552202 |
| pur4 mutations are lethal to the male, but not the female, gametophyte and affect sporophyte development in arabidopsis. | purine metabolism is crucial in living cells and involves three complex pathways in plants: the de novo synthesis, the salvage, and the degradation pathways. the relative importance of each pathway in plant development and reproduction, however, is still unclear. we identified two t-dna insertions in the arabidopsis (arabidopsis thaliana) pur4 gene (at1g74260) that encodes formylglycinamidine ribonucleotide synthase (ec 6.3.5.3), the fourth enzyme in the de novo purine biosynthesis pathway. the ... | 2008 | 18441219 |
| the pentratricopeptide repeat protein delayed greening1 is involved in the regulation of early chloroplast development and chloroplast gene expression in arabidopsis. | an arabidopsis (arabidopsis thaliana) mutant that exhibited a delayed greening phenotype (dg1) was isolated from a population of activation-tagged arabidopsis lines. young, inner leaves of dg1 mutants were initially very pale, but gradually greened and mature outer leaves, more than 3 weeks old, appeared similar to those of wild-type plants. sequence and transcription analyses showed that dg1 encodes a chloroplast protein consisting of eight pentratricopeptide repeat domains and that its express ... | 2008 | 18400937 |
| reduction of plastid-localized carbonic anhydrase activity results in reduced arabidopsis seedling survivorship. | carbonic anhydrase (ca; ec 4.2.1.1) catalyzes the interconversion of co2 and hco3(-) and is a major protein constituent of the c3 higher plant chloroplast where it is presumed to play a role in photosynthetic carbon assimilation. in this study, we have used both rna antisense and gene knockout lines to specifically reduce the activity of the chloroplast betaca1 polypeptide (at3g01500) in the model plant arabidopsis (arabidopsis thaliana). although able to germinate, seedling establishment of tra ... | 2008 | 18434607 |
| ruptured pollen grain1, a member of the mtn3/saliva gene family, is crucial for exine pattern formation and cell integrity of microspores in arabidopsis. | during microsporogenesis, the microsporocyte (or microspore) plasma membrane plays multiple roles in pollen wall development, including callose secretion, primexine deposition, and exine pattern determination. however, plasma membrane proteins that participate in these processes are still not well known. here, we report that a new gene, ruptured pollen grain1 (rpg1), encodes a plasma membrane protein and is required for exine pattern formation of microspores in arabidopsis (arabidopsis thaliana) ... | 2008 | 18434608 |
| artificial trans-acting sirnas confer consistent and effective gene silencing. | manipulating gene expression is critical to exploring gene function and a useful tool for altering commercial traits. techniques such as hairpin-based rna interference, virus-induced gene silencing, and artificial micrornas take advantage of endogenous posttranscriptional gene silencing pathways to block translation of designated transcripts. here we present a novel gene silencing method utilizing artificial trans-acting small interfering rnas in arabidopsis (arabidopsis thaliana). replacing the ... | 2008 | 18441221 |
| regulation of dormancy in barley by blue light and after-ripening: effects on abscisic acid and gibberellin metabolism. | white light strongly promotes dormancy in freshly harvested cereal grains, whereas dark and after-ripening have the opposite effect. we have analyzed the interaction of light and after-ripening on abscisic acid (aba) and gibberellin (ga) metabolism genes and dormancy in barley (hordeum vulgare 'betzes'). analysis of gene expression in imbibed barley grains shows that different aba metabolism genes are targeted by white light and after-ripening. of the genes examined, white light promotes the exp ... | 2008 | 18408047 |
| multidimensional fluorescence microscopy of multiple organelles in arabidopsis seedlings. | the isolation of green fluorescent protein (gfp) and the development of spectral variants over the past decade have begun to reveal the dynamic nature of protein trafficking and organelle motility. in planta analyses of this dynamic process have typically been limited to only two organelles or proteins at a time in only a few cell types. | 2008 | 18489765 |
