| small ubiquitin-like modifier proteases overly tolerant to salt1 and -2 regulate salt stress responses in arabidopsis. | understanding salt stress signaling is key to producing salt-tolerant crops. the small ubiquitin-like modifier (sumo) is a crucial regulator of signaling proteins in eukaryotes. attachment of sumo onto substrates is reversible, and sumo proteases, which specifically cleave the sumo-substrate linkages, play a vital regulatory role during sumoylation. we have identified two sumo proteases, overly tolerant to salt1 (ots1) and ots2, which are localized in the nucleus and act redundantly to regulate ... | 2008 | 18849491 |
| recent advances in the analysis of biological particles by capillary electrophoresis. | this review covers research papers published in the years 2005-2007 that describe the application of capillary electrophoresis to the analysis of biological particles such as whole cells, subcellular organelles, viruses and microorganisms. | 2008 | 18576409 |
| mutation of a rice gene encoding a phenylalanine biosynthetic enzyme results in accumulation of phenylalanine and tryptophan. | two distinct biosynthetic pathways for phe in plants have been proposed: conversion of prephenate to phe via phenylpyruvate or arogenate. the reactions catalyzed by prephenate dehydratase (pdt) and arogenate dehydratase (adt) contribute to these respective pathways. the mtr1 mutant of rice (oryza sativa) manifests accumulation of phe, trp, and several phenylpropanoids, suggesting a link between the synthesis of phe and trp. here, we show that the mtr1 mutant gene (mtr1-d) encodes a form of rice ... | 2008 | 18487352 |
| a myb transcription factor regulates very-long-chain fatty acid biosynthesis for activation of the hypersensitive cell death response in arabidopsis. | plant immune responses to pathogen attack include the hypersensitive response (hr), a form of programmed cell death occurring at invasion sites. we previously reported on arabidopsis thaliana myb30, a transcription factor that acts as a positive regulator of a cell death pathway conditioning the hr. here, we show by microarray analyses of arabidopsis plants misexpressing myb30 that the genes encoding the four enzymes forming the acyl-coa elongase complex are putative myb30 targets. the acyl-coa ... | 2008 | 18326828 |
| gxysba abc transporter of agrobacterium tumefaciens and its role in sugar utilization and vir gene expression. | monosaccharides available in the extracellular milieu of agrobacterium tumefaciens can be transported into the cytoplasm, or via the periplasmic sugar binding protein, chve, play a critical role in controlling virulence gene expression. the chve-mmsab abc transporter is involved in the utilization of a wide range of monosaccharide substrates but redundant transporters are likely given the ability of a chve-mmsab deletion strain to grow, albeit more slowly, in the presence of particular monosacch ... | 2014 | 24957625 |
| pepper suppressor of the g2 allele of skp1 interacts with the receptor-like cytoplasmic kinase1 and type iii effector avrbst and promotes the hypersensitive cell death response in a phosphorylation-dependent manner. | xanthomonas campestris pv vesicatoria type iii effector protein, avrbst, triggers hypersensitive cell death in pepper (capsicum annuum). here, we have identified the pepper sgt1 (for suppressor of the g2 allele of skp1) as a host interactor of avrbst and also the pepper pik1 (for receptor-like cytoplasmic kinase1). pik1 specifically phosphorylates sgt1 and avrbst in vitro. avrbst specifically binds to the chord-containing protein and sgt1 domain of sgt1, resulting in the inhibition of pik1-media ... | 2014 | 24686111 |
| the mosaic type iv secretion systems. | escherichia coli and other gram-negative and -positive bacteria employ type iv secretion systems (t4sss) to translocate dna and protein substrates, generally by contact-dependent mechanisms, to other cells. the t4sss functionally encompass two major subfamilies, the conjugation systems and the effector translocators. the conjugation systems are responsible for interbacterial transfer of antibiotic resistance genes, virulence determinants, and genes encoding other traits of potential benefit to t ... | 2016 | 27735785 |
| development of a microemulsion formulation for antimicrobial seca inhibitors. | in our previous study, we have identified five antimicrobial small molecules via structure based design, which inhibit seca of candidatus liberibacter asiaticus (las). seca is a critical protein translocase atpase subunit and is involved in pre-protein translocation across and integration into the cellular membrane in bacteria. in this study, eleven compounds were identified using similarity search method based on the five lead seca inhibitors identified previously. the identified seca inhibitor ... | 2016 | 26963811 |
| molecular characterisation of the strubbelig-receptor family of genes encoding putative leucine-rich repeat receptor-like kinases in arabidopsis thaliana. | receptor-like kinases are a prominent class of surface receptors that regulate many aspects of the plant life cycle. despite recent advances the function of most receptor-like kinases remains elusive. therefore, it is paramount to investigate these receptors. the task is complicated by the fact that receptor-like kinases belong to a large monophyletic family with many sub-clades. in general, functional analysis of gene family members by reverse genetics is often obscured by several issues, such ... | 2007 | 17397538 |
| characterization of the sp11/scr high-affinity binding site involved in self/nonself recognition in brassica self-incompatibility. | in brassica self-incompatibility, the recognition of self/nonself pollen grains, is controlled by the s-locus, which encodes three highly polymorphic proteins: s-locus receptor kinase (srk), s-locus protein 11 (sp11; also designated s-locus cys-rich protein), and s-locus glycoprotein (slg). sp11, located in the pollen coat, determines pollen s-haplotype specificity, whereas srk, located on the plasma membrane of stigmatic papilla cells, determines stigmatic s-haplotype specificity. slg shares si ... | 2007 | 17220204 |
| identification of an ospr10a promoter region responsive to salicylic acid. | orysa sativa pathogenesis-related protein 10a (ospr10a) was induced by pathogens, salicylic acid (sa), jasmonic acid (ja), ethephon, abscisic acid (aba), and nacl. we tried to analyze the ospr10a promoter to investigate the transcriptional regulation of ospr10a by sa. we demonstrated the inducibility of ospr10a promoter by sa using transgenic arabidopsis carrying ospr10a:gfp as well as by transient expression assays in rice. to further identify the promoter region responsible for its induction b ... | 2008 | 18193274 |
| barriers to intron promiscuity in bacteria. | | 2000 | 10986228 |
| the arabidopsis los5/aba3 locus encodes a molybdenum cofactor sulfurase and modulates cold stress- and osmotic stress-responsive gene expression. | to understand low temperature and osmotic stress signaling in plants, we isolated and characterized two allelic arabidopsis mutants, los5-1 and los5-2, which are impaired in gene induction by cold and osmotic stresses. expression of rd29a-luc (the firefly luciferase reporter gene under the control of the stress-responsive rd29a promoter) in response to cold and salt/drought is reduced in the los5 mutants, but the response to abscisic acid (aba) remains unaltered. rna gel blot analysis indicates ... | 2001 | 11549764 |
