Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| redirection of flavonoid biosynthesis through the down-regulation of an anthocyanidin glucosyltransferase in ripening strawberry fruit. | strawberry (fragaria x ananassa) fruit contains several anthocyanins that give the ripe fruits their attractive red color. the enzyme that catalyzes the formation of the first stable intermediate in the anthocyanin pathway is anthocyanidin-3-o-glucosyltransferase. a putative glycosyltransferase sequence (fagt1) was cloned from a strawberry fruit cdna library and the recombinant fagt1 transferred udp-glucose to anthocyanidins and, to a lesser extent, flavonols, generating the respective 3-o-gluco ... | 2008 | 18258692 |
| structural insight into the reaction mechanism and evolution of cytokinin biosynthesis. | the phytohormone cytokinin regulates plant growth and development. this hormone is also synthesized by some phytopathogenic bacteria, such as agrobacterium tumefaciens, and is as a key factor in the formation of plant tumors. the rate-limiting step of cytokinin biosynthesis is catalyzed by adenosine phosphate-isopentenyltransferase (ipt). agrobacterium ipt has a unique substrate specificity that enables it to increase trans-zeatin production by recruiting a metabolic intermediate of the host pla ... | 2008 | 18258747 |
| the growing outer epidermal wall: design and physiological role of a composite structure. | the cells of growing plant organs secrete an extracellular fibrous composite (the primary wall) that allows the turgid protoplasts to expand irreversibly via wall-yielding events, which are regulated by processes within the cytoplasm. the role of the epidermis in the control of stem elongation is described with special reference to the outer epidermal wall (oew), which forms a 'tensile skin'. | 2008 | 18258808 |
| secretome analysis uncovers an hcp-family protein secreted via a type vi secretion system in agrobacterium tumefaciens. | agrobacterium tumefaciens is a plant-pathogenic bacterium capable of secreting several virulence factors into extracellular space or the host cell. in this study, we used shotgun proteomics analysis to investigate the secretome of a. tumefaciens, which resulted in identification of 12 proteins, including 1 known secretory protein (virb1*) and 11 potential secretory proteins. interestingly, one unknown protein, which we designated hemolysin-coregulated protein (hcp), is a predicted soluble protei ... | 2008 | 18263727 |
| the hopz family of pseudomonas syringae type iii effectors require myristoylation for virulence and avirulence functions in arabidopsis thaliana. | pseudomonas syringae utilizes the type iii secretion system to translocate effector proteins into plant cells, where they can contribute to the pathogen's ability to infect and cause disease. recognition of these effectors by resistance proteins induces defense responses that typically include a programmed cell death reaction called the hypersensitive response. the yopj/hopz family of type iii effector proteins is a common family of effector proteins found in animal- and plant-pathogenic bacteri ... | 2008 | 18263728 |
| map65-3 microtubule-associated protein is essential for nematode-induced giant cell ontogenesis in arabidopsis. | the infection of plants by obligate parasitic nematodes constitutes an interesting model for investigating plant cytoskeleton functions. root knot nematodes have evolved the ability to manipulate host functions to their own advantage by redifferentiating root cells into multinucleate and hypertrophied feeding cells. these giant cells result from repeated rounds of karyokinesis without cell division. detailed functional analyses demonstrated that arabidopsis thaliana microtubule-associated protei ... | 2008 | 18263774 |
| a novel wrky transcription factor is required for induction of pr-1a gene expression by salicylic acid and bacterial elicitors. | pr-1a is a salicylic acid-inducible defense gene of tobacco (nicotiana tabacum). one-hybrid screens identified a novel tobacco wrky transcription factor (ntwrky12) with specific binding sites in the pr-1a promoter at positions -564 (box wk(1)) and -859 (box wk(2)). ntwrky12 belongs to the class of transcription factors in which the wrky sequence is followed by a gkk rather than a gqk sequence. the binding sequence of ntwrky12 (wk box ttttccac) deviated significantly from the consensus sequence ( ... | 2008 | 18263781 |
| osphr2 is involved in phosphate-starvation signaling and excessive phosphate accumulation in shoots of plants. | previous research has demonstrated that atphr1 plays a central role in phosphate (pi)-starvation signaling in arabidopsis thaliana. in this work, two osphr genes from rice (oryza sativa) were isolated and designated as osphr1 and osphr2 based on amino acid sequence homology to atphr1. their functions in pi signaling in rice were investigated using transgenic plants. our results showed that both osphr1 and osphr2 are involved in pi-starvation signaling pathway by regulation of the expression of p ... | 2008 | 18263782 |
| senescence-induced ectopic expression of the a. tumefaciens ipt gene in wheat delays leaf senescence, increases cytokinin content, nitrate influx, and nitrate reductase activity, but does not affect grain yield. | the manipulation of cytokinin levels by senescence-regulated expression of the agrobacterium tumefaciens ipt gene through its control by the arabidopsis sag12 (senescence-associated gene 12) promoter is an efficient tool for the prolongation of leaf photosynthetic activity which potentially can affect plant productivity. in the present study, the efficiency of this approach was tested on wheat (triticum aestivum l.)-a monocarpic plant characterized by a fast switch from vegetative to reproductiv ... | 2008 | 18267946 |
| tobacco rattle virus 16-kilodalton protein encodes a suppressor of rna silencing that allows transient viral entry in meristems. | rna silencing is a host defense mechanism that limits the accumulation and spread of viruses in infected plants. correspondingly, plant viruses encode suppressors of silencing. in the positive-strand rna virus tobacco rattle virus (trv), the suppressor of silencing is a 16-kda (16k) protein encoded by rna1. the suppressor action of the 16k protein is transient and weaker than that of the p19 suppressor, encoded by tomato bushy stunt virus. mutant trv that does not produce its suppressor, unlike ... | 2008 | 18272576 |
| trar auto-inducer enhances protein backbone fluctuations in dna binding domain. | the bacterium agrobacterium tumefaciens mediates quorum sensing via trar, a n-3-oxo-octanoyl-l-homoserine lactone (oohl) signaling transcription factor. trar consists of an n-terminal per-arnt-sim domain (pas-domain) containing oohl and a c-terminal helix-turn-helix motif (htf-motif) binding dna, thus comprising a complete signaling pathway. using molecular dynamics, we investigate the influence of oohl on the dynamics of the protein. the oohl binding pocket is in contact with water, leading to ... | 2008 | 18275856 |