| ibmads1 (ipomoea batatas mads-box 1 gene) is involved in tuberous root initiation in sweet potato (ipomoea batatas). | the tuberization mechanism of sweet potato (ipomoea batatas) has long been studied using various approaches. morphological data have revealed that the tuberizing events result from the activation of the cambium, followed by cell proliferation. however, uncertainties still remain regarding the regulators participating in this signal-transduction pathway. an attempt was made to characterize the role of one mads-box transcription factor, which was preferentially expressed in sweet potato roots at t ... | 2008 | 18463111 |
| the evolution of modularity in bacterial metabolic networks. | deciphering the modular organization of metabolic networks and understanding how modularity evolves have attracted tremendous interest in recent years. here, we present a comprehensive large scale characterization of modularity across the bacterial tree of life, systematically quantifying the modularity of the metabolic networks of >300 bacterial species. three main determinants of metabolic network modularity are identified. first, network size is an important topological determinant of network ... | 2008 | 18460604 |
| john bryant takes a closer look at some of this month's original articles. | | 2008 | 18426808 |
| the scientific roots of modern plant biotechnology. | | 2008 | 18515500 |
| signals derived from yabby gene activities in organ primordia regulate growth and partitioning of arabidopsis shoot apical meristems. | shoot apical meristems (sams) are self-sustaining groups of cells responsible for the ordered initiation of all aerial plant tissues, including stems and lateral organs. the precise coordination of these processes argues for crosstalk between the different sam domains. the products of yabby (yab) genes are limited to the organ primordium domains, which are situated at the periphery of all sams and which are separated by a margin of three to seven cells from the central meristem zone marked by wu ... | 2008 | 18469164 |
| a transporter regulating silicon distribution in rice shoots. | rice (oryza sativa) accumulates very high concentrations of silicon (si) in the shoots, and the deposition of si as amorphous silica helps plants to overcome biotic and abiotic stresses. here, we describe a transporter, lsi6, which is involved in the distribution of si in the shoots. lsi6 belongs to the nodulin-26 intrinsic protein iii subgroup of aquaporins and is permeable to silicic acid. lsi6 is expressed in the leaf sheath and leaf blades as well as in the root tips. cellular localization s ... | 2008 | 18515498 |
| dual effects of mir156-targeted spl genes and cyp78a5/kluh on plastochron length and organ size in arabidopsis thaliana. | leaves of flowering plants are produced from the shoot apical meristem at regular intervals, with the time that elapses between the formation of two successive leaf primordia defining the plastochron. we have identified two genetic axes affecting plastochron length in arabidopsis thaliana. one involves microrna156 (mir156), which targets a series of squamosa promoter binding protein-like (spl) genes. in situ hybridization studies and misexpression experiments demonstrate that mir156 is a quantit ... | 2008 | 18492871 |
| dual fatty acyl modification determines the localization and plasma membrane targeting of cbl/cipk ca2+ signaling complexes in arabidopsis. | arabidopsis thaliana calcineurin b-like proteins (cbls) interact specifically with a group of cbl-interacting protein kinases (cipks). cbl/cipk complexes phosphorylate target proteins at the plasma membrane. here, we report that dual lipid modification is required for cbl1 function and for localization of this calcium sensor at the plasma membrane. first, myristoylation targets cbl1 to the endoplasmic reticulum. second, s-acylation is crucial for endoplasmic reticulum-to-plasma membrane traffick ... | 2008 | 18502848 |
| mild reductions in mitochondrial citrate synthase activity result in a compromised nitrate assimilation and reduced leaf pigmentation but have no effect on photosynthetic performance or growth. | transgenic tomato (solanum lycopersicum) plants, expressing a fragment of the mitochondrial citrate synthase gene in the antisense orientation and exhibiting mild reductions in the total cellular activity of this enzyme, displayed essentially no visible phenotypic alteration from the wild type. a more detailed physiological characterization, however, revealed that although these plants were characterized by relatively few changes in photosynthetic parameters they displayed a decreased relative f ... | 2008 | 18359839 |
| cell wall modifications in arabidopsis plants with altered alpha-l-arabinofuranosidase activity. | although cell wall remodeling is an essential feature of plant growth and development, the underlying molecular mechanisms are poorly understood. this work describes the characterization of arabidopsis (arabidopsis thaliana) plants with altered expression of araf1, a bifunctional alpha-l-arabinofuranosidase/beta-d-xylosidase (at3g10740) belonging to family 51 glycosyl-hydrolases. araf1 was localized in several cell types in the vascular system of roots and stems, including xylem vessels and pare ... | 2008 | 18344421 |
