Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| histone monoubiquitination1 interacts with a subunit of the mediator complex and regulates defense against necrotrophic fungal pathogens in arabidopsis. | this work examines the role of the arabidopsis thaliana ring e3 ligase, histone monoubiquitination1 (hub1) in disease resistance. loss-of-function alleles of hub1 show increased susceptibility to the necrotrophic fungal pathogens botrytis cinerea and alternaria brassicicola, whereas hub1 overexpression conferred resistance to b. cinerea. by contrast, responses to the bacterial pathogen pseudomonas syringae are unaltered in hub1 plants. hub1 mutants have thinner cell walls but increased callose a ... | 2009 | 19286969 |
| role of polyisoprenoids in tobacco resistance against biotic stresses. | infection with avirulent pathogens, tobacco mosaic virus (tmv) or pseudomonas syringae pv. tabaci induced accumulation of polyisoprenoid alcohols, solanesol and a family of polyprenols [from polyprenol composed of 14 isoprene units (pren-14) to -18, with pren-16 dominating] in the leaves of resistant tobacco plants nicotiana tabacum cv. samsun nn. upon tmv infection, solanesol content was increased seven- and eight-fold in the inoculated and upper leaves, respectively, while polyprenol content w ... | 2009 | 19292825 |
| a compatible interaction of alternaria brassicicola with arabidopsis thaliana ecotype dig: evidence for a specific transcriptional signature. | the interaction of arabidopsis with alternaria brassicicola provides a model for disease caused by necrotrophs, but a drawback has been the lack of a compatible pathosystem. infection of most ecotypes, including the widely-studied line col-0, with this pathogen generally leads to a lesion that does not expand beyond the inoculated area. this study examines an ecotype, dijon g (dig), which is considered sensitive to a. brassicicola. | 2009 | 19296849 |
| enhanced defense responses in arabidopsis induced by the cell wall protein fractions from pythium oligandrum require sgt1, rar1, npr1 and jar1. | the cell wall protein fraction (cwp) is purified from the non-pathogenic biocontrol agent pythium oligandrum and is composed of two glycoproteins (pod-1 and pod-2), which are structurally similar to class iii elicitins. in tomato plants treated with cwp, jasmonic acid (ja)- and ethylene (et)-dependent signaling pathways are activated, and resistance to ralstonia solanaceraum is enhanced. to dissect cwp-induced defense mechanisms, we investigated defense gene expression and resistance to bacteria ... | 2009 | 19304739 |
| the synthetic elicitor 3,5-dichloroanthranilic acid induces npr1-dependent and npr1-independent mechanisms of disease resistance in arabidopsis. | immune responses of arabidopsis (arabidopsis thaliana) are at least partially mediated by coordinated transcriptional up-regulation of plant defense genes, such as the late/sustained up-regulation in response to hyaloperonospora parasitica (lurp) cluster. we found a defined region in the promoter of the lurp member cabp22 to be important for this response. using a cabp22 promoter-reporter fusion, we have established a robust and specific high-throughput screening system for synthetic defense eli ... | 2009 | 19304930 |
| influence of nemaguard and lovell rootstocks and macroposthonia xenoplax on bacterial canker of peach. | 'fay elberta' peach trees grown on either 'lovell' or 'nemaguard' rootstocks in sandy soil in a lathhouse were highly susceptible to bacterial canker if inoculated with the nematode macroposthonia xenoplax and the bacterium pseudomonas syringae. if either one of these organisms were omitted, serious bacterial canker did not develop. cankers appeared later and remained small when nematodes were omined. very few cankers appeared on trees not inoculated with the bacterium. peach trees on both roots ... | 1977 | 19305599 |
| campylobacter jejuni glycosylation island important in cell charge, legionaminic acid biosynthesis, and colonization of chickens. | previously, we identified five genes (cj1321 to cj1326, of which cj1325 and cj1326 are a single gene) in the o-linked flagellin glycosylation island that are highly prevalent in campylobacter jejuni isolates from chickens. we report mutagenesis, functional, and structural data to confirm that this locus, and cj1324 in particular, has a significant contributory role in the colonization of chickens by c. jejuni. a motile deltacj1324 mutant with intact flagella was considerably less hydrophobic and ... | 2009 | 19307210 |
| structure of thermotoga maritima tm0439: implications for the mechanism of bacterial gntr transcription regulators with zn2+-binding fcd domains. | the gntr superfamily of dimeric transcription factors, with more than 6200 members encoded in bacterial genomes, are characterized by n-terminal winged-helix dna-binding domains and diverse c-terminal regulatory domains which provide a basis for the classification of the constituent families. the largest of these families, fadr, contains nearly 3000 proteins with all-alpha-helical regulatory domains classified into two related pfam families: fadr_c and fcd. only two crystal structures of fadr-fa ... | 2009 | 19307717 |
| cycle inhibiting factors (cifs) are a growing family of functional cyclomodulins present in invertebrate and mammal bacterial pathogens. | the cycle inhibiting factor (cif) produced by enteropathogenic and enterohemorrhagic escherichia coli was the first cyclomodulin to be identified that is injected into host cells via the type iii secretion machinery. cif provokes cytopathic effects characterized by g(1) and g(2) cell cycle arrests, accumulation of the cyclin-dependent kinase inhibitors (ckis) p21(waf1/cip1) and p27(kip1) and formation of actin stress fibres. the x-ray crystal structure of cif revealed it to be a divergent member ... | 2009 | 19308257 |
| mitogen-activated protein kinases 3 and 6 are required for full priming of stress responses in arabidopsis thaliana. | in plants and animals, induced resistance (ir) to biotic and abiotic stress is associated with priming of cells for faster and stronger activation of defense responses. it has been hypothesized that cell priming involves accumulation of latent signaling components that are not used until challenge exposure to stress. however, the identity of such signaling components has remained elusive. here, we show that during development of chemically induced resistance in arabidopsis thaliana, priming is a ... | 2009 | 19318610 |
| disruption of glycosylphosphatidylinositol-anchored lipid transfer protein gene altered cuticular lipid composition, increased plastoglobules, and enhanced susceptibility to infection by the fungal pathogen alternaria brassicicola. | all aerial parts of vascular plants are covered with cuticular waxes, which are synthesized by extensive export of intracellular lipids from epidermal cells to the surface. although it has been suggested that plant lipid transfer proteins (ltps) are involved in cuticular lipid transport, the in planta evidence is still not clear. in this study, a glycosylphosphatidylinositol-anchored ltp (ltpg1) showing higher expression in epidermal peels of stems than in stems was identified from an arabidopsi ... | 2009 | 19321705 |
| genetic dissection of verticillium wilt resistance mediated by tomato ve1. | vascular wilt diseases caused by soil-borne pathogens are among the most devastating plant diseases worldwide. the verticillium genus includes vascular wilt pathogens with a wide host range. although v. longisporum infects various hosts belonging to the cruciferaceae, v. dahliae and v. albo-atrum cause vascular wilt diseases in over 200 dicotyledonous species, including economically important crops. a locus responsible for resistance against race 1 strains of v. dahliae and v. albo-atrum has bee ... | 2009 | 19321708 |