| isolation and characterization of an autoinducer synthase from acinetobacter baumannii. | the opportunistic human pathogen acinetobacter baumannii strain m2 was found to produce distinct acyl-homoserine lactone (ahl) signals based on the use of an agrobacterium tumefaciens trag-lacz biosensor. an a. baumannii gene, designated abai, was cloned and directed ahl production in recombinant escherichia coli. the abai protein was similar to members of the luxi family of autoinducer synthases and was predicted to be the only autoinducer synthase encoded by a. baumannii. the primary ahl signa ... | 2008 | 18281398 |
| mechanistic flexibility as a conserved theme across 3 billion years of nonhomologous dna end-joining. | 2008 | 18281457 | |
| the pathways and outcomes of mycobacterial nhej depend on the structure of the broken dna ends. | mycobacteria can repair dna double-strand breaks (dsbs) via a nonhomologous end-joining (nhej) system that includes a dedicated dna ligase (ligd) and the dna end-binding protein ku. here we exploit an improved plasmid-based nhej assay and a collection of mycobacterium smegmatis strains bearing deletions or mutations in ku or the dna ligases to interrogate the contributions of ligd's three catalytic activities (polymerase, ligase, and 3' phosphoesterase) and structural domains (pol, lig, and pe) ... | 2008 | 18281464 |
| the arabidopsis phosphatidylinositol phosphate 5-kinase pip5k3 is a key regulator of root hair tip growth. | phosphatidylinositol 4,5-bisphosphate [ptdins(4,5)p2] functions as a site-specific signal on membranes to promote cytoskeletal reorganization and membrane trafficking. localization of ptdins(4,5)p2 to apices of growing root hairs and pollen tubes suggests that it plays an important role in tip growth. however, its regulation and mode of action remain unclear. we found that arabidopsis thaliana pip5k3 (for phosphatidylinositol phosphate 5-kinase 3) encodes a phosphatidylinositol 4-phosphate 5-kin ... | 2008 | 18281506 |
| root hair defective4 encodes a phosphatidylinositol-4-phosphate phosphatase required for proper root hair development in arabidopsis thaliana. | polarized expansion of root hair cells in arabidopsis thaliana is improperly controlled in root hair-defective rhd4-1 mutant plants, resulting in root hairs that are shorter and randomly form bulges along their length. using time-lapse fluorescence microscopy in rhd4-1 root hairs, we analyzed membrane dynamics after labeling with raba4b, a marker for polarized membrane trafficking in root hairs. this revealed stochastic loss and recovery of the raba4b compartment in the tips of growing root hair ... | 2008 | 18281508 |
| embryonic flower1 participates in polycomb group-mediated ag gene silencing in arabidopsis. | polycomb group (pcg)-mediated gene silencing is a common developmental strategy used to maintain stably inherited repression of target genes and involves different protein complexes known as polycomb-repressive complexes (prcs). in animals, the two best-characterized pcg complexes are prc1 and prc2. in this report, we demonstrate that the plant-specific protein embryonic flower1 (emf1) functions in maintaining the repression of the flower homeotic gene agamous (ag) during vegetative development ... | 2008 | 18281509 |
| isolation of a strong arabidopsis guard cell promoter and its potential as a research tool. | abstract: | 2008 | 18284694 |
| allelic mutant series reveal distinct functions for arabidopsis cycloartenol synthase 1 in cell viability and plastid biogenesis. | sterols have multiple functions in all eukaryotes. in plants, sterol biosynthesis is initiated by the enzymatic conversion of 2,3-oxidosqualene to cycloartenol. this reaction is catalyzed by cycloartenol synthase 1 (cas1), which belongs to a family of 13 2,3-oxidosqualene cyclases in arabidopsis thaliana. to understand the full scope of sterol biological functions in plants, we characterized allelic series of cas1 mutations. plants carrying the weak mutant allele cas1-1 were viable but developed ... | 2008 | 18287026 |
| control of compound leaf development by floricaula/leafy ortholog single leaflet1 in medicago truncatula. | molecular genetic studies suggest that floricaula (flo)/leafy (lfy) orthologs function to control compound leaf development in some legume species. however, loss-of-function mutations in the flo/lfy orthologs result in reduction of leaf complexity to different degrees in pisum sativum and lotus japonicus. to further understand the role of flo/lfy orthologs in compound leaf development in legumes, we studied compound leaf developmental processes and characterized a leaf development mutant, single ... | 2008 | 18287485 |
| examining the specific contributions of individual arabidopsis metallothioneins to copper distribution and metal tolerance. | metallothioneins (mts) are small cysteine-rich proteins found in various eukaryotes. plant mts are classified into four types based on the arrangement of cysteine residues. to determine whether all four types of plant mts function as metal chelators, six arabidopsis (arabidopsis thaliana) mts (mt1a, mt2a, mt2b, mt3, mt4a, and mt4b) were expressed in the copper (cu)- and zinc (zn)-sensitive yeast mutants, deltacup1 and deltazrc1 deltacot1, respectively. all four types of arabidopsis mts provided ... | 2008 | 18287486 |
| recent advances in medicago truncatula genomics. | legume rotation has allowed a consistent increase in crop yield and consequently in human population since the antiquity. legumes will also be instrumental in our ability to maintain the sustainability of our agriculture while facing the challenges of increasing food and biofuel demand. medicago truncatula and lotus japonicus have emerged during the last decade as two major model systems for legume biology. initially developed to dissect plant-microbe symbiotic interactions and especially legume ... | 2008 | 18288239 |
| recent advances in medicago truncatula genomics. | legume rotation has allowed a consistent increase in crop yield and consequently in human population since the antiquity. legumes will also be instrumental in our ability to maintain the sustainability of our agriculture while facing the challenges of increasing food and biofuel demand. medicago truncatula and lotus japonicus have emerged during the last decade as two major model systems for legume biology. initially developed to dissect plant-microbe symbiotic interactions and especially legume ... | 2008 | 18288239 |
| rhizobium radiobacter as an opportunistic pathogen in central venous catheter-associated bloodstream infection: case report and review. | rhizobium radiobacter is an uncommon opportunistic pathogen present in soil. it has been particularly associated with indwelling intravascular devices in immunocompromised patients. in this report, we summarise the case of a patient with multiple myeloma who developed r. radiobacter bacteraemia during autologous stem cell leucopheresis. retrospective investigation revealed exposure to soil after central venous catheter placement for chemotherapy and leucopheresis access. this is the first report ... | 2008 | 18289729 |