| global characterization of cell-specific gene expression through fluorescence-activated sorting of nuclei. | we describe a simple and highly effective means for global identification of genes that are expressed within specific cell types within complex tissues. it involves transgenic expression of nuclear-targeted green fluorescent protein in a cell-type-specific manner. the fluorescent nuclei are then purified from homogenates by fluorescence-activated sorting, and the rnas employed as targets for microarray hybridization. we demonstrate the validity of the approach through the identification of 12 ge ... | 2008 | 18354040 |
| decrease in manganese superoxide dismutase leads to reduced root growth and affects tricarboxylic acid cycle flux and mitochondrial redox homeostasis. | superoxide dismutases (sods) are key components of the plant antioxidant defense system. while plastidic and cytosolic isoforms have been extensively studied, the importance of mitochondrial sod at a cellular and whole-plant level has not been established. to address this, transgenic arabidopsis (arabidopsis thaliana) plants were generated in which expression of atmsd1, encoding the mitochondrial manganese (mn)sod, was suppressed by antisense. the strongest antisense line showed retarded root gr ... | 2008 | 18337490 |
| amino acid substitutions in homologs of the stay-green protein are responsible for the green-flesh and chlorophyll retainer mutations of tomato and pepper. | color changes often accompany the onset of ripening, leading to brightly colored fruits that serve as attractants to seed-dispersing organisms. in many fruits, including tomato (solanum lycopersicum) and pepper (capsicum annuum), there is a sharp decrease in chlorophyll content and a concomitant increase in the synthesis of carotenoids as a result of the conversion of chloroplasts into chromoplasts. the green-flesh (gf) and chlorophyll retainer (cl) mutations of tomato and pepper, respectively, ... | 2008 | 18359841 |
| construction of a functional cmp-sialic acid biosynthesis pathway in arabidopsis. | previous studies have reported that plants contain negligible amounts of free or protein-bound n-acetylneuraminic acid (neu5ac). this is a major disadvantage for the use of plants as a biopharmaceutical expression system, since n-glycans with terminal neu5ac residues are important for the biological activities and half-lives of recombinant therapeutic glycoproteins in humans. for the synthesis of neu5ac-containing n-glycans, plants have to acquire the ability to synthesize neu5ac and its nucleot ... | 2008 | 18326787 |
| hairpin rnas derived from rna polymerase ii and polymerase iii promoter-directed transgenes are processed differently in plants. | rna polymerase iii (pol iii) as well as pol ii (35s) promoters are able to drive hairpin rna (hprna) expression and induce target gene silencing in plants. sirnas of 21 nt are the predominant species in a 35s pol ii line, whereas 24- and/or 22-nucleotide (nt) sirnas are produced by a pol iii line. the 35s line accumulated the loop of the hprna, in contrast to full-length hprna in the pol iii line. these suggest that pol ii and pol iii-transcribed hprnas are processed by different pathways. one p ... | 2008 | 18367720 |
| the snf1-type serine-threonine protein kinase sapk4 regulates stress-responsive gene expression in rice. | plants respond to extracellularly perceived abiotic stresses such as low temperature, drought, and salinity by activation of complex intracellular signaling cascades that regulate acclimatory biochemical and physiological changes. protein kinases are major signal transduction factors that have a central role in mediating acclimation to environmental changes in eukaryotic organisms. in this study, we characterized the function of the sucrose nonfermenting 1-related protein kinase2 (snrk2) sapk4 i ... | 2008 | 18442365 |
| a systematic survey in arabidopsis thaliana of transcription factors that modulate circadian parameters. | plant circadian systems regulate various biological processes in harmony with daily environmental changes. in arabidopsis thaliana, the underlying clock mechanism is comprised of multiple integrated transcriptional feedbacks, which collectively lead to global patterns of rhythmic gene expression. the transcriptional networks are essential within the clock itself and in its output pathway. | 2008 | 18426557 |