| evolutionary history and stress regulation of plant receptor-like kinase/pelle genes. | receptor-like kinase (rlk)/pelle genes play roles ranging from growth regulation to defense response, and the dramatic expansion of this family has been postulated to be crucial for plant-specific adaptations. despite this, little is known about the history of or the factors that contributed to the dramatic expansion of this gene family. in this study, we show that expansion coincided with the establishment of land plants and that rlk/pelle subfamilies were established early in land plant evolut ... | 2009 | 19321712 |
| phylogenetic analysis, subcellular localization, and expression patterns of rpd3/hda1 family histone deacetylases in plants. | although histone deacetylases from model organisms have been previously identified, there is no clear basis for the classification of histone deacetylases under the rpd3/hda1 superfamily, particularly on plants. thus, this study aims to reconstruct a phylogenetic tree to determine evolutionary relationships between rpd3/hda1 histone deacetylases from six different plants representing dicots with arabidopsis thaliana, populus trichocarpa, and pinus taeda, monocots with oryza sativa and zea mays, ... | 2009 | 19327164 |
| methyl salicylate production and jasmonate signaling are not essential for systemic acquired resistance in arabidopsis. | systemic acquired resistance (sar) develops in response to local microbial leaf inoculation and renders the whole plant more resistant to subsequent pathogen infection. accumulation of salicylic acid (sa) in noninfected plant parts is required for sar, and methyl salicylate (mesa) and jasmonate (ja) are proposed to have critical roles during sar long-distance signaling from inoculated to distant leaves. here, we address the significance of mesa and ja during sar development in arabidopsis thalia ... | 2009 | 19329558 |
| an adenosine kinase exists in xanthomonas campestris pathovar campestris and is involved in extracellular polysaccharide production, cell motility, and virulence. | adenosine kinase (adk) is a purine salvage enzyme and a typical housekeeping enzyme in eukaryotes which catalyzes the phosphorylation of adenosine to form amp. since prokaryotes synthesize purines de novo and no endogenous adk activity is detectable in escherichia coli, adk has long been considered to be rare in bacteria. to date, only two prokaryotes, both of which are gram-positive bacteria, have been reported to contain adk. here we report that the gram-negative bacterium xanthomonas campestr ... | 2009 | 19329636 |
| endophytic colonization of potato (solanum tuberosum l.) by a novel competent bacterial endophyte, pseudomonas putida strain p9, and its effect on associated bacterial communities. | pseudomonas putida strain p9 is a novel competent endophyte from potato. p9 causes cultivar-dependent suppression of phytophthora infestans. colonization of the rhizoplane and endosphere of potato plants by p9 and its rifampin-resistant derivative p9r was studied. the purposes of this work were to follow the fate of p9 inside growing potato plants and to establish its effect on associated microbial communities. the effects of p9 and p9r inoculation were studied in two separate experiments. the r ... | 2009 | 19329656 |
| bypassing kinase activity of the tomato pto resistance protein with small molecule ligands. | the tomato (solanum lycopersicum) protein kinase pto confers resistance to pseudomonas syringae pv. tomato bacteria expressing the avrpto and avrptob effector proteins. pto specifically recognizes both effectors by direct physical interactions triggering activation of immune responses. here, we used a chemical-genetic approach to sensitize pto to analogs of pp1, an atp-competitive small molecule inhibitor. by using pp1 analogs in combination with the sensitized pto (pto(as)), we examined the rol ... | 2009 | 19332544 |
| genetic exchange of multidrug efflux pumps among two enterobacterial species with distinctive ecological niches. | acrab-tolc is the major multidrug efflux system in enterobacteriaceae recognizing structurally unrelated molecules including antibiotics, dyes, and detergents. additionally, in escherichia coli it mediates resistance to bile salts. in the plant pathogen erwinia amylovora acrab-tolc is required for virulence and phytoalexin resistance. exchange analysis of acrab-tolc was conducted by complementing mutants of both species defective in acrb or tolc with alleles from either species. the acrb and tol ... | 2009 | 19333425 |
| fully automated chip-based negative mode nanoelectrospray mass spectrometry of fructooligosaccharides produced by heterologously expressed levansucrase from pseudomonas syringae pv. tomato dc3000. | pseudomonas syringae pathovars possess multiple levansucrases with still unclear specific roles for bacteria. we have cloned and expressed three levansucrase genes, lsc1, lsc2 and lsc3, from p. syringae dc3000 in escherichia coli. levansucrases synthesize a high molecular weight fructan polymer, levan, from sucrose and in the case of some levansucrases, fructooligosaccharides (fos) with potential prebiotic effects are also produced. the ability of purified lsc3 protein of dc3000 to synthesize fo ... | 2009 | 19337979 |
| acyl-homoserine lactone-mediated cross talk among epiphytic bacteria modulates behavior of pseudomonas syringae on leaves. | the leaf surface harbors a host of bacterial epiphytes that are capable of influencing the quorum sensing (qs) system of the plant pathogen pseudomonas syringae pv. syringae (pss). pss uses qs to regulate expression of genes conferring extracellular polysaccharide production, motility and factors contributing to virulence to plants. about 7% of bacterial epiphytes isolated in this study produce the pss cognate signal, 3-oxohexanoyl-homoserine lactone (3oc6hsl), often in amounts more than 10-fold ... | 2009 | 19340082 |
| influence of arabidopsis thaliana accessions on rhizobacterial communities and natural variation in root exudates. | plant species is considered to be one of the most important factors in shaping rhizobacterial communities, but specific plant-microbe interactions in the rhizosphere are still not fully understood. arabidopsis thaliana, for which a large number of naturally occurring ecotype accessions exist, lacks mycorrhizal associations and is hence an ideal model for rhizobacterial studies. eight arabidopsis accessions were found to exert a marked selective influence on bacteria associated with their roots, ... | 2009 | 19342429 |
| priming in systemic plant immunity. | plants possess inducible systemic defense responses when locally infected by pathogens. bacterial infection results in the increased accumulation of the mobile metabolite azelaic acid, a nine-carbon dicarboxylic acid, in the vascular sap of arabidopsis that confers local and systemic resistance against the pathogen pseudomonas syringae. azelaic acid primes plants to accumulate salicylic acid (sa), a known defense signal, upon infection. mutation of the azelaic acid induced 1 (azi1) gene, which i ... | 2009 | 19342588 |
| a family of bacterial cysteine protease type iii effectors utilizes acylation-dependent and -independent strategies to localize to plasma membranes. | bacterial phytopathogens employ a type iii secretion system to deliver effector proteins into the plant cell to suppress defense pathways; however, the molecular mechanisms and subcellular localization strategies that drive effector function largely remain a mystery. here, we demonstrate that the plant plasma membrane is the primary site for subcellular localization of the pseudomonas syringae effector avrpphb and five additional cysteine protease family members. avrpphb and two avrpphb-like eff ... | 2009 | 19346252 |