| the highly repetitive region of the helicobacter pylori cagy protein comprises tandem arrays of an alpha-helical repeat module. | the cag-pathogenicity-island-encoded type iv secretion system of helicobacter pylori functions to translocate the effector protein caga directly through the plasma membrane of gastric epithelial cells. similar to other secretion systems, the cag type iv secretion system elaborates a surface filament structure, which is unusually sheathed by the large cag-pathogenicity-island-encoded protein cagy. cagy is distinguished by unusual amino acid composition and extensive repetitive sequence organised ... | 2008 | 18295231 |
| identification of a novel adenine nucleotide transporter in the endoplasmic reticulum of arabidopsis. | many metabolic reactions in the endoplasmic reticulum (er) require high levels of energy in the form of atp, which is important for cell viability. here, we report on an adenine nucleotide transporter residing in the er membranes of arabidopsis thaliana (er-ant1). functional integration of er-ant1 in the cytoplasmic membrane of intact escherichia coli cells reveals a high specificity for an atp/adp antiport. immunodetection in transgenic er-ant1-c-myc-tag arabidopsis plants and immunogold labeli ... | 2008 | 18296626 |
| cop1-mediated ubiquitination of constans is implicated in cryptochrome regulation of flowering in arabidopsis. | in arabidopsis thaliana, the blue light photoreceptor cryptochromes (cry) act to promote photomorphogenic development and the transition from vegetative to floral development in long days (lds). we previously proposed that one of the mechanisms by which cry regulates light responses is via its physical interaction with cop1, a ring motif-containing e3 ligase. under lds, the transcription of flowering locus t (ft) is activated by constans (co) in leaf, and the ft protein moves to the shoot apex t ... | 2008 | 18296627 |
| origin and evolution of gala-lrr, a new member of the cc-lrr subfamily: from plants to bacteria? | the phytopathogenic bacterium ralstonia solanacearum encodes type iii effectors, called gala proteins, which contain f-box and lrr domains. the gala lrrs do not perfectly fit any of the previously described lrr subfamilies. by applying protein sequence analysis and structural prediction, we clarify this ambiguous case of lrr classification and assign gala-lrrs to cc-lrr subfamily. we demonstrate that side-by-side packing of lrrs in the 3d structures may control the limits of repeat variability w ... | 2008 | 18301771 |
| agrobacterium tumefaciens-mediated transformation of taro (colocasia esculenta (l.) schott) with a rice chitinase gene for improved tolerance to a fungal pathogen sclerotium rolfsii. | taro (colocasia esculenta) is one of the most important crops in the pacific islands, however, taro yields have been declining in hawaii over the past 30 years partly due to diseases caused by oomycete and fungal pathogens. in this study, an efficient agrobacterium tumefaciens-mediated transformation method for taro is first reported. in total, approximately 200 pieces (8 g) of embryogenic calluses were infected with the super-virulent a. tumefaciens strain eha105 harboring the plant transformat ... | 2008 | 18301900 |
| vire2: a unique ssdna-compacting molecular machine. | the translocation of single-stranded dna (ssdna) across membranes of two cells is a fundamental biological process occurring in both bacterial conjugation and agrobacterium pathogenesis. whereas bacterial conjugation spreads antibiotic resistance, agrobacterium facilitates efficient interkingdom transfer of ssdna from its cytoplasm to the host plant cell nucleus. these processes rely on the type iv secretion system (t4ss), an active multiprotein channel spanning the bacterial inner and outer mem ... | 2008 | 18303950 |
| metabolic and developmental adaptations of growing potato tubers in response to specific manipulations of the adenylate energy status. | heterotrophic carbon metabolism has been demonstrated to be limited by oxygen availability in a variety of plant tissues, which in turn inevitably affects the adenylate status. to study the effect of altering adenylate energy metabolism, without changing the oxygen supply, we expressed a plastidially targeted atp/adp hydrolyzing phosphatase (apyrase) in tubers of growing potato (solanum tuberosum) plants under the control of either inducible or constitutive promoters. inducible apyrase expressio ... | 2008 | 18305207 |
| 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 |
| 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 |
| rna-interference in rice against rice tungro bacilliform virus results in its decreased accumulation in inoculated rice plants. | rice tungro is a viral disease seriously affecting rice production in south and southeast asia. tungro is caused by the simultaneous infection in rice of rice tungro bacilliform virus (rtbv), a double-stranded dna virus and rice tungro spherical virus (rtsv), a single-stranded rna virus. to apply the concept of rna-interference (rnai) for the control of rtbv infection, transgenic rice plants expressing dna encoding orf iv of rtbv, both in sense as well as in anti-sense orientation, resulting in ... | 2008 | 18306054 |
| atmrp6/atabcc6, an atp-binding cassette transporter gene expressed during early steps of seedling development and up-regulated by cadmium in arabidopsis thaliana. | abc proteins constitute one of the largest families of transporters found in all living organisms. in arabidopsis thaliana, 120 genes encoding abc transporters have been identified. here, the characterization of one member of the mrp subclass, atmrp6, is described. | 2008 | 18307782 |
| agrobacterium-mediated transformation of the endophytic fungus acremonium implicatum associated with brachiaria grasses. | acremonium implicatum is a seed-transmitted endophytic fungus that forms symbiotic associations with the economically significant tropical forage grasses, brachiaria species. to take advantage of the endophyte's plant protective properties, we developed an efficient agrobacterium-mediated transformation system for acremonium implicatum, using green fluorescent protein (gfp) expression and vector psk1019 (trpc promoter) or pcambia1300 (camv35s promoter). we found that transformation efficiency do ... | 2008 | 18308527 |
| agrobacterium tumefaciens-mediated transformation in colletotrichum falcatum and c. acutatum. | agrobacterium tumefaciens-mediated transformation (atmt) is becoming an effective system as an insertional mutagenesis tool in filamentous fungi. we developed and optimized atmt for two colletotrichum species, c. falcatum and c. acutatum, which are the causal agents of sugarcane red rot and pepper anthracnose, respectively. a. tumefaciens strain sk1044, carrying a hygromycin phosphotransferase gene (hph) and a green fluorescent protein (gfp) gene, was used to transform the conidia of these two c ... | 2008 | 18309266 |