| improvement of coenzyme q10 production: mutagenesis induced by high hydrostatic pressure treatment and optimization of fermentation conditions. | coenzyme q10 (coq10, ubiquinone), a potent antioxidative dietary supplement, was produced by submerged fermentation using agrobacterium tumefaciens instead of chemical synthesis or solvent extraction. agrobacterium tumefaciens 1.2554 was subjected to mutagenesis using a series of treatments including high hydrostatic pressure (hhp) treatment, uv irradiation, and diethyl sulfate (des) treatment to obtain mutant strains showing higher coq10 production than wild-type strains. a mutant strain pk38 w ... | 2012 | 23091351 |
| constitutive expression of the cold-regulated arabidopsis thaliana cor15a gene affects both chloroplast and protoplast freezing tolerance. | cold acclimation in plants is associated with the expression of cor (cold-regulated) genes that encode polypeptides of unknown function. it has been widely speculated that products of these genes might have roles in freezing tolerance. here we provide direct evidence in support of this hypothesis. we show that constitutive expression of cor15a, a cold-regulated gene of arabidopsis thaliana that encodes a chloroplast-targeted polypeptide, enhances the in vivo freezing tolerance of chloroplasts in ... | 1996 | 11038526 |
| a deletion in an indole synthase gene is responsible for the dimboa-deficient phenotype of bxbx maize. | the biosynthesis of dimboa, a pesticidal secondary metabolite of maize, branches off the tryptophan pathway. we have previously demonstrated that indole is the last intermediate common to both the tryptophan and hydroxamic acid pathways. the earliest discovered mutant in the dimboa pathway, bxbx (benzoxazineless), is deficient in the production of dimboa and related compounds. this paper presents evidence that a gene identified by kramer and koziel [kramer, v. c. & koziel, m. g. (1995) plant mol ... | 1997 | 9371848 |
| the arabidopsis hy5 gene encodes a bzip protein that regulates stimulus-induced development of root and hypocotyl. | plant developmental processes are controlled by both endogenous programs and environmental stimuli. as a photomorphogenetic mutant, hy5 of arabidopsis has been isolated and characterized. our detailed characterization has revealed that the mutant is deficient in a variety of stimulus responses, including gravitropic response and waving growth of roots, as well as light-dependent hypocotyl elongation. in the roots and hypocotyl, the hy5 mutation also affects greening and specific cell proliferati ... | 1997 | 9367981 |
| efficient gene tagging in arabidopsis thaliana using a gene trap approach. | large quantities of dna sequence information about plant genes are rapidly accumulating in public databases, but to progress from dna sequence to biological function a mutant allele for each of the genes ideally should be available. here we describe a gene trap construct that allowed us to disrupt transcribed genes with a high efficiency in arabidopsis thaliana. in the t-dna vector used, the expression of a bacterial reporter gene coding for neomycin phosphotransferase ii (nptii) depends on the ... | 1997 | 9356517 |
| epigenetic silencing of rna polymerase i transcription: a role for dna methylation and histone modification in nucleolar dominance. | nucleolar dominance is an epigenetic phenomenon that describes nucleolus formation around rrna genes inherited from only one progenitor of an interspecific hybrid or allopolyploid. the phenomenon is widespread, occurring in plants, insects, amphibians, and mammals, yet its molecular basis remains unclear. we have demonstrated nucleolar dominance in three allotetraploids of the plant genus brassica. in brassica napus, accurately initiated pre-rrna transcripts from one progenitor, brassica rapa ar ... | 1997 | 9284051 |
| characterization of the transposition pattern of the ac element in arabidopsis thaliana using endonuclease i-scei. | we have investigated physical distances and directions of transposition of the maize transposable element ac in arabidopsis thaliana. we prepared a transferred dna (t-dna) construct that carried a non-autonomous derivative of ac with a site for cleavage by endonuclease i-scei (designated dac-i-rs element). another cleavage site was also introduced into the t-dna region outside dac-i-rs. three transgenic arabidopsis plants were generated, each of which had a single copy of the t-dna at a differen ... | 1997 | 11038561 |
| expression of a mutant alpha-zein creates the floury2 phenotype in transgenic maize. | the maize floury2 mutation results in the formation of a soft, starchy endosperm with a reduced amount of prolamin (zein) proteins and twice the lysine content of the wild type. the mutation is semidominant and is associated with small, irregularly shaped protein bodies, elevated levels of a 70-kda chaperone in the endoplasmic reticulum, and a novel 24-kda polypeptide in the zein fraction. the 24-kda polypeptide is a precursor of a 22-kda alpha-zein protein that is not properly processed. the de ... | 1997 | 9192697 |
| a homeobox gene with potential developmental control function in the meristem of the conifer picea abies. | many homeobox genes control essential developmental processes in animals and plants. in this report, we describe the first cdna corresponding to a homeobox gene isolated from a gymnosperm, the hbk1 gene from the conifer picea abies (l.) karst (norway spruce). the sequence shows distinct similarities specifically to the knox (knotted-like homeobox) class of homeobox genes known from different angiosperm plants. the deduced amino acid sequence of hbk1 is strikingly similar within the homeodomain ( ... | 1998 | 9844025 |
| nuclear events in ethylene signaling: a transcriptional cascade mediated by ethylene-insensitive3 and ethylene-response-factor1. | response to the gaseous plant hormone ethylene in arabidopsis requires the ein3/eil family of nuclear proteins. the biochemical function(s) of ein3/eil proteins, however, has remained unknown. in this study, we show that ein3 and eils comprise a family of novel sequence-specific dna-binding proteins that regulate gene expression by binding directly to a primary ethylene response element (pere) related to the tomato e4-element. moreover, we identified an immediate target of ein3, ethylene-respons ... | 1998 | 9851977 |
| inhibition of auxin movement from the shoot into the root inhibits lateral root development in arabidopsis. | in roots two distinct polar movements of auxin have been reported that may control different developmental and growth events. to test the hypothesis that auxin derived from the shoot and transported toward the root controls lateral root development, the two polarities of auxin transport were uncoupled in arabidopsis. local application of the auxin-transport inhibitor naphthylphthalamic acid (npa) at the root-shoot junction decreased the number and density of lateral roots and reduced the free in ... | 1998 | 9847111 |
| nph4, a conditional modulator of auxin-dependent differential growth responses in arabidopsis. | although sessile in nature, plants are able to use a number of mechanisms to modify their morphology in response to changing environmental conditions. differential growth is one such mechanism. despite its importance in plant development, little is known about the molecular events regulating the establishment of differential growth. here we report analyses of the nph4 (nonphototropic hypocotyl) mutants of arabidopsis that suggest that the nph4 protein plays a central role in the modulation of au ... | 1998 | 9847100 |
| a gene encoding proline dehydrogenase is not only induced by proline and hypoosmolarity, but is also developmentally regulated in the reproductive organs of arabidopsis. | the cdna clone erd5 (early responsive to dehydration), isolated from 1-h-dehydrated arabidopsis, encodes a precursor of proline (pro) dehydrogenase (prodh), which is a mitochondrial enzyme involved in the first step of the conversion of pro to glutamic acid. the transcript of the erd5 (prodh) gene was undetectable when plants were dehydrated, but large amounts of transcript accumulated when plants were subsequently rehydrated. accumulation of the transcript was also observed in plants that had b ... | 1998 | 9847097 |