| a spatial dissection of the arabidopsis floral transcriptome by mpss. | we have further characterized floral organ-localized gene expression in the inflorescence of arabidopsis thaliana by comparison of massively parallel signature sequencing (mpss) data. six libraries of rna sequence tags from immature inflorescence tissues were constructed and matched to their respective loci in the annotated arabidopsis genome. these signature libraries survey the floral transcriptome of wild-type tissue as well as the floral homeotic mutants, apetala1, apetala3, agamous, a super ... | 2008 | 18426585 |
| cu/zn superoxide dismutases in developing cotton fibers: evidence for an extracellular form. | hydrogen peroxide and other reactive oxygen species are important signaling molecules in diverse physiological processes. previously, we discovered superoxide dismutase (sod) activity in extracellular protein preparations from fiber-bearing cotton (gossypium hirsutum l.) seeds. we show here, based on immunoreactivity, that the enzyme is a cu/zn-sod (csd). immunogold localization shows that csd localizes to secondary cell walls of developing cotton fibers. five cotton csd cdnas were cloned from c ... | 2008 | 18425534 |
| overexpression of mtdna-associated atwhy2 compromises mitochondrial function. | stwhy1, a member of the plant-specific whirly single-stranded dna-binding protein family, was first characterized as a transcription factor involved in the activation of the nuclear pr-10a gene following defense-related stress in potato. in arabidopsis thaliana, whirlies have recently been shown to be primarily localized in organelles. two representatives of the family, atwhy1 and atwhy3 are imported into plastids while atwhy2 localizes to mitochondria. their function in organelles is currently ... | 2008 | 18423020 |
| the ibr5 phosphatase promotes arabidopsis auxin responses through a novel mechanism distinct from tir1-mediated repressor degradation. | in arabidopsis, indole-3-butyric acid response5 (ibr5), a putative dual-specificity protein phosphatase, is a positive regulator of auxin response. mutations in ibr5 result in decreased plant height, defective vascular development, increased leaf serration, fewer lateral roots, and resistance to the phytohormones auxin and abscisic acid. however, the pathways through which ibr5 influences auxin responses are not fully understood. | 2008 | 18423007 |
| ornithine-delta-aminotransferase is essential for arginine catabolism but not for proline biosynthesis. | like many other plant species, arabidopsis uses arginine (arg) as a storage and transport form of nitrogen, and proline (pro) as a compatible solute in the defence against abiotic stresses causing water deprivation. arg catabolism produces ornithine (orn) inside mitochondria, which was discussed controversially as a precursor for pro biosynthesis, alternative to glutamate (glu). | 2008 | 18419821 |
| arabidopsis thaliana outer ovule integument morphogenesis: ectopic expression of knat1 reveals a compensation mechanism. | the arabidopsis outer ovule integument is a simple two-cell layered structure that grows around the developing embryo and develops into the outer layer of the seed coat. as one of the functions of the seed coat is the protection of the plant embryo, the outer ovule integument is an example for a plant organ whose morphogenesis has to be precisely regulated. | 2008 | 18410683 |
| the supernumerary chromosome of nectria haematococca that carries pea-pathogenicity-related genes also carries a trait for pea rhizosphere competitiveness. | fungi are found in a wide range of environments, and the ecological and host diversity of the fungus nectria haematococca has been shown to be due in part to unique genes on different supernumerary chromosomes. these chromosomes have been called "conditionally dispensable" (cd) since they are not needed for axenic growth but are important for expanding the host range of individual isolates. from a biological perspective, the cd chromosomes can be compared to bacterial plasmids that carry unique ... | 2008 | 18408061 |
| ftir study of the photoinduced processes of plant phytochrome phya using isotope-labeled bilins and density functional theory calculations. | fourier transform infrared spectroscopy was used to analyze the chromophore structure in the parent states pr and pfr of plant phytochrome phya and the respective photoproducts lumi-r and lumi-f. the spectra were obtained from phya adducts assembled with either uniformly or selectively isotope-labeled phytochromobilin and phycocyanobilin. the interpretation of the experimental spectra is based on the spectra of chromophore models calculated by density functional theory. global (13)c-labeling of ... | 2008 | 18390618 |