| biochemical and phylogenetic characterization of a novel diaminopimelate biosynthesis pathway in prokaryotes identifies a diverged form of ll-diaminopimelate aminotransferase. | a variant of the diaminopimelate (dap)-lysine biosynthesis pathway uses an ll-dap aminotransferase (dapl, ec 2.6.1.83) to catalyze the direct conversion of l-2,3,4,5-tetrahydrodipicolinate to ll-dap. comparative genomic analysis and experimental verification of dapl candidates revealed the existence of two diverged forms of dapl (dapl1 and dapl2). dapl orthologs were identified in eubacteria and archaea. in some species the corresponding dapl gene was found to lie in genomic contiguity with othe ... | 2008 | 18310350 |
| 1-aminocyclopropane-1-carboxylate deaminase enhances agrobacterium tumefaciens-mediated gene transfer into plant cells. | agrobacterium-mediated gene transfer is widely used for plant molecular genetics, and efficient techniques are required. recent studies show that ethylene inhibits the gene transfer. to suppress ethylene evolution, we introduced 1-aminocyclopropane-1-carboxylate (acc) deaminase into agrobacterium tumefaciens. the acc deaminase enhanced a. tumefaciens-mediated gene transfer into plants. | 2008 | 18310418 |
| polysaccharides cellulose, poly-beta-1,6-n-acetyl-d-glucosamine, and colanic acid are required for optimal binding of escherichia coli o157:h7 strains to alfalfa sprouts and k-12 strains to plastic but not for binding to epithelial cells. | when escherichia coli o157:h7 bacteria are added to alfalfa sprouts growing in water, the bacteria bind tightly to the sprouts. in contrast, laboratory k-12 strains of e. coli do not bind to sprouts under similar conditions. the roles of e. coli o157:h7 lipopolysaccharide (lps), capsular polysaccharide, and exopolysaccharides in binding to sprouts were examined. an lps mutant had no effect on the binding of the pathogenic strain. cellulose synthase mutants showed a significant reduction in bindi ... | 2008 | 18310435 |
| the vibrio cholerae mrp system: cation/proton antiport properties and enhancement of bile salt resistance in a heterologous host. | the mrp operon from vibrio cholerae encoding a putative multisubunit na(+)/h(+) antiporter was cloned and functionally expressed in the antiporter-deficient strain of escherichia coli ep432. cells of ep432 expressing vc-mrp exhibited resistance to na(+) and li(+) as well as to natural bile salts such as sodium cholate and taurocholate. when assayed in everted membrane vesicles of the e. coli ep432 host, vc-mrp had sufficiently high antiport activity to facilitate the first extensive analysis of ... | 2009 | 18311075 |
| the vibrio cholerae mrp system: cation/proton antiport properties and enhancement of bile salt resistance in a heterologous host. | the mrp operon from vibrio cholerae encoding a putative multisubunit na(+)/h(+) antiporter was cloned and functionally expressed in the antiporter-deficient strain of escherichia coli ep432. cells of ep432 expressing vc-mrp exhibited resistance to na(+) and li(+) as well as to natural bile salts such as sodium cholate and taurocholate. when assayed in everted membrane vesicles of the e. coli ep432 host, vc-mrp had sufficiently high antiport activity to facilitate the first extensive analysis of ... | 2009 | 18311075 |
| transcription and activities of nox reductases in agrobacterium tumefaciens: the influence of nitrate, nitrite and oxygen availability. | the ability of agrobacetrium tumefaciens to perform balanced transitions from aerobic to anaerobic respiration was studied by monitoring oxygen depletion, transcription of nirk and norb, and the concentrations of nitrite, nitric oxide (no) and nitrous oxide in stirred batch cultures with different initial oxygen, nitrate or nitrite concentrations. nitrate concentrations (0.2-2 mm) did not affect oxygen depletion, nor the oxygen concentration at which denitrification was initiated (1-2 microm). n ... | 2008 | 18312398 |
| rnai-mediated suppression of p-coumaroyl-coa 3'-hydroxylase in hybrid poplar impacts lignin deposition and soluble secondary metabolism. | p-coumaroyl-coa 3'-hydroxylase (c3'h) is a cytochrome p450-dependent monooxygenase that catalyzes the 3'-hydroxylation of p-coumaroyl shikimate and p-coumaroyl quinate. we used rna interference to generate transgenic hybrid poplar suppressed in c3'h expression and analyzed them with respect to transcript abundance, cell wall structure and chemical composition, and soluble metabolite levels. rt-pcr expression profiles confirmed the down-regulation of c3'h in a number of lines, which generally cor ... | 2008 | 18316744 |
| arabidopsis r2r3-myb transcription factor atmyb60 functions as a transcriptional repressor of anthocyanin biosynthesis in lettuce (lactuca sativa). | the myb transcription factors play important roles in the regulation of many secondary metabolites at the transcriptional level. we evaluated the possible roles of the arabidopsis r2r3-myb transcription factors in flavonoid biosynthesis because they are induced by uv-b irradiation but their associated phenotypes are largely unexplored. we isolated their genes by race-pcr, and performed transgenic approach and metabolite analyses in lettuce (lactuca sativa). we found that one member of this prote ... | 2008 | 18317777 |
| functional adaptation of a plant receptor-kinase paved the way for the evolution of intracellular root symbioses with bacteria. | nitrogen-fixing root nodule symbioses (rns) occur in two major forms-actinorhiza and legume-rhizobium symbiosis-which differ in bacterial partner, intracellular infection pattern, and morphogenesis. the phylogenetic restriction of nodulation to eurosid angiosperms indicates a common and recent evolutionary invention, but the molecular steps involved are still obscure. in legumes, at least seven genes-including the symbiosis receptor-kinase gene symrk-are essential for the interaction with rhizob ... | 2008 | 18318603 |
| promoter-proximal introns in arabidopsis thaliana are enriched in dispersed signals that elevate gene expression. | introns that elevate mrna accumulation have been found in a wide range of eukaryotes. however, not all introns affect gene expression, and direct testing is currently the only way to identify stimulatory introns. our genome-wide analysis in arabidopsis thaliana revealed that promoter-proximal introns as a group are compositionally distinct from distal introns and that the degree to which an individual intron matches the promoter-proximal intron profile is a strong predictor of its ability to inc ... | 2008 | 18319396 |