| plant gene silencing regularized. | | 1998 | 9811802 |
| overexpression of 20-oxidase confers a gibberellin-overproduction phenotype in arabidopsis. | in the gibberellin (ga) biosynthesis pathway, 20-oxidase catalyzes the oxidation and elimination of carbon-20 to give rise to c19-gas. all bioactive gas are c19-gas. we have overexpressed a cdna encoding 20-oxidase isolated from arabidopsis seedlings in transgenic arabidopsis plants. these transgenic plants display a phenotype that may be attributed to the overproduction of ga. the phenotype includes a longer hypocotyl, lighter-green leaves, increased stem elongation, earlier flowering, and decr ... | 1998 | 9808721 |
| systematic reverse genetics of transfer-dna-tagged lines of arabidopsis. isolation of mutations in the cytochrome p450 gene superfamily. | we have developed an efficient reverse-genetics protocol that uses expedient pooling and hybridization strategies to identify individual transfer-dna insertion lines from a collection of 6000 independently transformed lines in as few as 36 polymerase chain reactions. we have used this protocol to systematically isolate arabidopsis lines containing insertional mutations in individual cytochrome p450 genes. in higher plants p450 genes encode enzymes that perform an exceptionally wide range of func ... | 1998 | 9808718 |
| the heat-shock element is a functional component of the arabidopsis apx1 gene promoter. | ascorbate peroxidases are important enzymes that detoxify hydrogen peroxide within the cytosol and chloroplasts of plant cells. to better understand their role in oxidative stress tolerance, the transcriptional regulation of the apx1 gene from arabidopsis was studied. the apx1 gene was expressed in all tested organs of arabidopsis; mrna levels were low in roots, leaves, and stems and high in flowers. steady-state mrna levels in leaves or cell suspensions increased after treatment with methyl vio ... | 1998 | 9808745 |
| domains of a transit sequence required for in vivo import in arabidopsis chloroplasts. | nuclear-encoded precursors of chloroplast proteins are synthesized with an amino-terminal cleavable transit sequence, which contains the information for chloroplastic targeting. to determine which regions of the transit sequence are most important for its function, the chloroplast uptake and processing of a full-length ferredoxin precursor and four mutants with deletions in adjacent regions of the transit sequence were analyzed. arabidopsis was used as an experimental system for both in vitro an ... | 1998 | 9765555 |
| metabolism of indole-3-acetic acid in arabidopsis. | the metabolism of indole-3-acetic acid (iaa) was investigated in 14-d-old arabidopsis plants grown in liquid culture. after ruling out metabolites formed as an effect of nonsterile conditions, high-level feeding, and spontaneous interconversions, a simple metabolic pattern emerged. oxindole-3-acetic acid (oxiaa), oxiaa conjugated to a hexose moiety via the carboxyl group, and the conjugates indole-3-acetyl aspartic acid (iaasp) and indole-3-acetyl glutamate (iaglu) were identified by mass spectr ... | 1998 | 9733548 |
| genetic interactions between phytochrome a, phytochrome b, and cryptochrome 1 during arabidopsis development. | single, double, and triple null combinations of arabidopsis mutants lacking the photoreceptors phytochrome (phy) a (phya-201), phyb (phyb-5), and cryptochrome (cry) 1 (hy4-2.23n) were examined for de-etiolation responses in high-fluence red, far-red, blue, and broad-spectrum white light. cotyledon unhooking, unfolding, and expansion, hypocotyl growth, and the accumulation of chlorophylls and anthocyanin in 5-d-old seedlings were measured under each light condition and in the dark. phya was the m ... | 1998 | 9733523 |
| the rotundifolia3 gene of arabidopsis thaliana encodes a new member of the cytochrome p-450 family that is required for the regulated polar elongation of leaf cells. | the polarized processes of cell elongation play a crucial role in morphogenesis of higher plants. we reported previously that the rotundifolia3 (rot3) mutant of arabidopsis has a defect in the polar elongation of leaf cells. in the present study, we isolated two additional alleles with mutations in the rot3 gene. the rot3 gene was cloned by a t-dna-tagging method and isolation of the gene was confirmed by a molecular analysis of three rot3 mutant alleles obtained from different mutagenesis. the ... | 1998 | 9694802 |
| auxin-growth relationships in maize coleoptiles and pea internodes and control by auxin of the tissue sensitivity to auxin | growth of a zone of maize (zea mays l.) coleoptiles and pea (pisum sativum l.) internodes was greatly suppressed when the organ was decapitated or ringed at an upper position with the auxin transport inhibitor n-1-naphthylphthalamic acid (npa) mixed with lanolin. the transport of apically applied 3h-labeled indole-3-acetic acid (iaa) was similarly inhibited by npa. the growth suppressed by npa or decapitation was restored by the iaa mixed with lanolin and applied directly to the zone, and the ma ... | 1998 | 9701602 |
| brittle-1, an adenylate translocator, facilitates transfer of extraplastidial synthesized adp--glucose into amyloplasts of maize endosperms. | amyloplasts of starchy tissues such as those of maize (zea mays l.) function in the synthesis and accumulation of starch during kernel development. adp-glucose pyrophosphorylase (agpase) is known to be located in chloroplasts, and for many years it was generally accepted that agpase was also localized in amyloplasts of starchy tissues. recent aqueous fractionation of young maize endosperm led to the conclusion that 95% of the cellular agpase was extraplastidial, but immunolocalization studies at ... | 1998 | 9701580 |
| control of meristem development by clavata1 receptor kinase and kinase-associated protein phosphatase interactions | the clavata1 (clv1) gene encodes a putative receptor kinase required for the proper balance between cell proliferation and differentiation in arabidopsis shoot and flower meristems. impaired clv1 signaling results in masses of undifferentiated cells at the shoot and floral meristems. although many putative receptor kinases have been identified in plants, the mechanism of signal transduction mediated by plant receptor-like kinases is largely unknown. one potential effector of receptor kinase sign ... | 1998 | 9701578 |
| overexpression of a homeobox gene, let6, reveals indeterminate features in the tomato compound leaf | the cultivated tomato (lycopersicon esculentum) has a unipinnate compound leaf. in the developing leaf primordium, major leaflet initiation is basipetal, and lobe formation and early vascular differentiation are acropetal. we show that engineered alterations in the expression of a tomato homeobox gene, let6, can cause dramatic changes in leaf morphology. the morphological states are variable and unstable and the phenotypes produced indicate that the tomato leaf has an inherent level of indetermi ... | 1998 | 9662520 |
| genetic manipulation of alcohol dehydrogenase levels in ripening tomato fruit affects the balance of some flavor aldehydes and alcohols | tomato (lycopersicon esculentum) plants were transformed with gene constructs containing a tomato alcohol dehydrogenase (adh) cdna (adh 2) coupled in a sense orientation with either the constitutive cauliflower mosaic virus 35s promoter or the fruit-specific tomato polygalacturonase promoter. ripening fruit from plants transformed with the constitutively expressed transgene(s) had a range of adh activities; some plants had no detectable activity, whereas others had significantly higher adh activ ... | 1998 | 9662548 |