| human- and plant-pathogenic pseudomonas species produce bacteriocins exhibiting colicin m-like hydrolase activity towards peptidoglycan precursors. | genes encoding proteins that exhibit similarity to the c-terminal domain of escherichia coli colicin m were identified in the genomes of some pseudomonas species, namely, p. aeruginosa, p. syringae, and p. fluorescens. these genes were detected only in a restricted number of strains. in p. aeruginosa, for instance, the colicin m homologue gene was located within the exou-containing genomic island a, a large horizontally acquired genetic element and virulence determinant. here we report the cloni ... | 2009 | 19346308 |
| arabidopsis actin-depolymerizing factor atadf4 mediates defense signal transduction triggered by the pseudomonas syringae effector avrpphb. | the actin cytoskeleton has been implicated in plant defenses against pathogenic fungi and oomycetes with limited, indirect evidence. to date, there are no reports linking actin with resistance against phytopathogenic bacteria. the dynamic behavior of actin filaments is regulated by a diverse array of actin-binding proteins, among which is the actin-depolymerizing factor (adf) family of proteins. here, we demonstrate that actin dynamics play a role in the activation of gene-for-gene resistance in ... | 2009 | 19346440 |
| analysis of temperature modulation of plant defense against biotrophic microbes. | plant-pathogen interactions are known to be affected by environmental factors including temperature; however, the temperature effects have not been systematically studied in plant disease resistance. here, we characterized the effects of a moderate increase in temperature on resistance to bacterial pathogen pseudomonas syringae and two viral elicitors in arabidopsis thaliana and nicotiana benthamiana. both the basal and the resistance (r) gene-mediated defense responses to pseudomonas syringae a ... | 2009 | 19348568 |
| over-expression of a tomato n-acetyl-l-glutamate synthase gene (slnags1) in arabidopsis thaliana results in high ornithine levels and increased tolerance in salt and drought stresses. | a single copy of the n-acetyl-l-glutamate synthase gene (slnags1) has been isolated from tomato. the deduced amino acid sequence consists of 604 amino acids and shows a high level of similarity to the predicted arabidopsis nags1 and nags2 proteins. furthermore, the n-terminus argb domain and the c-terminus arga domain found in slnags1 are similar to the structural arrangements that have been reported for other predicted nags proteins. slnags1 was expressed at high levels in all aerial organs, an ... | 2009 | 19357433 |
| novel succinylated and large-sized osmoregulated periplasmic glucans of pseudomonas syringae pv. syringae. | osmoregulated periplasmic glucans (opgs) are intrinsic components of the gram-negative bacterial envelope and are important for bacterial-host interactions. the opgs of pseudomonas syringae pv. syringae have been known to be highly branched linear glucans ranging from 6 to 13 glucose residues devoid of any substituents, while having backbone structure similar to those of escherichia coli and erwinia chrysanthemi. here, we report for the first time succinylated and large-sized opgs from p. syring ... | 2009 | 19358981 |
| synthetic and structural studies on syringolin a and b reveal critical determinants of selectivity and potency of proteasome inhibition. | syrbactins, a family of natural products belonging either to the syringolin or glidobactin class, are highly potent proteasome inhibitors. although sharing similar structural features, they differ in their macrocyclic lactam core structure and exocyclic side chain. these structural variations critically influence inhibitory potency and proteasome subsite selectivity. here, we describe the total synthesis of syringolin a and b, which together with enzyme kinetic and structural studies, allowed us ... | 2009 | 19359491 |
| arabidopsis chloroplastic glutathione peroxidases play a role in cross talk between photooxidative stress and immune responses. | glutathione peroxidases (gpxs; ec 1.11.1.9) are key enzymes of the antioxidant network in plants and animals. in order to investigate the role of antioxidant systems in plant chloroplasts, we generated arabidopsis (arabidopsis thaliana) transgenic lines that are depleted specifically in chloroplastic (cp) forms of gpx1 and gpx7. we show that reduced cpgpx expression, either in transgenic lines with lower total cpgpx expression (gpx1 and gpx7) or in a gpx7 insertion mutant, leads to compromised p ... | 2009 | 19363092 |
| a high-resolution map of the grp1 locus on chromosome v of potato harbouring broad-spectrum resistance to the cyst nematode species globodera pallida and globodera rostochiensis. | the grp1 locus confers broad-spectrum resistance to the potato cyst nematode species globodera pallida and globodera rostochiensis and is located in the gp21-gp179 interval on the short arm of chromosome v of potato. a high-resolution map has been developed using the diploid mapping population rham026, comprising 1,536 genotypes. the flanking markers gp21 and gp179 have been used to screen the 1,536 genotypes for recombination events. interval mapping of the resistances to g. pallida pa2 and g. ... | 2009 | 19363662 |
| use of buckwheat seed protease inhibitor gene for improvement of tobacco and potato plant resistance to biotic stress. | the possibility to use agrobacterial transformation of leaf discs to produce resistance to bacterial infections in tobacco and potato plants by introduction of a single gene encoding the serine proteinase inhibitor bwi-1a (isp) from buckwheat seeds is shown. all studied pcr-positive transgenic plants exhibited antibacterial activity in biotests. it was shown that the presence of just a single gene of serine proteinase inhibitor provides sufficient protection at least against two bacterial phytop ... | 2009 | 19364319 |
| this is not your mother's repressor: the complex role of fur in pathogenesis. | 2009 | 19364842 | |
| xanthomonas t3s effector xopn suppresses pamp-triggered immunity and interacts with a tomato atypical receptor-like kinase and tft1. | xopn is a virulence factor from xanthomonas campestris pathovar vesicatoria (xcv) that is translocated into tomato (solanum lycopersicum) leaf cells by the pathogen's type iii secretion system. xcv deltaxopn mutants are impaired in growth and have reduced ability to elicit disease symptoms in susceptible tomato leaves. we show that xopn action in planta reduced pathogen-associated molecular pattern (pamp)-induced gene expression and callose deposition in host tissue, indicating that xopn suppres ... | 2009 | 19366901 |
| on the quaternary association of the type iii secretion system hrcqb-c protein: experimental evidence differentiates among the various oligomerization models. | the hrcqb protein from the plant pathogen pseudomonas syringae is a core component of the bacterial type iii secretion apparatus. the core consists of nine proteins widely conserved among animal and plant pathogens which also share sequence and structural similarities with proteins from the bacterial flagellum. previous studies of the carboxy-terminal domain of hrcqb (hrcqb-c) and its flagellar homologue, flin-c, have revealed extensive sequence and structural homologies, similar subcellular loc ... | 2009 | 19374021 |
| structural analysis of catalase from two musa accessions, fhia18 and williams, and from ravenala madagascariensis. | nucleotide sequences of catalase were obtained following amplification using specific primers and were blasted against musa acuminata catalase 2 mrna from ncbi (157418810). clustering of the amino acid sequences from ncbi was done using clustal x. the latter revealed that fhia18 catalase is more related to ravenala madagascariensis (musa relative) catalase while the williams catalase is more related to a clade containing a musa acuminata (musa ancestor) catalase from ncbi. the tertiary structure ... | 2008 | 19374128 |