| the arabidopsis thaliana type i isopentenyl diphosphate isomerases are targeted to multiple subcellular compartments and have overlapping functions in isoprenoid biosynthesis. | to form the building blocks of isoprenoids, isopentenyl diphosphate (ipp) isomerase activity, which converts ipp to dimethylallyl diphosphate (dmapp), appears to be necessary in cytosol, plastids, and mitochondria. arabidopsis thaliana contains only two ipp isomerases (isopentenyl diphosphate isomerase1 [idi1] and idi2). both encode proteins with n-terminal extensions similar to transit peptides and are expressed in all organs, with idi1 less abundant than idi2. examination of enhanced green flu ... | 2008 | 18319397 |
| expression of a synthetic cry1ec gene for resistance against spodoptera litura in transgenic peanut (arachis hypogaea l.). | the tobacco cutworm (spodoptera litura) is a polyphagous foliage insect and a major pest on peanut (arachis hypogaea l.). s. litura is susceptible to the chimeric delta-endotoxin cry1ec reported earlier. de-embryonated cotyledon explants of peanut were transformed using agrobacterium tumefaciens strain eha101 harboring a synthetic cry1ec gene driven by the camv 35s promoter. transgenic plants of peanut with a single copy insertion of cry1ec were selected in the t(0) generation by southern blot h ... | 2008 | 18320194 |
| expression of modified gene encoding functional human alpha-1-antitrypsin protein in transgenic tomato plants. | transgenic plants offer promising alternative for large scale, sustainable production of safe, functional, recombinant proteins of therapeutic and industrial importance. here, we report the expression of biologically active human alpha-1-antitrypsin in transgenic tomato plants. the 1,182 bp cdna sequence of human aat was strategically designed, modified and synthesized to adopt codon usage pattern of dicot plants, elimination of mrna destabilizing sequences and modifications around 5' and 3' fla ... | 2008 | 18320339 |
| glycosyltransferase efficiently controls phenylpropanoid pathway. | in a previous study, anthocyanin levels in potato plants were increased by manipulating genes connected with the flavonoid biosynthesis pathway. however, starch content and tuber yield were dramatically reduced in the transgenic plants, which over-expressed dihydroflavonol reductase (dfr). | 2008 | 18321380 |
| a novel methyltransferase methylates cucumber mosaic virus 1a protein and promotes systemic spread. | in mammalian and yeast systems, methyltransferases have been implicated in the regulation of diverse processes, such as protein-protein interactions, protein localization, signal transduction, rna processing, and transcription. the cucumber mosaic virus (cmv) 1a protein is essential not only for virus replication but also for movement. using a yeast two-hybrid system with tobacco plants, we have identified a novel gene encoding a methyltransferase that interacts with the cmv 1a protein and have ... | 2008 | 18321966 |
| arabidopsis ribosomal proteins rpl23aa and rpl23ab are differentially targeted to the nucleolus and are disparately required for normal development. | protein synthesis is catalyzed by the ribosome, a two-subunit enzyme comprised of four ribosomal rnas and, in arabidopsis (arabidopsis thaliana), 81 ribosomal proteins (r-proteins). plant r-protein genes exist as families of multiple expressed members, yet only one r-protein from each family is incorporated into any given ribosome, suggesting that many r-protein genes may be functionally redundant or development/tissue/stress specific. here, we characterized the localization and gene-silencing p ... | 2008 | 18322146 |
| an efficient plant viral expression system generating orally immunogenic norwalk virus-like particles. | virus-like particles (vlps) derived from enteric pathogens like norwalk virus (nv) are well suited to study oral immunization. we previously described stable transgenic plants that accumulate recombinant nv-like particles (rnvs) that were orally immunogenic in mice and humans. the transgenic approach suffers from long generation time and modest level of antigen accumulation. we now overcome these constraints with an efficient tobacco mosaic virus (tmv)-derived transient expression system using l ... | 2008 | 18325641 |
| 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 |
| 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 |
| agrobacterium tumefaciens-mediated transformation of poinsettia, euphorbia pulcherrima, with virus-derived hairpin rna constructs confers resistance to poinsettia mosaic virus. | agrobacterium-mediated transformation for poinsettia (euphorbia pulcherrima willd. ex klotzsch) is reported here for the first time. internode stem explants of poinsettia cv. millenium were transformed by agrobacterium tumefaciens, strain lba 4404, harbouring virus-derived hairpin (hp) rna gene constructs to induce rna silencing-mediated resistance to poinsettia mosaic virus (pnmv). prior to transformation, an efficient somatic embryogenesis system was developed for poinsettia cv. millenium in w ... | 2008 | 18327592 |
| pepper pectin methylesterase inhibitor protein capmei1 is required for antifungal activity, basal disease resistance and abiotic stress tolerance. | pectin is one of the main components of the plant cell wall that functions as the primary barrier against pathogens. among the extracellular pectinolytic enzymes, pectin methylesterase (pme) demethylesterifies pectin, which is secreted into the cell wall in a highly methylesterified form. here, we isolated and functionally characterized the pepper (capsicum annuum l.) gene capmei1, which encodes a pectin methylesterase inhibitor protein (pmei), in pepper leaves infected by xanthomonas campestris ... | 2008 | 18327607 |
| role of chey1 and chey2 in the chemotaxis of a. tumefaciens toward acetosyringone. | agrobacterium tumefaciens has a chemtaxis operon, which includes orf1, orf2, chey1, chea, cher, cheb, chey2, orf9, and orf10. in-frame deletions of chey1 and chey2 were constructed and the chemosensory behavior of the mutants was examined on swarm plates and in a chemotaxis assay toward acetosyringone. the chey2 mutant (c1/dely2) showed impaired chemotactic capabilities in both swarming and chemotaxis assays. the effect of lacking chey1 on chemotaxis is less severe than that of chey2, under the ... | 2008 | 18330636 |
| ethylene production in plants during transformation suppresses vir gene expression in agrobacterium tumefaciens. | ethylene evolution from plants inhibits agrobacterium-mediated genetic transformation, but the mechanism is little understood. in this study, the possible role of ethylene in agrobacterium-mediated genetic transformation was clarified. it was tested whether or not plant ethylene sensitivity affected genetic transformation; the sensitivity might regulate bacterial growth during co-cultivation and vir gene expression in agrobacterium tumefaciens. for these experiments, melon (cucumis melo) was use ... | 2008 | 18331427 |