| lignin monomer composition is determined by the expression of a cytochrome p450-dependent monooxygenase in arabidopsis. | the phenylpropanoid pathway provides precursors for the biosynthesis of soluble secondary metabolites and lignin in plants. ferulate-5-hydroxylase (f5h) catalyzes an irreversible hydroxylation step in this pathway that diverts ferulic acid away from guaiacyl lignin biosynthesis and toward sinapic acid and syringyl lignin. this fact led us to postulate that f5h was a potential regulatory step in the determination of lignin monomer composition. to test this hypothesis, we have used arabidopsis to ... | 1998 | 9618461 |
| overexpression of iron superoxide dismutase in transformed poplar modifies the regulation of photosynthesis at low co2 partial pressures or following exposure to the prooxidant herbicide methyl viologen. | chloroplast-targeted overexpression of an fe superoxide dismutase (sod) from arabidopsis thaliana resulted in substantially increased foliar sod activities. ascorbate peroxidase, glutathione reductase, and monodehydroascorbate reductase activities were similar in the leaves from all of the lines, but dehydroascorbate reductase activity was increased in the leaves of the fesod transformants relative to untransformed controls. foliar h2o2, ascorbate, and glutathione contents were comparable in all ... | 1998 | 9625709 |
| a myb homologue, atr1, activates tryptophan gene expression in arabidopsis. | in arabidopsis thaliana, tryptophan pathway genes are induced in response to starvation, wounding, and pathogen attack, resulting in increased production of tryptophan and secondary metabolites important for development and defense. the arabidopsis tryptophan pathway therefore provides an ideal system for elucidating how environmental stimuli are transduced into changes in plant gene expression. to characterize the factors that regulate the first gene in the pathway, asa1, which is the key point ... | 1998 | 9576939 |
| mutation in the arabidopsis pasticcino1 gene, which encodes a new fk506-binding protein-like protein, has a dramatic effect on plant development. | the pasticcino (pas) mutants of arabidopsis thaliana are a new class of plant developmental mutants; members of this class show ectopic cell proliferation in cotyledons, extra layers of cells in the hypocotyl, and an abnormal apical meristem. this phenotype is correlated with both cell division and cell elongation defects. there are three complementation groups of pas mutants (pas1, pas2, and pas3, with, respectively 2, 1, and 4 alleles). here we describe in more detail the pas1-1 allele, which ... | 1998 | 9566922 |
| use of an oxygen-insensitive microscale biosensor for methane to measure methane concentration profiles in a rice paddy. | an oxygen-insensitive microscale biosensor for methane was constructed by furnishing a previously described biosensor with an oxygen guard. the guard consisted of a glass capillary containing heterotrophic bacteria, which consumed oxygen diffusing through the tip membrane, thus preventing it from diffusing into the methane-sensing unit. oxygen microprofiles were measured through the oxygen guard capillary, demonstrating the principle and limitations of the method. when the tip of the guard capil ... | 1998 | 16349527 |
| phosphate availability affects the thylakoid lipid composition and the expression of sqd1, a gene required for sulfolipid biosynthesis in arabidopsis thaliana. | photosynthetic membranes of higher plants contain specific nonphosphorous lipids like the sulfolipid sulfoquinovosyl diacylglycerol in addition to the ubiquitous phospholipid phosphatidylglycerol. in bacteria, an environmental factor that drastically affects thylakoid lipid composition appears to be the availability of phosphate. accordingly, we discovered an increase in the relative amount of sulfolipid and a concomitant decrease in phosphatidylglycerol in arabidopsis thaliana grown on medium w ... | 1998 | 9465123 |
| the arabidopsis cullin atcul1 is modified by the ubiquitin-related protein rub1. | the ubiquitin-like protein rub1 is conjugated to target proteins by a mechanism similar to that of ubiquitin conjugation. genetic studies in arabidopsis thaliana have implicated the rub-conjugation pathway in auxin response. the first step in the pathway is rub activation by a bipartite enzyme composed of the axr1 and ecr1 proteins. ubiquitin activation is an atp-dependent process that involves the formation of an amp-ubiquitin intermediate. here we show that rub activation by axr1-ecr1 also inv ... | 1999 | 10611386 |
| overexpression of thioredoxin h leads to enhanced activity of starch debranching enzyme (pullulanase) in barley grain. | biochemically active wheat thioredoxin h has been overexpressed in the endosperm of transgenic barley grain. two dna constructs containing the wheat thioredoxin h gene (wtrxh) were used for transformation; each contained wtrxh fused to an endosperm-specific b(1)-hordein promoter either with or without a signal peptide sequence for targeting to the protein body. twenty-two stable, independently transformed regenerable lines were obtained by selecting with the herbicide bialaphos to test for the p ... | 1999 | 10588758 |
| non-aug initiation of agamous mrna translation in arabidopsis thaliana. | the mads box organ identity gene agamous (ag) controls several steps during arabidopsis thaliana flower development. ag cdna contains an open reading frame that lacks an atg triplet to function as the translation initiation codon, and the actual amino terminus of the ag protein remains uncharacterized. we have considered the possibility that ag translation can be initiated at a non-aug codon. two possible non-aug initiation codons, cug and acg, are present in the 5' region of ag mrna preceding t ... | 1999 | 10567575 |
| both phya and phyb mediate light-imposed repression of phya gene expression in arabidopsis. | the negatively photoregulated phya gene has a complex promoter structure in arabidopsis, with three active transcription start sites. to identify the photoreceptors responsible for regulation of this gene, and to assess the relative roles of the three transcription start sites, we analyzed the changes in phya transcript levels in wild-type and photoreceptor mutant seedlings under various irradiation conditions. continuous far-red or red light exposures each induced a significant decline in trans ... | 1999 | 10594107 |
| auxin is required for leaf vein pattern in arabidopsis. | to investigate possible roles of polar auxin transport in vein patterning, cotyledon and leaf vein patterns were compared for plants grown in medium containing polar auxin transport inhibitors (n-1-naphthylphthalamic acid, 9-hydroxyfluorene-9-carboxylic acid, and 2,3,5-triiodobenzoic acid) and in medium containing a less well-characterized inhibitor of auxin-mediated processes, 2-(p-chlorophynoxy)-2-methylpropionic acid. cotyledon vein pattern was not affected by any inhibitor treatments, althou ... | 1999 | 10594105 |
| developmental and wound-, cold-, desiccation-, ultraviolet-b-stress-induced modulations in the expression of the petunia zinc finger transcription factor gene zpt2-2 | the zpt2-2 gene belongs to the epf gene family in petunia (petunia hybrida), which encodes proteins with tfiiia-type zinc-finger dna-binding motifs. to elucidate a possible function for zpt2-2, we analyzed its pattern of expression in relation to different developmental and physiological stress signals. the activity of the zpt2-2 promoter was analyzed using a firefly luciferase (luc) reporter gene, allowing for continuous measurements of transgene activity in planta. we show that zpt2-2::luc is ... | 1999 | 10594102 |