| quorum-sensing control of antibiotic synthesis in burkholderia thailandensis. | the genome of burkholderia thailandensis codes for several luxr-luxi quorum-sensing systems. we used b. thailandensis quorum-sensing deletion mutants and recombinant escherichia coli to determine the nature of the signals produced by one of the systems, btar2-btai2, and to show that this system controls genes required for the synthesis of an antibiotic. btai2 is an acyl-homoserine lactone (acyl-hsl) synthase that produces two hydroxylated acyl-hsls, n-3-hydroxy-decanoyl-hsl (3ohc(10)-hsl) and n- ... | 2009 | 19376863 |
| misexpression of fatty acid elongation1 in the arabidopsis epidermis induces cell death and suggests a critical role for phospholipase a2 in this process. | very-long-chain fatty acids (vlcfas) are important functional components of various lipid classes, including cuticular lipids in the higher plant epidermis and lipid-derived second messengers. here, we report the characterization of transgenic arabidopsis thaliana plants that epidermally express fatty acid elongation1 (fae1), the seed-specific beta-ketoacyl-coa synthase (kcs) catalyzing the first rate-limiting step in vlcfa biosynthesis. misexpression of fae1 changes the vlcfas in different clas ... | 2009 | 19376931 |
| leucine aminopeptidase regulates defense and wound signaling in tomato downstream of jasmonic acid. | leucine aminopeptidase a (lapa) is a late wound-response gene of tomato (solanum lycopersicum). to elucidate the role of lapa, transgenic plants that overexpressed or abolished lapa gene expression were used. the early wound-response gene rna levels were similar in wild-type and lap-silenced (lapa-si), -antisense (lapa-as), and -overexpressing (lapa-ox) plants. by contrast, late wound-response gene rna levels and protection against manduca sexta damage were influenced by lapa rna and protein lev ... | 2009 | 19376935 |
| deletions in the repertoire of pseudomonas syringae pv. tomato dc3000 type iii secretion effector genes reveal functional overlap among effectors. | the gamma-proteobacterial plant pathogen pseudomonas syringae pv. tomato dc3000 uses the type iii secretion system to inject ca. 28 avr/hop effector proteins into plants, which enables the bacterium to grow from low inoculum levels to produce bacterial speck symptoms in tomato, arabidopsis thaliana, and (when lacking hopq1-1) nicotiana benthamiana. the effectors are collectively essential but individually dispensable for the ability of the bacteria to defeat defenses, grow, and produce symptoms ... | 2009 | 19381254 |
| compromised stability of dna methylation and transposon immobilization in mosaic arabidopsis epigenomes. | transgenerational epigenetic inheritance has been defined by the study of relatively few loci. we examined a population of recombinant inbred lines with epigenetically mosaic chromosomes consisting of wild-type and cg methylation-depleted segments (epirils). surprisingly, transposons that were immobile in the parental lines displayed stochastic movement in 28% of the epirils. although analysis after eight generations of inbreeding, supported by genome-wide dna methylation profiling, identified r ... | 2009 | 19390088 |
| a novel pathogenicity gene is required in the rice blast fungus to suppress the basal defenses of the host. | for successful colonization and further reproduction in host plants, pathogens need to overcome the innate defenses of the plant. we demonstrate that a novel pathogenicity gene, des1, in magnaporthe oryzae regulates counter-defenses against host basal resistance. the des1 gene was identified by screening for pathogenicity-defective mutants in a t-dna insertional mutant library. bioinformatic analysis revealed that this gene encodes a serine-rich protein that has unknown biochemical properties, a ... | 2009 | 19390617 |
| accurate prediction of secreted substrates and identification of a conserved putative secretion signal for type iii secretion systems. | the type iii secretion system is an essential component for virulence in many gram-negative bacteria. though components of the secretion system apparatus are conserved, its substrates--effector proteins--are not. we have used a novel computational approach to confidently identify new secreted effectors by integrating protein sequence-based features, including evolutionary measures such as the pattern of homologs in a range of other organisms, g+c content, amino acid composition, and the n-termin ... | 2009 | 19390620 |
| sequence-based prediction of type iii secreted proteins. | the type iii secretion system (ttss) is a key mechanism for host cell interaction used by a variety of bacterial pathogens and symbionts of plants and animals including humans. the ttss represents a molecular syringe with which the bacteria deliver effector proteins directly into the host cell cytosol. despite the importance of the ttss for bacterial pathogenesis, recognition and targeting of type iii secreted proteins has up until now been poorly understood. several hypotheses are discussed, in ... | 2009 | 19390696 |
| antagonism between salicylic and abscisic acid reflects early host-pathogen conflict and moulds plant defence responses. | the importance of phytohormone balance is increasingly recognized as central to the outcome of plant-pathogen interactions. recently it has been demonstrated that abscisic acid signalling pathways are utilized by the bacterial phytopathogen pseudomonas syringae to promote pathogenesis. in this study, we examined the dynamics, inter-relationship and impact of three key acidic phytohormones, salicylic acid, abscisic acid and jasmonic acid, and the bacterial virulence factor, coronatine, during pro ... | 2009 | 19392690 |
| role of quorum sensing in sinorhizobium meliloti-alfalfa symbiosis. | the expr/sin quorum-sensing system of the gram-negative soil bacterium sinorhizobium meliloti plays an important role in the establishment of symbiosis with its host plant medicago sativa. a mutant unable to produce autoinducer signal molecules (sini) is deficient in its ability to invade the host, but paradoxically, a strain lacking the quorum-sensing transcriptional regulator expr is as efficient as the wild type. we compared the whole-genome expression profile of the wild-type strain with str ... | 2009 | 19395488 |
| chloroplast-derived vaccine antigens and biopharmaceuticals: expression, folding, assembly and functionality. | chloroplast genetic engineering offers several advantages, including high levels of transgene expression, transgene containment via maternal inheritance, and multi-gene expression in a single transformation event. oral delivery is facilitated by hyperexpression of vaccine antigens against cholera, tetanus, anthrax, plague, or canine parvovirus (4%-31% of total soluble protein, tsp) in transgenic chloroplasts (leaves) or non-green plastids (carrots, tomato) as well as the availability of antibiot ... | 2009 | 19401820 |
| phylogeny and virulence of naturally occurring type iii secretion system-deficient pectobacterium strains. | pectobacterium species are enterobacterial plant-pathogenic bacteria that cause soft rot disease in diverse plant species. previous epidemiological studies of pectobacterium species have suffered from an inability to identify most isolates to the species or subspecies level. we used three previously described dna-based methods, 16s-23s intergenic transcribed spacer pcr-restriction fragment length polymorphism analysis, multilocus sequence analysis (mlsa), and pulsed-field gel electrophoresis, to ... | 2009 | 19411432 |