| an integrated genetic, genomic and systems approach defines gene networks regulated by the interaction of light and carbon signaling pathways in arabidopsis. | light and carbon are two important interacting signals affecting plant growth and development. the mechanism(s) and/or genes involved in sensing and/or mediating the signaling pathways involving these interactions are unknown. this study integrates genetic, genomic and systems approaches to identify a genetically perturbed gene network that is regulated by the interaction of carbon and light signaling in arabidopsis. | 2008 | 18387196 |
| knox lost the ox: the arabidopsis knatm gene defines a novel class of knox transcriptional regulators missing the homeodomain. | three amino acid loop extension (tale) homeodomain transcriptional regulators play a central role in plant and animal developmental programs. plant knotted1-like homeobox (knox) and animal myeloid ecotropic viral integration site (meis) proteins share a tale homeodomain and a meinox (meis-knox) domain, suggesting that an ancestral meinox-tale protein predates the divergence of plants from fungi and animals. in this study, we identify and characterize the arabidopsis thaliana knatm gene, which en ... | 2008 | 18398054 |
| analysis of the arabidopsis histidine kinase athk1 reveals a connection between vegetative osmotic stress sensing and seed maturation. | to cope with water stress, plants must be able to effectively sense, respond to, and adapt to changes in water availability. the arabidopsis thaliana plasma membrane his kinase athk1 has been suggested to act as an osmosensor that detects water stress and initiates downstream responses. here, we provide direct genetic evidence that athk1 not only is involved in the water stress response during early vegetative stages of plant growth but also plays a unique role in the regulation of desiccation p ... | 2008 | 18441212 |
| rebelote, squint, and ultrapetala1 function redundantly in the temporal regulation of floral meristem termination in arabidopsis thaliana. | in arabidopsis thaliana, flowers are determinate, showing a fixed number of whorls. here, we report on three independent genes, a novel gene rebelote (rbl; protein of unknown function), squint (sqn; a cyclophilin), and ultrapetala1 (ult1; a putative transcription factor) that redundantly influence floral meristem (fm) termination. their mutations, combined with each other or with crabs claw, the genetic background in which they were isolated, trigger a strong fm indeterminacy with reiterations o ... | 2008 | 18441215 |
| early gene duplication within chloroplastida and its correspondence with relocation of starch metabolism to chloroplasts. | the endosymbiosis event resulting in the plastid of photosynthetic eukaryotes was accompanied by the appearance of a novel form of storage polysaccharide in rhodophyceae, glaucophyta, and chloroplastida. previous analyses indicated that starch synthesis resulted from the merging of the cyanobacterial and the eukaryotic storage polysaccharide metabolism pathways. we performed a comparative bioinformatic analysis of six algal genome sequences to investigate this merger. specifically, we analyzed t ... | 2008 | 18245855 |
| iron-induced turnover of the arabidopsis iron-regulated transporter1 metal transporter requires lysine residues. | iron is an essential micronutrient but is toxic if accumulated at high levels. thus, iron uptake and distribution in plants are controlled by precise regulatory mechanisms. iron-regulated transporter1 (irt1) is the major high affinity iron transporter responsible for iron uptake from the soil in arabidopsis (arabidopsis thaliana). previously, we showed that irt1 is subject to posttranscriptional regulation; when expressed from the constitutive cauliflower mosaic virus 35s promoter, irt1 protein ... | 2008 | 18305211 |
| the gene for the p-subunit of glycine decarboxylase from the c4 species flaveria trinervia: analysis of transcriptional control in transgenic flaveria bidentis (c4) and arabidopsis (c3). | glycine decarboxylase (gdc) plays an important role in the photorespiratory metabolism of plants. gdc is composed of four subunits (p, h, l, and t) with the p-subunit (gldp) serving as the actual decarboxylating unit. in c(3) plants, gdc can be found in all photosynthetic cells, whereas in leaves of c(3)-c(4) intermediate and c(4) species its occurrence is restricted to bundle-sheath cells. the specific expression of gldp in bundle-sheath cells might have constituted a biochemical starting point ... | 2008 | 18305210 |