| pickle is a chd3 chromatin-remodeling factor that regulates the transition from embryonic to vegetative development in arabidopsis. | the life cycle of angiosperms is punctuated by a dormant phase that separates embryonic and postembryonic development of the sporophyte. in the pickle (pkl) mutant of arabidopsis, embryonic traits are expressed after germination. the penetrance of the pkl phenotype is strongly enhanced by inhibitors of gibberellin biosynthesis. map-based cloning of the pkl locus revealed that it encodes a chd3 protein. chd3 proteins have been implicated as chromatin-remodeling factors involved in repression of t ... | 1999 | 10570159 |
| oryza sativa psk gene encodes a precursor of phytosulfokine-alpha, a sulfated peptide growth factor found in plants. | phytosulfokine-alpha [psk-alpha, tyr(so(3)h)-ile-tyr(so(3)h)-thr-gln], a sulfated mitogenic peptide found in plants, strongly promotes proliferation of plant cells in culture at very low concentrations. oryza sativa psk (ospsk) cdna encoding a psk-alpha precursor has been isolated. the cdna is 725 base pairs long, and the 89-aa product, preprophytosulfokine, has a 22-aa hydrophobic region that resembles a cleavable leader peptide at its nh(2) terminus. the psk-alpha sequence occurs only once wit ... | 1999 | 10557360 |
| a small asparagine-rich protein required for s-allele-specific pollen rejection in nicotiana. | although s-locus rnases (s-rnases) determine the specificity of pollen rejection in self-incompatible (si) solanaceous plants, they alone are not sufficient to cause s-allele-specific pollen rejection. to identify non-s-rnase sequences that are required for pollen rejection, a nicotiana alata cdna library was screened by differential hybridization. one clone, designated ht, hybridized strongly to rna from n. alata styles but not to rna from nicotiana plumbaginifolia, a species known to lack one ... | 1999 | 10557358 |
| a re-evaluation of the relative roles of two invertases, incw2 and ivr1, in developing maize kernels and other tissues. | we have examined the relative abundance and distribution of the transcripts and protein products of a cell wall gene (incw2) and a soluble invertase gene (ivr1) to better understand their relative roles during maize (zea mays l.) kernel development. in developing kernels the steady-state levels of incw2 transcript increased dramatically from 0 to 12 d after pollination, while ivr1 transcript, in contrast to a previous report, was undetectable. consistent with the rna expression data, the ivr1 pr ... | 1999 | 10557252 |
| axr1 acts after lateral bud formation to inhibit lateral bud growth in arabidopsis. | the axr1 gene of arabidopsis is required for many auxin responses. the highly branched shoot phenotype of mature axr1 mutant plants has been taken as genetic evidence for a role of auxin in the control of shoot branching. we compared the development of lateral shoots in wild-type columbia and axr1-12 plants. in the wild type, the pattern of lateral shoot development depends on the developmental stage of the plant. during prolonged vegetative growth, axillary shoots arise and develop in a basal-a ... | 1999 | 10557232 |
| brassinosteroid-insensitive dwarf mutants of arabidopsis accumulate brassinosteroids. | seven dwarf mutants resembling brassinosteroid (br)-biosynthetic dwarfs were isolated that did not respond significantly to the application of exogenous brs. genetic and molecular analyses revealed that these were novel alleles of bri1 (brassinosteroid-insensitive 1), which encodes a receptor kinase that may act as a receptor for brs or be involved in downstream signaling. the results of morphological and molecular analyses indicated that these represent a range of alleles from weak to null. the ... | 1999 | 10557222 |
| genetic ablation of root cap cells in arabidopsis. | the root cap is increasingly appreciated as a complex and dynamic plant organ. root caps sense and transmit environmental signals, synthesize and secrete small molecules and macromolecules, and in some species shed metabolically active cells. however, it is not known whether root caps are essential for normal shoot and root development. we report the identification of a root cap-specific promoter and describe its use to genetically ablate root caps by directing root cap-specific expression of a ... | 1999 | 10536027 |
| the protein kinase ck2 is involved in regulation of circadian rhythms in arabidopsis. | a wide range of processes in plants, including expression of certain genes, is regulated by endogenous circadian rhythms. the circadian clock-associated 1 (cca1) and the late elongated hypocotyl (lhy) proteins have been shown to be closely associated with clock function in arabidopsis thaliana. the protein kinase ck2 can interact with and phosphorylate cca1, but its role in the regulation of the circadian clock remains unknown. here we show that plants overexpressing ckb3, a regulatory subunit o ... | 1999 | 10535927 |
| histidine-41 of the cytochrome b5 domain of the borage delta6 fatty acid desaturase is essential for enzyme activity. | unlike most other plant microsomal desaturases, the delta6-fatty acid desaturase from borage (borago officinalis) contains an n-terminal extension that shows homology to the small hemoprotein cytochrome (cyt) b5. to determine if this domain serves as a functional electron donor for the delta6-fatty acid desaturase, mutagenesis and functional analysis by expression in transgenic arabidopsis was carried out. although expression of the wild-type borage delta6-fatty acid desaturase resulted in the s ... | 1999 | 10517856 |
| phloem transport of d,l-glufosinate and acetyl-l-glufosinate in glufosinate-resistant and -susceptible brassica napus | phloem transport of d,l-[(14)c]glufosinate, d-[(14)c]glufosinate, and acetyl-l-[(14)c]glufosinate was examined in the susceptible brassica napus cv excel and a glufosinate-resistant genotype (hcn27) derived by transformation of cv excel with the phosphinothricin-n-acetyltransferase (pat) gene. considerably more (14)c was exported from an expanded leaf in hcn27 than in cv excel following application of d,l-[(14)c]glufosinate (25% versus 6.3% of applied, respectively, 72 h after treatment). the in ... | 1999 | 10517854 |
| arabidopsis alcohol dehydrogenase expression in both shoots and roots is conditioned by root growth environment. | it is widely accepted that the arabidopsis adh (alcohol dehydrogenase) gene is constitutively expressed at low levels in the roots of young plants grown on agar media, and that the expression level is greatly induced by anoxic or hypoxic stresses. we questioned whether the agar medium itself created an anaerobic environment for the roots upon their growing into the gel. beta-glucuronidase (gus) expression driven by the adh promoter was examined by growing transgenic arabidopsis plants in differe ... | 1999 | 10517834 |
| biosynthesis and immunolocalization of lewis a-containing n-glycans in the plant cell. | we recently demonstrated the presence of a new asparagine-linked complex glycan on plant glycoproteins that harbors the lewis a (lea), or galbeta(1-3)[fucalpha(1-4)]glcnac, epitope, which in mammalian cells plays an important role in cell-to-cell recognition. here we show that the monoclonal antibody jim 84, which is widely used as a golgi marker in light and electron microscopy of plant cells, is specific for the lea antigen. this antigen is present on glycoproteins of a number of flowering and ... | 1999 | 10517824 |