| translocation of green fluorescent protein to cyanobacterial periplasm using ice nucleation protein. | the translocation of proteins to cyanobacterial cell envelope is made complex by the presence of a highly differentiated membrane system. to investigate the protein translocation in cyanobacterium synechococcus pcc 7942 using the truncated ice nucleation protein (inpnc) from pseudomonas syringae kctc 1832, the green fluorescent protein (gfp) was fused in frame to the carboxyl-terminus of inpnc. the fluorescence of gfp was found almost entirely as a halo in the outer regions of cells which appear ... | 2009 | 19412603 |
| priming of plant innate immunity by rhizobacteria and beta-aminobutyric acid: differences and similarities in regulation. | pseudomonas fluorescens wcs417r bacteria and beta-aminobutyric acid can induce disease resistance in arabidopsis, which is based on priming of defence. in this study, we examined the differences and similarities of wcs417r- and beta-aminobutyric acid-induced priming. both wcs417r and beta-aminobutyric acid prime for enhanced deposition of callose-rich papillae after infection by the oomycete hyaloperonospora arabidopsis. this priming is regulated by convergent pathways, which depend on phosphoin ... | 2009 | 19413686 |
| flg22 regulates the release of an ethylene response factor substrate from map kinase 6 in arabidopsis thaliana via ethylene signaling. | mitogen-activated protein kinase (mapk)-mediated responses are in part regulated by the repertoire of mapk substrates, which is still poorly elucidated in plants. here, the in vivo enzyme-substrate interaction of the arabidopsis thaliana map kinase, mpk6, with an ethylene response factor (erf104) is shown by fluorescence resonance energy transfer. the interaction was rapidly lost in response to flagellin-derived flg22 peptide. this complex disruption requires not only mpk6 activity, which also a ... | 2009 | 19416906 |
| arabidopsis harmless to ozone layer protein methylates a glucosinolate breakdown product and functions in resistance to pseudomonas syringae pv. maculicola. | almost all of the chlorine-containing gas emitted from natural sources is methyl chloride (ch(3)cl), which contributes to the destruction of the stratospheric ozone layer. tropical and subtropical plants emit substantial amounts of ch(3)cl. a gene involved in ch(3)cl emission from arabidopsis was previously identified and designated harmless to ozone layer (hereafter athol1) based on the mutant phenotype. our previous studies demonstrated that athol1 and its homologs, athol2 and athol3, have s-a ... | 2009 | 19419967 |
| the role of wrky transcription factors in plant immunity. | 2009 | 19420325 | |
| abscisic acid negatively regulates elicitor-induced synthesis of capsidiol in wild tobacco. | in the solanaceae, biotic and abiotic elicitors induce de novo synthesis of sesquiterpenoid stress metabolites known as phytoalexins. because plant hormones play critical roles in the induction of defense-responsive genes, we have explored the effect of abscisic acid (aba) on the synthesis of capsidiol, the major wild tobacco (nicotiana plumbaginifolia) sesquiterpenoid phytoalexin, using wild-type plants versus nonallelic mutants npaba2 and npaba1 that are deficient in aba synthesis. npaba2 and ... | 2009 | 19420326 |
| elucidation of a ph-folding switch in the pseudomonas syringae effector protein avrpto. | pathogenic bacteria have developed extraordinary strategies for invading host cells. the highly conserved type iii secretion system (t3ss) provides a regulated conduit between the bacterial and host cytoplasm for delivery of a specific set of bacterial effector proteins that serve to disrupt host signaling and metabolism for the benefit of the bacterium. remarkably, the inner diameter of the t3ss apparatus requires that effector proteins pass through in at least a partially unfolded form. avrpto ... | 2009 | 19423671 |
| innate immunity in plants: an arms race between pattern recognition receptors in plants and effectors in microbial pathogens. | for many years, research on a suite of plant defense responses that begin when plants are exposed to general microbial elicitors was underappreciated, for a good reason: there has been no critical experimental demonstration of their importance in mediating plant resistance during pathogen infection. today, these microbial elicitors are named pathogen- or microbe-associated molecular patterns (pamps or mamps) and the plant responses are known as pamp-triggered immunity (pti). recent studies provi ... | 2009 | 19423812 |
| terrific protein traffic: the mystery of effector protein delivery by filamentous plant pathogens. | many biotrophic fungal and oomycete plant pathogens deliver effector proteins directly into host cells during infection. recent advances are revealing the extensive effector repertoires of these pathogens and are beginning to shed light on how they manipulate host cells to establish a parasitic relationship. surprisingly, oomycete effectors seem to share a common uptake system with those from the human malaria pathogen. the current explosion of information is opening new research avenues in mole ... | 2009 | 19423815 |
| host inhibition of a bacterial virulence effector triggers immunity to infection. | plant pathogenic bacteria secrete effector proteins that attack the host signaling machinery to suppress immunity. effectors can be recognized by hosts leading to immunity. one such effector is avrptob of pseudomonas syringae, which degrades host protein kinases, such as tomato fen, through an e3 ligase domain. pto kinase, which is highly related to fen, recognizes avrptob in conjunction with the resistance protein prf. here we show that pto is resistant to avrptob-mediated degradation because i ... | 2009 | 19423826 |
| comparison of the transcriptomes of american chestnut (castanea dentata) and chinese chestnut (castanea mollissima) in response to the chestnut blight infection. | background1471-2229-9-51: american chestnut (castanea dentata) was devastated by an exotic pathogen in the beginning of the twentieth century. this chestnut blight is caused by cryphonectria parasitica, a fungus that infects stem tissues and kills the trees by girdling them. because of the great economic and ecological value of this species, significant efforts have been made over the century to combat this disease, but it wasn't until recently that a focused genomics approach was initiated. pri ... | 2009 | 19426529 |
| response to excess copper in the hyperthermophile sulfolobus solfataricus strain 98/2. | copper is an essential micronutrient, but toxic in excess. sulfolobus solfataricus cells have the ability to adapt to fluctuations of copper levels in their external environment. to better understand the molecular mechanism behind the organismal response to copper, the expression of the cluster of genes coprta, which encodes the copper-responsive transcriptional regulator copr, the copper-binding protein copt, and copa, has been investigated and the whole operon has been shown to be cotranscribe ... | 2009 | 19427833 |
| importance of trme for growth of the psychrophile pseudomonas syringae at low temperatures. | transposon mutagenesis of pseudomonas syringae lz4w, a psychrophilic bacterium capable of growing at temperatures between 2 and 30 degrees c, yielded 30 cold-sensitive mutants, and csm1, one of these cold-sensitive mutants, was characterized. growth of csm1 was retarded when it was cultured at 4 degrees c but not when it was cultured at 22 degrees c and 28 degrees c compared to the growth of wild-type cells, indicating that csm1 is a cold-sensitive mutant of p. syringae lz4w. the mutated gene in ... | 2009 | 19429554 |