| integration of light and abscisic acid signaling during seed germination and early seedling development. | seed germination is regulated by endogenous hormonal cues and external environmental stimuli such as water, low temperature, and light. after germination, the young seedling must rapidly establish its root system and the photoautotrophic capability appropriate to its surrounding environment. light and the phytohormone abscisic acid (aba) both regulate seed germination and seedling development, although how light and aba signals are integrated at the molecular level is not understood. here, we fo ... | 2008 | 18332440 |
| the agl62 mads domain protein regulates cellularization during endosperm development in arabidopsis. | endosperm, a storage tissue in the angiosperm seed, provides nutrients to the embryo during seed development and/or to the developing seedling during germination. a major event in endosperm development is the transition between the syncytial phase, during which the endosperm nuclei undergo many rounds of mitosis without cytokinesis, and the cellularized phase, during which cell walls form around the endosperm nuclei. the molecular processes controlling this phase transition are not understood. i ... | 2008 | 18334668 |
| dicer-like2 plays a primary role in transitive silencing of transgenes in arabidopsis. | dicer-like (dcl) enzymes play a pivotal role in rna silencing in plants, processing the long double-stranded rna (dsrna) that triggers silencing into the primary short interfering rnas (sirnas) that mediate it. the sirna population can be augmented and silencing amplified via transitivity, an rna-dependent rna polymerase (rdr)-dependent pathway that uses the target rna as substrate to generate secondary sirnas. here we report that arabidopsis dcl2-but not dcl4-is required for transitivity in cel ... | 2008 | 18335032 |
| scale-up of agrobacterium-mediated transient protein expression in bioreactor-grown nicotiana glutinosa plant cell suspension culture. | the reporter gene beta-glucuronidase was transiently expressed in a 51-l bioreactor-grown plant cell suspension culture of nicotiana glutinosa at a yield of approximately 1.1 mg through co-culture with an auxotrophic strain of agrobacterium tumefaciens. the three order of magnitude scale-up involved the investigation of factors contributing to transient expression including the timing of agrobacterium inoculation relative to the plant cell growth phase, plant tissue culture hormonal triggers and ... | 2008 | 18335952 |
| 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 |
| temperature-induced switch to the pathogenic yeast form of histoplasma capsulatum requires ryp1, a conserved transcriptional regulator. | histoplasma capsulatum, a fungal pathogen of humans, switches from a filamentous spore-forming mold in the soil to a pathogenic budding-yeast form in the human host. this morphologic switch, which is exhibited by h. capsulatum and a group of evolutionarily related fungal pathogens, is regulated by temperature. using insertional mutagenesis, we identified a gene, ryp1 (required for yeast phase growth), which is required for yeast-form growth at 37 degrees c. ryp1 mutants are constitutively filame ... | 2008 | 18339808 |
| the coiled-coil and nucleotide binding domains of the potato rx disease resistance protein function in pathogen recognition and signaling. | plant genomes encode large numbers of nucleotide binding and leucine-rich repeat (nb-lrr) proteins, some of which mediate the recognition of pathogen-encoded proteins. following recognition, the initiation of a resistance response is thought to be mediated by the domains present at the n termini of nb-lrr proteins, either a toll and interleukin-1 receptor or a coiled-coil (cc) domain. in order to understand the role of the cc domain in nb-lrr function, we have undertaken a systematic structure-f ... | 2008 | 18344282 |
| emb2473/miro1, an arabidopsis miro gtpase, is required for embryogenesis and influences mitochondrial morphology in pollen. | the regulation of mitochondrial biogenesis, subcellular distribution, morphology, and metabolism are essential for all aspects of plant growth and development. however, the molecular mechanisms involved are still unclear. here, we describe an analysis of the three arabidopsis thaliana orthologs of the evolutionarily conserved miro gtpases. two of the genes, miro1 and miro2, are transcribed ubiquitously throughout the plant tissues, and their gene products localize to mitochondria via their c-ter ... | 2008 | 18344283 |
| opine-based agrobacterium competitiveness: dual expression control of the agrocinopine catabolism (acc) operon by agrocinopines and phosphate levels. | agrobacterium tumefaciens strain c58 can transform plant cells to produce and secrete the sugar-phosphate conjugate opines agrocinopines a and b. the bacterium then moves in response to the opines and utilizes them as exclusive sources of carbon, energy, and phosphate via the functions encoded by the acc operon. these privileged opine-involved activities contribute to the formation of agrobacterial niches in the environment. we found that the expression of the acc operon is induced by agrocinopi ... | 2008 | 18344359 |
| 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 |
| 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 |
| lectr2, a ctr1-like protein kinase from tomato, plays a role in ethylene signalling, development and defence. | arabidopsis atctr1 is a raf-like protein kinase that interacts with etr1 and ers and negatively regulates ethylene responses. in tomato, several ctr1-like proteins could perform this role. we have characterized lectr2, which has similarity to atctr1 and also to edr1, a ctr1-like arabidopsis protein involved in defence and stress responses. protein-protein interactions between lectr2 and six tomato ethylene receptors indicated that lectr2 interacts preferentially with the subfamily i etr1-type et ... | 2008 | 18346193 |
| the redox switch of gamma-glutamylcysteine ligase via a reversible monomer-dimer transition is a mechanism unique to plants. | in plants, the first committed enzyme for glutathione biosynthesis, gamma-glutamylcysteine ligase (gcl), is under multiple controls. the recent elucidation of gcl structure from brassica juncea (bjgcl) has revealed the presence of two intramolecular disulfide bridges (cc1, cc2), which both strongly impact on gcl activity in vitro. here we demonstrate that cysteines of cc1 are confined to plant species from the rosids clade, and are absent in other plant families. conversely, cysteines of cc2 inv ... | 2008 | 18346196 |
| proteomic analysis of the ehv-86 virion. | emiliania huxleyi virus 86 (ehv-86) is the type species of the genus coccolithovirus within the family phycodnaviridae. the fully sequenced 407,339 bp genome is predicted to encode 473 protein coding sequences (cdss) and is the largest phycodnaviridae sequenced to date. the majority of ehv-86 cdss exhibit no similarity to proteins in the public databases. | 2008 | 18346272 |