| comparison of proteins involved in pilus synthesis and mating pair stabilization from the related plasmids f and r100-1: insights into the mechanism of conjugation. | f and r100-1 are closely related, derepressed, conjugative plasmids from the incfi and incfii incompatibility groups, respectively. heteroduplex mapping and genetic analyses have revealed that the transfer regions are extremely similar between the two plasmids. plasmid specificity can occur at the level of relaxosome formation, regulation, and surface exclusion between the two transfer systems. there are also differences in pilus serology, pilus-specific phage sensitivity, and requirements for o ... | 1999 | 10464182 |
| antisense repression of hexokinase 1 leads to an overaccumulation of starch in leaves of transgenic potato plants but not to significant changes in tuber carbohydrate metabolism. | potato (solanum tuberosum l.) plants transformed with sense and antisense constructs of a cdna encoding the potato hexokinase 1 (sthk1) exhibited altered enzyme activities and expression of sthk1 mrna. measurements of the maximum catalytic activity of hexokinase revealed a 22-fold variation in leaves (from 22% of the wild-type activity in antisense transformants to 485% activity in sense transformants) and a 7-fold variation in developing tubers (from 32% of the wild-type activity in antisense t ... | 1999 | 10482667 |
| rare germinal unequal crossing-over leading to recombinant gene formation and gene duplication in arabidopsis thaliana. | small, multigene families organized in a tandem array can facilitate the rapid evolution of the gene cluster by a process of meiotic unequal crossing-over. to study this process in a multicellular organism, we created a synthetic rbcsb gene cluster in arabidopsis thaliana and used this to measure directly the frequency of meiotic, intergenic unequal crossing-over between sister chromatids. the synthetic rbcsb gene cluster was composed of a silent deltarbcs1b::luc chimeric gene fusion, lacking al ... | 1999 | 10468603 |
| the sporocyteless gene of arabidopsis is required for initiation of sporogenesis and encodes a novel nuclear protein. | the formation of haploid spores marks the initiation of the gametophytic phase of the life cycle of all vascular plants ranging from ferns to angiosperms. in angiosperms, this process is initiated by the differentiation of a subset of floral cells into sporocytes, which then undergo meiotic divisions to form microspores and megaspores. currently, there is little information available regarding the genes and proteins that regulate this key step in plant reproduction. we report here the identifica ... | 1999 | 10465788 |
| the far1 locus encodes a novel nuclear protein specific to phytochrome a signaling. | the phytochrome family of photoreceptors has a well-defined role in regulating gene expression in response to informational light signals. little is known, however, of the early steps of phytochrome signal transduction. here we describe a new arabidopsis mutant, far1 (far-red-impaired response), which has reduced responsiveness to continuous far-red light, but responds normally to other light wavelengths. this phenotype implies a specific requirement for far1 in phya signal transduction. the far ... | 1999 | 10444599 |
| accumulation of soybean glycinin and its assembly with the glutelins in rice | saline-soluble glycinins and insoluble glutelins are the major storage proteins in soybean (glycine max) and rice (oryza sativa), respectively. in spite of their differences in solubility properties, both proteins are members of the 11s globulin gene family based on their similarities in primary sequences and processing of the coded protein. wild-type and methionine-modified glycinin coding sequences were expressed in transgenic rice plants under the control of the rice glutelin glub-1 promoter. ... | 1999 | 10444090 |
| nuclear import of plasmid dna in digitonin-permeabilized cells requires both cytoplasmic factors and specific dna sequences. | although much is known about the mechanisms of signal-mediated protein and rna nuclear import and export, little is understood concerning the nuclear import of plasmid dna. plasmids between 4.2 and 14.4 kilobases were specifically labeled using a fluorescein-conjugated peptide nucleic acid clamp. the resulting substrates were capable of gene expression and nuclear localization in microinjected cells in the absence of cell division. to elucidate the requirements for plasmid nuclear import, a digi ... | 1999 | 10419528 |
| regions of the pea lhcb1*4 promoter necessary for blue-light regulation in transgenic arabidopsis. | pea (pisum sativum) and arabidopsis contain similar, if not identical, blue-light (bl)-responsive systems that alter expression of specific members of the lhcb (light-harvesting chlorophyll-binding) gene family. in both plants a single, short pulse of low-fluence bl (threshold = 10(-1) micromol m-2) causes an increase in the rate of transcription from specific members of the lhcb gene family in etiolated seedlings. constructs of the bl-regulated pea lhcb1*4 promoter (pslhcb1*4) were created, whi ... | 1999 | 10398709 |
| eaf1 regulates vegetative-phase change and flowering time in arabidopsis. | we have identified a new locus that regulates vegetative phase change and flowering time in arabidopsis. an early-flowering mutant, eaf1 (early flowering 1) was isolated and characterized. eaf1 plants flowered earlier than the wild type under either short-day or long-day conditions, and showed a reduction in the juvenile and adult vegetative phases. when grown under short-day conditions, eaf1 plants were slightly pale green and had elongated petioles, phenotypes that are observed in mutants alte ... | 1999 | 10398702 |
| decreased cell wall digestibility in canola transformed with chimeric tyrosine decarboxylase genes from opium poppy | tyrosine decarboxylase (tydc) is a common plant enzyme involved in the biosynthesis of numerous secondary metabolites, including hydroxycinnamic acid amides. although a definite function has not yet been determined, amides have been proposed to form a physical barrier against pathogens because they are usually found as integral cell wall components. canola (brassica napus) was independently transformed with chimeric genes (35s::tydc1 and 35s::tydc2) under the transcriptional control of the cauli ... | 1999 | 10398700 |
| phytoremediation of methylmercury pollution: merb expression in arabidopsis thaliana confers resistance to organomercurials. | methylmercury is an environmental toxicant that biomagnifies and causes severe neurological degeneration in animals. it is produced by bacteria in soils and sediments that have been contaminated with mercury. to explore the potential of plants to extract and detoxify this chemical, we engineered a model plant, arabidopsis thaliana, to express a modified bacterial gene, merbpe, encoding organomercurial lyase (merb) under control of a plant promoter. merb catalyzes the protonolysis of the carbon-- ... | 1999 | 10359794 |
| white anther: a petunia mutant that abolishes pollen flavonol accumulation, induces male sterility, and is complemented by a chalcone synthase transgene | a mutation in an inbred line of petunia (petunia hybrida) produces a reduction in the deep-purple corolla pigmentation and changes the anther color from yellow to white. in addition, the mutant, designated white anther (wha), is functionally male sterile. the inability of pollen from wha plants to germinate in vitro provides a physiological basis for the lack of seed set observed in self-crosses of the mutant. biochemical complementation with nanomolar amounts of kaempferol, a flavonol aglycone, ... | 1999 | 10364414 |