| genome sequence of azotobacter vinelandii, an obligate aerobe specialized to support diverse anaerobic metabolic processes. | azotobacter vinelandii is a soil bacterium related to the pseudomonas genus that fixes nitrogen under aerobic conditions while simultaneously protecting nitrogenase from oxygen damage. in response to carbon availability, this organism undergoes a simple differentiation process to form cysts that are resistant to drought and other physical and chemical agents. here we report the complete genome sequence of a. vinelandii dj, which has a single circular genome of 5,365,318 bp. in order to reconcile ... | 2009 | 19429624 |
| characterization of vitis vinifera npr1 homologs involved in the regulation of pathogenesis-related gene expression. | grapevine protection against diseases needs alternative strategies to the use of phytochemicals, implying a thorough knowledge of innate defense mechanisms. however, signalling pathways and regulatory elements leading to induction of defense responses have yet to be characterized in this species. in order to study defense response signalling to pathogens in vitis vinifera, we took advantage of its recently completed genome sequence to characterize two putative orthologs of npr1, a key player in ... | 2009 | 19432948 |
| genomic and genetic analyses of diversity and plant interactions of pseudomonas fluorescens. | pseudomonas fluorescens are common soil bacteria that can improve plant health through nutrient cycling, pathogen antagonism and induction of plant defenses. the genome sequences of strains sbw25 and pf0-1 were determined and compared to each other and with p. fluorescens pf-5. a functional genomic in vivo expression technology (ivet) screen provided insight into genes used by p. fluorescens in its natural environment and an improved understanding of the ecological significance of diversity with ... | 2009 | 19432983 |
| the ngatha genes direct style development in the arabidopsis gynoecium. | the gynoecium is the most complex floral organ, designed to protect the ovules and ensure their fertilization. correct patterning and tissue specification in the developing gynoecium involves the concerted action of a host of genetic factors. in addition, apical-basal patterning into different domains, stigma and style, ovary and gynophore, appears to depend on the establishment and maintenance of asymmetric auxin distribution, with an auxin maximum at the apex. here, we show that a small subfam ... | 2009 | 19435937 |
| evidence for a role of gibberellins in salicylic acid-modulated early plant responses to abiotic stress in arabidopsis seeds. | exogenous application of gibberellic acid (ga(3)) was able to reverse the inhibitory effect of salt, oxidative, and heat stresses in the germination and seedling establishment of arabidopsis (arabidopsis thaliana), this effect being accompanied by an increase in salicylic acid (sa) levels, a hormone that in recent years has been implicated in plant responses to abiotic stress. furthermore, this treatment induced an increase in the expression levels of the isochorismate synthase1 and nonexpressor ... | 2009 | 19439570 |
| limited transcriptional responses of rickettsia rickettsii exposed to environmental stimuli. | rickettsiae are strict obligate intracellular pathogens that alternate between arthropod and mammalian hosts in a zoonotic cycle. typically, pathogenic bacteria that cycle between environmental sources and mammalian hosts adapt to the respective environments by coordinately regulating gene expression such that genes essential for survival and virulence are expressed only upon infection of mammals. temperature is a common environmental signal for upregulation of virulence gene expression although ... | 2009 | 19440298 |
| crystal structures of cif from bacterial pathogens photorhabdus luminescens and burkholderia pseudomallei. | a pre-requisite for bacterial pathogenesis is the successful interaction of a pathogen with a host. one mechanism used by a broad range of gram negative bacterial pathogens is to deliver effector proteins directly into host cells through a dedicated type iii secretion system where they modulate host cell function. the cycle inhibiting factor (cif) family of effector proteins, identified in a growing number of pathogens that harbour functional type iii secretion systems and have a wide host range ... | 2009 | 19440549 |
| the xanthomonas campestris pv. vesicatoria type iii effector protein xopj inhibits protein secretion: evidence for interference with cell wall-associated defense responses. | the phytopathogenic bacterium xanthomonas campestris pv. vesicatoria uses the type iii secretion system (t3ss) to inject effector proteins into cells of its solanaceous host plants. it is generally assumed that these effectors manipulate host pathways to favor bacterial replication and survival. however, the molecular mechanisms by which type iii effectors suppress host defense responses are far from being understood. based on sequence similarity, xanthomonas outer protein j (xopj) is a member o ... | 2009 | 19445590 |
| multiple activities of the plant pathogen type iii effector proteins wtse and avre require wxxxe motifs. | the broadly conserved avre-family of type iii effectors from gram-negative plant-pathogenic bacteria includes important virulence factors, yet little is known about the mechanisms by which these effectors function inside plant cells to promote disease. we have identified two conserved motifs in avre-family effectors: a wxxxe motif and a putative c-terminal endoplasmic reticulum membrane retention/retrieval signal (ermrs). the wxxxe and ermrs motifs are both required for the virulence activities ... | 2009 | 19445595 |
| kinetic buffering of cross talk between bacterial two-component sensors. | two-component systems are a class of sensors that enable bacteria to respond to environmental and cell-state signals. the canonical system consists of a membrane-bound sensor histidine kinase that autophosphorylates in response to a signal and transfers the phosphate to an intracellular response regulator. bacteria typically have dozens of two-component systems. the key questions are whether these systems are linear and, if they are, how cross talk between systems is buffered. in this work, we s ... | 2009 | 19445950 |
| diversity and functional analysis of luxr-type transcriptional regulators of cyclic lipopeptide biosynthesis in pseudomonas fluorescens. | cyclic lipopeptides (clps) are produced by many pseudomonas species and have several biological functions, including a role in surface motility, biofilm formation, virulence, and antimicrobial activity. this study focused on the diversity and role of luxr-type transcriptional regulators in clp biosynthesis in pseudomonas species and, specifically, viscosin production by pseudomonas fluorescens strain sbw25. phylogenetic analyses showed that clp biosynthesis genes in pseudomonas strains are flank ... | 2009 | 19447950 |
| microbial siderophores exert a subtle role in arabidopsis during infection by manipulating the immune response and the iron status. | siderophores (ferric ion chelators) are secreted by organisms in response to iron deficiency. the pathogenic enterobacterium erwinia chrysanthemi produces two siderophores, achromobactin and chrysobactin (cb), which are required for systemic dissemination in host plants. previous studies have shown that cb is produced in planta and can trigger the up-regulation of the plant ferritin gene atfer1. to further investigate the function of cb during pathogenesis, we analyzed its effect in arabidopsis ... | 2009 | 19448037 |