| hypocotyl-based agrobacterium-mediated transformation of soybean (glycine max) and application for rna interference. | an efficient system of gene transformation is necessary for soybean [glycine max (l.) merrill] functional genomics and gene modification by using rna interference (rnai) technology. to establish such system, we improved the conditions of tissue culture and transformation for increasing the frequency of adventitious shoots and decreasing the browning and necrosis of hypocotyls. adding n(6)-benzylaminopurine (bap) and silver nitrate in culture medium enhanced the shoot formation on hypocotyls. bap ... | 2008 | 18347801 |
| cellulose synthesis in phytophthora infestans is required for normal appressorium formation and successful infection of potato. | cellulose, the important structural compound of cell walls, provides strength and rigidity to cells of numerous organisms. here, we functionally characterize four cellulose synthase genes (cesa) in the oomycete plant pathogen phytophthora infestans, the causal agent of potato (solanum tuberosum) late blight. three members of this new protein family contain pleckstrin homology domains and form a distinct phylogenetic group most closely related to the cellulose synthases of cyanobacteria. expressi ... | 2008 | 18349153 |
| comparative analysis of acinetobacters: three genomes for three lifestyles. | acinetobacter baumannii is the source of numerous nosocomial infections in humans and therefore deserves close attention as multidrug or even pandrug resistant strains are increasingly being identified worldwide. here we report the comparison of two newly sequenced genomes of a. baumannii. the human isolate a. baumannii aye is multidrug resistant whereas strain sdf, which was isolated from body lice, is antibiotic susceptible. as reference for comparison in this analysis, the genome of the soil- ... | 2008 | 18350144 |
| a built-in strategy for containment of transgenic plants: creation of selectively terminable transgenic rice. | plant transgenic technology has been widely utilized for engineering crops for trait improvements and for production of high value proteins such as pharmaceuticals. however, the unintended spreading of commercial transgenic crops by pollination and seed dispersal is a major concern for environmental and food safety. simple and reliable containment strategies for transgenes are highly desirable. here we report a novel method for creating selectively terminable transgenic rice. in this method, the ... | 2008 | 18350155 |
| highly specific gene silencing by artificial mirnas in rice. | endogenous micrornas (mirnas) are potent negative regulators of gene expression in plants and animals. artificial mirnas (amirnas)-designed to target one or several genes of interest-provide a new and highly specific approach for effective post-transcriptional gene silencing (ptgs) in plants. | 2008 | 18350165 |
| transient expression of homologous hairpin rna interferes with pvy transmission by aphids. | hairpin rnas have been used to confer resistance to viruses in plants through rna silencing. however, it has not been demonstrated that rna silencing was effective against inoculation by aphids of non-persistently transmitted viruses, the major route of plant virus spread in nature. as a proof-of-principle strategy, we made use of agrobacterium tumefaciens to transiently express a hairpin rna homologous to potato virus y (pvy) in plant tissues. a complete and specific interference with aphid tra ... | 2008 | 18353170 |
| structural insight into the mechanism of substrate specificity and catalytic activity of an hd-domain phosphohydrolase: the 5'-deoxyribonucleotidase yfbr from escherichia coli. | hd-domain phosphohydrolases have nucleotidase and phosphodiesterase activities and play important roles in the metabolism of nucleotides and in signaling. we present three 2.1-a-resolution crystal structures (one in the free state and two complexed with natural substrates) of an hd-domain phosphohydrolase, the escherichia coli 5'-nucleotidase yfbr. the free-state structure of yfbr contains a large cavity accommodating the metal-coordinating hd motif (h33, h68, d69, and d137) and other conserved ... | 2008 | 18353368 |
| 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 |
| the arabidopsis putative selenium-binding protein family: expression study and characterization of sbp1 as a potential new player in cadmium detoxification processes. | in arabidopsis (arabidopsis thaliana), the putative selenium-binding protein (sbp) gene family is composed of three members (sbp1-sbp3). reverse transcription-polymerase chain reaction analyses showed that sbp1 expression was ubiquitous. sbp2 was expressed at a lower level in flowers and roots, whereas sbp3 transcripts were only detected in young seedling tissues. in cadmium (cd)-treated seedlings, sbp1 level of expression was rapidly increased in roots. in shoots, sbp1 transcripts accumulated l ... | 2008 | 18354042 |
| a biaryl xanthone derivative having axial chirality from penicillium vinaceum. | a new xanthone derivative having axial chirality was isolated from penicillium vinaceum. owing to the axial chirality, its structure, including absolute configuration, was determined by means of extensive spectroscopic data, such as uv, ir, ms, and 1d and 2d nmr spectra, and computational chiroptical methods. the new compound, (a r)-2'-methoxyvinaxanthone, has a structure containing two aromatic moieties with substituents hindering rotation about the biaryl axis. the compound gave positive resul ... | 2008 | 18355033 |
| structural analysis of adp-glucose pyrophosphorylase from the bacterium agrobacterium tumefaciens. | adp-glucose pyrophosphorylase (adpglc ppase) catalyzes the conversion of glucose 1-phosphate and atp to adp-glucose and pyrophosphate. as a key step in glucan synthesis, the adpglc ppases are highly regulated by allosteric activators and inhibitors in accord with the carbon metabolism pathways of the organism. crystals of agrobacterium tumefaciens adpglc ppase were obtained using lithium sulfate as a precipitant. a complete anomalous selenomethionyl derivative x-ray diffraction data set was coll ... | 2008 | 18355040 |
| involvement of arabidopsis hos15 in histone deacetylation and cold tolerance. | histone modification in chromatin is one of the key control points in gene regulation in eukaryotic cells. protein complexes composed of histone acetyltransferase or deacetylase, wd40 repeat protein, and many other components have been implicated in this process. here, we report the identification and functional characterization of hos15, a wd40-repeat protein crucial for repression of genes associated with abiotic stress tolerance through histone deacetylation in arabidopsis. hos15 shares high ... | 2008 | 18356294 |