| transgenic overexpression of the transcription factor alfin1 enhances expression of the endogenous msprp2 gene in alfalfa and improves salinity tolerance of the plants | alfin1 cdna encodes a putative transcription factor associated with nacl tolerance in alfalfa (medicago sativa l.). the recombinant protein binds dna in a sequence-specific manner, including promoter fragments of the nacl-inducible gene msprp2. alfin1 function was tested in transgenic alfalfa under the control of the 35s promoter in the sense and antisense orientations with the endogenous msprp2 as a reporter gene. calli overexpressing alfin1 were more resistant to growth inhibition by 171 mm na ... | 1999 | 10364398 |
| plastid sedimentation kinetics in roots of wild-type and starch-deficient mutants of arabidopsis. | sedimentation and movement of plastids in columella cells of the root cap were measured in seedlings of wild-type, a reduced starch mutant, and a starchless mutant of arabidopsis. to assay for sedimentation, we used both linear measurements and the change of angle from the cell center as indices in vertical and reoriented plants with the aid of computer-assisted image analysis. seedlings were fixed at short periods after reorientation, and plastid sedimentation correlated with starch content in ... | 1999 | 10318696 |
| differential expression of two novel members of the tomato ethylene-receptor family. | the phytohormone ethylene regulates many aspects of plant growth, development, and environmental responses. much of the developmental regulation of ethylene responses in tomato (lycopersicon esculentum) occurs at the level of hormone sensitivity. in an effort to understand the regulation of ethylene responses, we isolated and characterized tomato genes with sequence similarity to the arabidopsis etr1 (ethylene response 1) ethylene receptor. previously, we isolated three genes that exhibit high s ... | 1999 | 10318694 |
| overexpression of arabidopsis phytochrome b inhibits phytochrome a function in the presence of sucrose. | overexpression of phytochrome b (phyb) in arabidopsis has previously been demonstrated to result in dominant negative interference of phytochrome a (phya)-mediated hypocotyl growth inhibition in far-red (fr) light. this phenomenon has been examined further in this study and has been found to be dependent on the fr fluence rate and on the availability of metabolizable sugars in the growth medium. poorly metabolized sugars capable of activating the putative hexokinase sensory function were not eff ... | 1999 | 10198109 |
| protective function of chloroplast 2-cysteine peroxiredoxin in photosynthesis. evidence from transgenic arabidopsis. | 2-cysteine peroxiredoxins (2-cps) constitute a ubiquitous group of peroxidases that reduce cell-toxic alkyl hydroperoxides to their corresponding alcohols. recently, we cloned 2-cp cdnas from plants and characterized them as chloroplast proteins. to elucidate the physiological function of the 2-cp in plant metabolism, we generated antisense mutants in arabidopsis. in the mutant lines a 2-cp deficiency developed during early leaf and plant development and eventually the protein accumulated to wil ... | 1999 | 10198100 |
| extragenic suppressors of the arabidopsis gai mutation alter the dose-response relationship of diverse gibberellin responses. | active gibberellins (gas) are endogenous factors that regulate plant growth and development in a dose-dependent fashion. mutant plants that are ga deficient, or exhibit reduced ga responses, display a characteristic dwarf phenotype. extragenic suppressor analysis has resulted in the isolation of arabidopsis mutations, which partially suppress the dwarf phenotype conferred by ga deficiency and reduced ga-response mutations. here we describe detailed studies of the effects of two of these suppress ... | 1999 | 10198078 |
| identification of a calmodulin-regulated ca2+-atpase in the endoplasmic reticulum. | a unique subfamily of calmodulin-dependent ca2+-atpases was recently identified in plants. in contrast to the most closely related pumps in animals, plasma membrane-type ca2+-atpases, members of this new subfamily are distinguished by a calmodulin-regulated autoinhibitor located at the n-terminal instead of a c-terminal end. in addition, at least some isoforms appear to reside in non-plasma membrane locations. to begin delineating their functions, we investigated the subcellular localization of ... | 1999 | 10198075 |
| antisense expression of the ck2 alpha-subunit gene in arabidopsis. effects on light-regulated gene expression and plant growth. | the protein kinase ck2 (formerly casein kinase ii) is thought to be involved in light-regulated gene expression in plants because of its ability to phosphorylate transcription factors that bind to the promoter regions of light-regulated genes in vitro. to address this possibility in vivo and to learn more about the potential physiological roles of ck2 in plants, we transformed arabidopsis with an antisense construct of the ck2 alpha-subunit gene and investigated both morphological and molecular ... | 1999 | 10069836 |
| winter survival of transgenic alfalfa overexpressing superoxide dismutase | to test the hypothesis that enhanced tolerance of oxidative stress would improve winter survival, two clones of alfalfa (medicago sativa) were transformed with a mn-superoxide dismutase (mn-sod) targeted to the mitochondria or to the chloroplast. although mn-sod activity increased in most primary transgenic plants, both cytosolic and chloroplastic forms of cu/zn-sod had lower activity in the chloroplast sod transgenic plants than in the nontransgenic plants. in a field trial at elora, ontario, c ... | 1999 | 10069823 |
| overexpression of a novel arabidopsis gene related to putative zinc-transporter genes from animals can lead to enhanced zinc resistance and accumulation. | we describe the isolation of an arabidopsis gene that is closely related to the animal znt genes (zn transporter). the protein encoded by the zat (zn transporter of arabidopsis thaliana) gene has 398 amino acid residues and is predicted to have six membrane-spanning domains. to obtain evidence for the postulated function of the arabidopsis gene, transgenic plants with the zat coding sequence under control of the cauliflower mosaic virus 35s promoter were analyzed. plants obtained with zat in the ... | 1999 | 10069843 |
| the interaction between cold and light controls the expression of the cold-regulated barley gene cor14b and the accumulation of the corresponding protein. | we report the expression of the barley (hordeum vulgare l.) cor (cold-regulated) gene cor14b (formerly pt59) and the accumulation of its chloroplast-localized protein product. a polyclonal antibody raised against the cor14b-encoded protein detected two chloroplast cor proteins: cor14a and cor14b. n-terminal sequencing of cor14a and expression of cor14b in arabidopsis plants showed that cor14a is not encoded by the cor14b sequence, but it shared homology with the wheat (triticum aestivum l.) wcs1 ... | 1999 | 9952464 |
| mutations affecting induction of glycolytic and fermentative genes during germination and environmental stresses in arabidopsis. | expression of the alcohol dehydrogenase gene (adh) of arabidopsis is known to be induced by environmental stresses and regulated developmentally. we used a negative-selection approach to isolate mutants that were defective in regulating the expression of the adh gene during seed germination; we then characterized three recessive mutants, aar1-1, aar1-2, and aar2-1, which belong to two complementation groups. in addition to their defects during seed germination, mutations in the aar1 and aar2 gen ... | 1999 | 9952456 |
| flavonoids promote haustoria formation in the root parasite triphysaria versicolor | parasitic plants in the scrophulariaceae develop infective root structures called haustoria in response to chemical signals released from host-plant roots. this study used a simple in vitro assay to characterize natural and synthetic molecules that induce haustoria in the facultative parasite triphysaria versicolor. several phenolic acids, flavonoids, and the quinone 2,6-dimethoxy-p-benzoquinone induced haustoria in t. versicolor root tips within hours after treatment. the concentration at which ... | 1999 | 9952454 |