| identification of chlorogenic acid as a resistance factor for thrips in chrysanthemum. | western flower thrips (frankliniella occidentalis) has become a key insect pest of agricultural and horticultural crops worldwide. little is known about host plant resistance to thrips. in this study, we investigated thrips resistance in chrysanthemum (dendranthema grandiflora). we identified thrips-resistant chrysanthemums applying bioassays. subsequently, nuclear magnetic resonance (nmr)-based metabolomics was applied to compare the metabolome of thrips-resistant and -susceptible chrysanthemum ... | 2009 | 19448039 |
| functional redundancy in the arabidopsis cathepsin b gene family contributes to basal defence, the hypersensitive response and senescence. | cysteine proteases are required for programmed cell death (pcd) in animals. recent work in nicotiana benthamiana has implicated cathepsin b-like cysteine proteases in the hypersensitive response (hr) in plants, a form of pcd involved in disease resistance. here, we investigate the function and regulation of cathepsin b (cathb) genes in plant defence, and in both pathogen-inducible and developmental forms of pcd. single, double and triple knockout mutants were isolated for the three arabidopsis t ... | 2009 | 19453434 |
| the role of respiratory burst oxidase homologues in elicitor-induced stomatal closure and hypersensitive response in nicotiana benthamiana. | active oxygen species (aos) are central components of the defence reactions of plants against pathogens. plant respiratory burst oxidase homologues (rboh) of gp91(phox), a plasma membrane protein of the neutrophil nicotinamide adenine dinucleotide phosphate (nadph) oxidase, play a prominent role in aos production. the role of two rboh from nicotiana benthamiana, nbrboha and nbrbohb that encode plant nadph oxidase in the process of elicitor-induced stomatal closure and hypersensitive cell death i ... | 2009 | 19454596 |
| understanding the regulation of aspartate metabolism using a model based on measured kinetic parameters. | the aspartate-derived amino-acid pathway from plants is well suited for analysing the function of the allosteric network of interactions in branched pathways. for this purpose, a detailed kinetic model of the system in the plant model arabidopsis was constructed on the basis of in vitro kinetic measurements. the data, assembled into a mathematical model, reproduce in vivo measurements and also provide non-intuitive predictions. a crucial result is the identification of allosteric interactions wh ... | 2009 | 19455135 |
| positive selection in avrp4 avirulence gene homologues across the genus melampsora. | pathogen genes involved in interactions with their plant hosts are expected to evolve under positive darwinian selection or balancing selection. in this study a single copy avirulence gene, avrp4, in the plant pathogen melampsora lini, was used to investigate the evolution of such a gene across species. partial translation elongation factor 1-alpha sequences were obtained to establish phylogenetic relationships among the melampsora species. we amplified avrp4 homologues from species pathogenic o ... | 2009 | 19457888 |
| characterization of arabidopsis 6-phosphogluconolactonase t-dna insertion mutants reveals an essential role for the oxidative section of the plastidic pentose phosphate pathway in plant growth and development. | arabidopsis pgl1, pgl2, pgl4 and pgl5 are predicted to encode cytosolic isoforms of 6-phosphogluconolactonase (6pgl), whereas pgl3 is predicted to encode a 6pgl that has been shown to localize in both plastids and peroxisomes. therefore, 6pgl may exist in the cytosol, plastids and peroxisomes. however, the function of 6pgl in these three subcellular locations has not been well defined. here we show that pgl3 is essential, whereas pgl1, pgl2 and pgl5 are individually dispensable for plant growth ... | 2009 | 19457984 |
| type iii protein secretion in plant pathogenic bacteria. | 2009 | 19458111 | |
| ripening-regulated susceptibility of tomato fruit to botrytis cinerea requires nor but not rin or ethylene. | fruit ripening is a developmental process that is associated with increased susceptibility to the necrotrophic pathogen botrytis cinerea. histochemical observations demonstrate that unripe tomato (solanum lycopersicum) fruit activate pathogen defense responses, but these responses are attenuated in ripe fruit infected by b. cinerea. tomato fruit ripening is regulated independently and cooperatively by ethylene and transcription factors, including non-ripening (nor) and ripening-inhibitor (rin). ... | 2009 | 19465579 |
| transcriptome analysis of a bacterially induced basal and hypersensitive response of medicago truncatula. | research using the well-studied model legume medicago truncatula has largely focused on rhizobium symbiosis, while little information is currently available for this species on pathogen-induced transcriptome changes. we have performed a transcriptome analysis of this species with the objective of studying the basal (br, no visible symptoms) and hypersensitive response (hr, plant cell death) in its leaves at 6 and at 24 h after infection by hr-negative (hrcc mutant) and hr-inducing pseudomonas sy ... | 2009 | 19466566 |
| homeopathic treatment of arabidopsis thaliana plants infected with pseudomonas syringae. | homeopathic basic research is still in the screening phase to identify promising model systems that are adapted to the needs and peculiarities of homeopathic medicine and pharmacy. we investigated the potential of a common plant-pathogen system, arabidopsis thaliana infected with the virulent bacteria pseudomonas syringae, regarding its response towards a homeopathic treatment. a. thaliana plants were treated with homeopathic preparations before and after infection. outcome measure was the numbe ... | 2009 | 19468651 |
| systems level analysis of two-component signal transduction systems in erwinia amylovora: role in virulence, regulation of amylovoran biosynthesis and swarming motility. | two-component signal transduction systems (tcsts), consisting of a histidine kinase (hk) and a response regulator (rr), represent a major paradigm for signal transduction in prokaryotes. tcsts play critical roles in sensing and responding to environmental conditions, and in bacterial pathogenesis. most tcsts in erwinia amylovora have either not been identified or have not yet been studied. | 2009 | 19470164 |
| evidence for a positive regulatory role of strawberry (fragaria x ananassa) fa wrky1 and arabidopsis at wrky75 proteins in resistance. | knowledge of the molecular basis of plant resistance to pathogens in species other than arabidopsis is limited. the function of fa wrky1, the first wrky gene isolated from strawberry (fragaria x ananassa), an important agronomical fruit crop, has been investigated here. fa wrky1 encodes a iic wrky transcription factor and is up-regulated in strawberry following colletotrichum acutatum infection, treatments with elicitors, and wounding. its arabidopsis sequence homologue, at wrky75, has been desc ... | 2009 | 19470657 |
| plant-pathogen interactions and elevated co2: morphological changes in favour of pathogens. | crop losses caused by pests and weeds have been estimated at 42% worldwide, with plant pathogens responsible for almost $10 billion worth of damage in the usa in 1994 alone. elevated carbon dioxide [eco(2)] and associated climate change have the potential to accelerate plant pathogen evolution, which may, in turn, affect virulence. plant-pathogen interactions under increasing co(2) concentrations have the potential to disrupt both agricultural and natural systems severely, yet the lack of experi ... | 2009 | 19470658 |