| purification of two putative type ii nadh dehydrogenases with different substrate specificities from alkaliphilic bacillus pseudofirmus of4. | a putative type ii nadh dehydrogenase from halobacillus dabanensis was recently reported to have na+/h+ antiport activity (and called nap), raising the possibility of direct coupling of respiration to antiport-dependent ph homeostasis. this study characterized a homologous type ii nadh dehydrogenase of genetically tractable alkaliphilic bacillus pseudofirmus of4, in which evidence supports antiport-based ph homeostasis that is mediated entirely by secondary antiport. two candidate type ii nadh d ... | 2008 | 18359284 |
| comparative genome analysis of "candidatus phytoplasma australiense" (subgroup tuf-australia i; rp-a) and "ca. phytoplasma asteris" strains oy-m and ay-wb. | the chromosome sequence of "candidatus phytoplasma australiense" (subgroup tuf-australia i; rp-a), associated with dieback in papaya, australian grapevine yellows in grapevine, and several other important plant diseases, was determined. the circular chromosome is represented by 879,324 nucleotides, a gc content of 27%, and 839 protein-coding genes. five hundred two of these protein-coding genes were functionally assigned, while 337 genes were hypothetical proteins with unknown function. potentia ... | 2008 | 18359806 |
| extended function of plasmid partition genes: the sop system of linear phage-plasmid n15 facilitates late gene expression. | the mitotic stability of the linear plasmid-prophage n15 of escherichia coli depends on a partition system closely related to that of the f plasmid sopabc. the two sop systems are distinguished mainly by the arrangement of their centromeric sopb-binding sites, clustered in f (sopc) and dispersed in n15 (ir1 to ir4). because two of the n15 inverted repeat (ir) sites are located close to elements presumed (by analogy with phage lambda) to regulate late gene expression during the lytic growth of n1 ... | 2008 | 18359814 |
| 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 |
| 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 |
| the ionic environment controls the contribution of the barley hvhak1 transporter to potassium acquisition. | the control of potassium (k+) acquisition is a critical requirement for plant growth. although hak1 (high affinity k+ 1) transporters provide a pathway for k+ acquisition, the effect exerted by the ionic environment on their contribution to k+ capture remains essentially unknown. here, the influence of the ionic environment on the accumulation of transcripts coding for the barley (hordeum vulgare) hvhak1 transporter as well as on hvhak1-mediated k+ capture has been examined. in situ mrna hybridi ... | 2008 | 18359846 |
| characterization of cold-responsive extracellular chitinase in bromegrass cell cultures and its relationship to antifreeze activity. | a cold-responsive chitinase gene, bicht1, was isolated from bromegrass (bromus inermis) 'manchar' suspension cells. bicht1 messenger rna was detected at low levels in nonstressed bromegrass cells, whereas its accumulation was induced by incubation at 10 degrees c and 4 degrees c as detected by northern- and western-blot analyses. bicht1 was highly homologous to rye cht9, known to encode an antifreeze protein. bicht1 was overexpressed in escherichia coli and bromegrass cells using genetic transfo ... | 2008 | 18359848 |
| hysteretic and graded responses in bacterial two-component signal transduction. | bacterial two-component systems (tcs) are key signal transduction networks regulating global responses to environmental change. environmental signals may modulate the phosphorylation state of sensor kinases (sk). the phosphorylated sk transfers the phosphate to its cognate response regulator (rr), which causes physiological response to the signal. frequently, the sk is bifunctional and, when unphosphorylated, it is also capable of dephosphorylating the rr. the phosphatase activity may also be mo ... | 2008 | 18363790 |
| haplo-insufficiency of mpk3 in mpk6 mutant background uncovers a novel function of these two mapks in arabidopsis ovule development. | the plant life cycle includes diploid sporophytic and haploid gametophytic generations. female gametophytes (embryo sacs) in higher plants are embedded in specialized sporophytic structures (ovules). here, we report that two closely related mitogen-activated protein kinases in arabidopsis thaliana, mpk3 and mpk6, share a novel function in ovule development: in the mpk6 mutant background, mpk3 is haplo-insufficient, giving female sterility when heterozygous. by contrast, in the mpk3 mutant backgr ... | 2008 | 18364464 |
| exclusion of a proton atpase from the apical membrane is associated with cell polarity and tip growth in nicotiana tabacum pollen tubes. | polarized growth in pollen tubes results from exocytosis at the tip and is associated with conspicuous polarization of ca(2+), h(+), k(+), and cl(-) -fluxes. here, we show that cell polarity in nicotiana tabacum pollen is associated with the exclusion of a novel pollen-specific h(+)-atpase, nt aha, from the growing apex. nt aha colocalizes with extracellular h(+) effluxes, which revert to influxes where nt aha is absent. fluorescence recovery after photobleaching analysis showed that nt aha move ... | 2008 | 18364468 |
| genome mapping and molecular breeding of tomato. | the cultivated tomato, lycopersicon esculentum, is the second most consumed vegetable worldwide and a well-studied crop species in terms of genetics, genomics, and breeding. it is one of the earliest crop plants for which a genetic linkage map was constructed, and currently there are several molecular maps based on crosses between the cultivated and various wild species of tomato. the high-density molecular map, developed based on an l. esculentum x l. pennellii cross, includes more than 2200 ma ... | 2007 | 18364989 |
| plant adaptation to fluctuating environment and biomass production are strongly dependent on guard cell potassium channels. | at least four genes encoding plasma membrane inward k+ channels (k(in) channels) are expressed in arabidopsis guard cells. a double mutant plant was engineered by disruption of a major k(in) channel gene and expression of a dominant negative channel construct. using the patch-clamp technique revealed that this mutant was totally deprived of guard cell k(in) channel (gck(in)) activity, providing a model to investigate the roles of this activity in the plant. gck(in) activity was found to be an es ... | 2008 | 18367672 |
| 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 |
| in planta transformation of notocactus scopa cv. soonjung by agrobacterium tumefaciens. | notocactus scopa cv. soonjung was subjected to in planta agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. the pin-pricking combined with vacuum infiltration (20-30 cmhg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uida and nptii genes was detected in transformed cactus. the established in planta transformation technique generated a transgenic cactus with higher transformati ... | 2008 | 18368411 |