| genes controlling fertilization-independent seed development in arabidopsis thaliana. | we have cloned two genes, fis1 and fis2, that control both fertilization independent seed development and postpollination embryo development in arabidopsis. these genes confer female gametophytic phenotypes. fis2 encodes a protein with a c2h2 zinc-finger motif and three putative nuclear localization signals, indicating that it is likely to be a transcription factor. fis1 encodes a protein with homology to the drosophila polycomb group gene enhancer-of-zeste and is identical to the recently descr ... | 1999 | 9874812 |
| regulation of s-like ribonuclease levels in arabidopsis. antisense inhibition of rns1 or rns2 elevates anthocyanin accumulation. | the s-like ribonucleases (rnases) rns1 and rns2 of arabidopsis are members of the widespread t2 ribonuclease family, whose members also include the s-rnases, involved in gametophytic self-incompatibility in plants. both rns1 and rns2 mrnas have been shown previously to be induced by inorganic phosphate (pi) starvation. in our study we examined this regulation at the protein level and determined the effects of diminishing rns1 and rns2 expression using antisense techniques. the pi-starvation cont ... | 1999 | 9880376 |
| arginase is inoperative in developing soybean embryos. | arginase (ec 3.5.3.1) transcript level and activity were measured in soybean (glycine max l.) embryos from the reserve deposition stage to postgermination. using a cdna probe for a small soybean arginase gene family, no transcript was detected in developing embryos. however, arginase transcripts increased sharply on germination, reaching a maximum at 3 to 5 d after germination. there was low but measurable in vitro arginase specific activity in developing embryos (less than 6% of seedling maximu ... | 1999 | 9880372 |
| interaction of osmotic stress, temperature, and abscisic acid in the regulation of gene expression in arabidopsis. | the impact of simultaneous environmental stresses on plants and how they respond to combined stresses compared with single stresses is largely unclear. by using a transgene (rd29a-luc) consisting of the firefly luciferase coding sequence (luc) driven by the stress-responsive rd29a promoter, we investigated the interactive effects of temperature, osmotic stress, and the phytohormone abscisic acid (aba) in the regulation of gene expression in arabidopsis seedlings. results indicated that both posi ... | 1999 | 9880362 |
| overexpression of atp sulfurylase in indian mustard leads to increased selenate uptake, reduction, and tolerance | in earlier studies, the assimilation of selenate by plants appeared to be limited by its reduction, a step that is thought to be mediated by atp sulfurylase. here, the arabidopsis aps1 gene, encoding a plastidic atp sulfurylase, was constitutively overexpressed in indian mustard (brassica juncea). compared with that in untransformed plants, the atp sulfurylase activity was 2- to 2.5-fold higher in shoots and roots of transgenic seedlings, and 1. 5- to 2-fold higher in shoots but not roots of sel ... | 1999 | 9880353 |
| metabolic engineering of plant alkaloid biosynthesis. | plant alkaloids, one of the largest groups of natural products, provide many pharmacologically active compounds. several genes in the biosynthetic pathways for scopolamine, nicotine, and berberine have been cloned, making the metabolic engineering of these alkaloids possible. expression of two branching-point enzymes was engineered: putrescine n-methyltransferase (pmt) in transgenic plants of atropa belladonna and nicotiana sylvestris and (s)-scoulerine 9-o-methyltransferase (smt) in cultured ce ... | 2000 | 11134522 |
| metabolic engineering of plant alkaloid biosynthesis. | plant alkaloids, one of the largest groups of natural products, provide many pharmacologically active compounds. several genes in the biosynthetic pathways for scopolamine, nicotine, and berberine have been cloned, making the metabolic engineering of these alkaloids possible. expression of two branching-point enzymes was engineered: putrescine n-methyltransferase (pmt) in transgenic plants of atropa belladonna and nicotiana sylvestris and (s)-scoulerine 9-o-methyltransferase (smt) in cultured ce ... | 2000 | 11134522 |
| arabidopsis nac1 transduces auxin signal downstream of tir1 to promote lateral root development. | auxin plays a key role in lateral root formation, but the signaling pathway for this process is poorly understood. we show here that nac1, a new member of the nac family, is induced by auxin and mediates auxin signaling to promote lateral root development. nac1 is a transcription activator consisting of an n-terminal conserved nac-domain that binds to dna and a c-terminal activation domain. this factor activates the expression of two downstream auxin-responsive genes, dbp and air3. transgenic pl ... | 2000 | 11114891 |
| a novel two-component hybrid molecule regulates vascular morphogenesis of the arabidopsis root. | the developmental ontogeny of the vascular system (consisting of xylem, phloem and [pro]cambium) is poorly understood despite its central role in plant physiology. we show that in the arabidopsis root meristem, xylem cell lineages are specified early, whereas phloem and procambium are established through a set of asymmetric cell divisions. these divisions require the wooden leg (wol) gene. the wol gene encodes a novel two-component signal transducer with an unusual tandem arrangement of two rece ... | 2000 | 11114883 |
| multiple cellulose synthase catalytic subunits are required for cellulose synthesis in arabidopsis. | the irregular xylem 1 (irx1) mutant of arabidopsis has a severe deficiency in the deposition of cellulose in secondary cell walls, which results in collapsed xylem cells. this mutation has been mapped to a 140-kb region of chromosome 4. a cellulose synthase catalytic subunit was found to be located in this region, and genomic clones containing this gene complemented the irx1 mutation. irx1 shows homology to a previously described cellulose synthase (irx3). analysis of the irx1 and irx3 mutant ph ... | 2000 | 11148295 |
| cloning of the arabidopsis rsf1 gene by using a mapping strategy based on high-density dna arrays and denaturing high-performance liquid chromatography. | mapping genes by chromosome walking is a widely used technique applicable to cloning virtually any gene that is identifiable by mutagenesis. we isolated the gene responsible for the recessive mutation rsf1 (for reduced sensitivity to far-red light) in the arabidopsis columbia accession by using classical genetic analysis and two recently developed technologies: genotyping high-density oligonucleotide dna array and denaturing high-performance liquid chromatography (dhplc). the arabidopsis at412 g ... | 2000 | 11148292 |
| procuste1 encodes a cellulose synthase required for normal cell elongation specifically in roots and dark-grown hypocotyls of arabidopsis. | mutants at the procuste1 (prc1) locus show decreased cell elongation, specifically in roots and dark-grown hypocotyls. cell elongation defects are correlated with a cellulose deficiency and the presence of gapped walls. map-based cloning of prc1 reveals that it encodes a member (cesa6) of the cellulose synthase catalytic subunit family, of which at least nine other members exist in arabidopsis. mutations in another family member, rsw1 (cesa1), cause similar cell wall defects in all cell types, i ... | 2000 | 11148287 |