| the fractionated orthology of bs2 and rx/gpa2 supports shared synteny of disease resistance in the solanaceae. | comparative genomics provides a powerful tool for the identification of genes that encode traits shared between crop plants and model organisms. pathogen resistance conferred by plant r genes of the nucleotide-binding-leucine-rich-repeat (nb-lrr) class is one such trait with great agricultural importance that occupies a critical position in understanding fundamental processes of pathogen detection and coevolution. the proposed rapid rearrangement of r genes in genome evolution would make compara ... | 2009 | 19474202 |
| ph-, temperature- and ion-dependent oligomerization of sulfolobus solfataricus recombinant amidase: a study with site-specific mutants. | recombinant amidase from sulfolobus solfataricus occurred as a dimer of 110 kda comprising identical subunits. only dimers were present at phs above 7.0, but with decreasing ph, dimers associated into octamers, with complete oligomerization occurring at ph 3.0. oligomerization showed reversible temperature-dependence, with octamer formation increasing with temperature from 36 degrees c to between 70 and 80 degrees c. increasing salt concentrations, favored dissociation of the octamers. among the ... | 2009 | 19478917 |
| analysis of achromobactin biosynthesis by pseudomonas syringae pv. syringae b728a. | pseudomonas syringae pv. syringae b728a is known to produce the siderophore pyoverdine under iron-limited conditions. it has also been proposed that this pathovar has the ability to produce a second siderophore, achromobactin. here we present genetic and biochemical evidence supporting the hypothesis that p. syringae pv. syringae b728a produces both of these siderophores. we show that strains unable to synthesize either pyoverdine or achromobactin are unable to grow under iron-limiting condition ... | 2009 | 19482931 |
| genome assembly reborn: recent computational challenges. | research into genome assembly algorithms has experienced a resurgence due to new challenges created by the development of next generation sequencing technologies. several genome assemblers have been published in recent years specifically targeted at the new sequence data; however, the ever-changing technological landscape leads to the need for continued research. in addition, the low cost of next generation sequencing data has led to an increased use of sequencing in new settings. for example, t ... | 2009 | 19482960 |
| comparative genomics-guided loop-mediated isothermal amplification for characterization of pseudomonas syringae pv. phaseolicola. | to design and evaluate a loop-mediated isothermal amplification (lamp) protocol by combining comparative genomics and bioinformatics for characterization of pseudomonas syringae pv. phaseolicola (psp), the causal agent of halo blight disease of bean (phaseolus vulgaris l.). | 2009 | 19486391 |
| levels of selected trace elements, phytohormones, and sugars in pseudomonas-infected lycopersicum esculantum mill plants. | the present study investigated the levels of trace elements (zn, cu, fe, pb, and cd), major elements (ca and k), phytohormones (trans-zeatin [t-z] and gibberellic acid [ga]), and sugars (sucrose and glucose) following inoculation with pseudomonas syringae pv. tomato strain. the results of the trace elements analysis showed that fe (in the first, fourth, eighth, and tenth study days), cd (in the fourth, eighth, and tenth study days), cu (in the fourth and eighth study days), and zn (in the eighth ... | 2010 | 19488684 |
| biosynthesis of phosphonic and phosphinic acid natural products. | natural products containing carbon-phosphorus bonds (phosphonic and phosphinic acids) have found widespread use in medicine and agriculture. recent years have seen a renewed interest in the biochemistry and biology of these compounds with the cloning of the biosynthetic gene clusters for several family members. this review discusses the commonalities and differences in the molecular logic that lie behind the biosynthesis of these compounds. the current knowledge regarding the metabolic pathways ... | 2009 | 19489722 |
| structural basis for the erythro-stereospecificity of the l-arginine oxygenase vioc in viomycin biosynthesis. | the nonheme iron oxygenase vioc from streptomyces vinaceus catalyzes fe(ii)-dependent and alpha-ketoglutarate-dependent cbeta-hydroxylation of l-arginine during the biosynthesis of the tuberactinomycin antibiotic viomycin. crystal structures of vioc were determined in complexes with the cofactor fe(ii), the substrate l-arginine, the product (2s,3s)-hydroxyarginine and the coproduct succinate at 1.1-1.3 a resolution. the overall structure reveals a beta-helix core fold with two additional helical ... | 2009 | 19490124 |
| proteasome-mediated turnover of the transcription coactivator npr1 plays dual roles in regulating plant immunity. | systemic acquired resistance (sar) is a broad-spectrum plant immune response involving profound transcriptional changes that are regulated by the coactivator npr1. nuclear translocation of npr1 is a critical regulatory step, but how the protein is regulated in the nucleus is unknown. here, we show that turnover of nuclear npr1 protein plays an important role in modulating transcription of its target genes. in the absence of pathogen challenge, npr1 is continuously cleared from the nucleus by the ... | 2009 | 19490895 |
| identification and expression analysis of wrky transcription factor genes in canola (brassica napus l.) in response to fungal pathogens and hormone treatments. | members of plant wrky transcription factor families are widely implicated in defense responses and various other physiological processes. for canola (brassica napus l.), no wrky genes have been described in detail. because of the economic importance of this crop, and its evolutionary relationship to arabidopsis thaliana, we sought to characterize a subset of canola wrky genes in the context of pathogen and hormone responses. | 2009 | 19493335 |
| comprehensive comparative-genomic analysis of type 2 toxin-antitoxin systems and related mobile stress response systems in prokaryotes. | the prokaryotic toxin-antitoxin systems (tas, also referred to as ta loci) are widespread, mobile two-gene modules that can be viewed as selfish genetic elements because they evolved mechanisms to become addictive for replicons and cells in which they reside, but also possess "normal" cellular functions in various forms of stress response and management of prokaryotic population. several distinct tas of type 1, where the toxin is a protein and the antitoxin is an antisense rna, and numerous, unr ... | 2009 | 19493340 |
| cre-lox univector acceptor vectors for functional screening in protoplasts: analysis of arabidopsis donor cdnas encoding abscisic acid insensitive1-like protein phosphatases. | the 14,200 available full length arabidopsis thaliana cdnas in the universal plasmid system (ups) donor vector puni51 should be applied broadly and efficiently to leverage a "functional map-space" of homologous plant genes. we have engineered cre-lox ups host acceptor vectors (pcr701- 705) with n-terminal epitope tags in frame with the loxh site and downstream from the maize ubiquitin promoter for use in transient protoplast expression assays and particle bombardment transformation of monocots. ... | 2009 | 19499346 |
| characterization of airborne microbial communities at a high-elevation site and their potential to act as atmospheric ice nuclei. | bacteria and fungi are ubiquitous in the atmosphere. the diversity and abundance of airborne microbes may be strongly influenced by atmospheric conditions or even influence atmospheric conditions themselves by acting as ice nucleators. however, few comprehensive studies have described the diversity and dynamics of airborne bacteria and fungi based on culture-independent techniques. we document atmospheric microbial abundance, community composition, and ice nucleation at a high-elevation site in ... | 2009 | 19502432 |