Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| quercetin-induced h(2)o(2) mediates the pathogen resistance against pseudomonas syringae pv. tomato dc3000 in arabidopsis thaliana. | quercetin is a potent antioxidant and has been extensively used as a therapy intervention to prevent age-associated diseases. however, emerging studies showed it can also act as a prooxidant and induce h(2)o(2) under certain conditions. in the current study, our results showed that quercetin contributed to the pathogen resistance in arabidopsis thaliana (arabidopsis) in response to the infection of virulent strain pseudomonas syringae pv. tomato dc3000 (pst). various defense responses, such as h ... | 2010 | 20434432 |
| commonalities and differences in regulation of n-acyl homoserine lactone quorum sensing in the beneficial plant-associated burkholderia species cluster. | the genus burkholderia includes over 60 species isolated from a wide range of environmental niches and can be tentatively divided into two major species clusters. the first cluster includes pathogens such as burkholderia glumae, b. pseudomallei, and b. mallei and 17 well-studied species of the burkholderia cepacia complex. the other recently established cluster comprises at least 29 nonpathogenic species, which in most cases have been found to be associated with plants. it was previously establi ... | 2010 | 20435760 |
| domain cross-talk during effector binding to the multidrug binding ttgr regulator. | a major mechanism of antibiotic resistance in bacteria is the active extrusion of toxic compounds through membrane-bound efflux pumps. the ttgr protein represses transcription of ttgabc, a key efflux pump in pseudomonas putida dot-t1e capable of extruding antibiotics, solvents, and flavonoids. ttgr contains two distinct and overlapping ligand binding sites, one is broad and contains mainly hydrophobic residues, whereas the second is deep and contains polar residues. mutants in the ligand binding ... | 2010 | 20435893 |
| jasmonate and phytochrome a signaling in arabidopsis wound and shade responses are integrated through jaz1 stability. | jasmonate (ja) activates plant defense, promotes pollen maturation, and suppresses plant growth. an emerging theme in ja biology is its involvement in light responses; here, we examine the interdependence of the ja- and light-signaling pathways in arabidopsis thaliana. we demonstrate that mutants deficient in ja biosynthesis and signaling are deficient in a subset of high irradiance responses in far-red (fr) light. these mutants display exaggerated shade responses to low, but not high, r/fr rati ... | 2010 | 20435902 |
| argonaute quenching and global changes in dicer homeostasis caused by a pathogen-encoded gw repeat protein. | in plants and invertebrates, viral-derived sirnas processed by the rnaseiii dicer guide argonaute (ago) proteins as part of antiviral rna-induced silencing complexes (risc). as a counterdefense, viruses produce suppressor proteins (vsrs) that inhibit the host silencing machinery, but their mechanisms of action and cellular targets remain largely unknown. here, we show that the turnip crinckle virus (tcv) capsid, the p38 protein, acts as a homodimer, or multiples thereof, to mimic host-encoded gl ... | 2010 | 20439431 |
| regulation of the expression of plant resistance gene snc1 by a protein with a conserved bat2 domain. | plant resistance (r) genes encode immune receptors that recognize pathogens and activate defense responses. because of fitness costs associated with maintaining r protein-mediated resistance, expression levels of r genes have to be tightly regulated. however, mechanisms on how r-gene expression is regulated are poorly understood. here we show that modifier of snc1, 1 (mos1) regulates the expression of suppressor of npr1-1, constitutive1 (snc1), which encodes a toll/interleukin receptor-nucleotid ... | 2010 | 20439546 |
| a domain swap approach reveals a role of the plant wall-associated kinase 1 (wak1) as a receptor of oligogalacturonides. | oligogalacturonides (ogs) released from the plant cell wall are active both as damage-associated molecular patterns (damps) for the activation of the plant immune response and regulators of plant growth and development. members of the wall-associated kinase (wak) family are candidate receptors of ogs, due to their ability to bind in vitro these oligosaccharides. because lethality and redundancy have hampered the study of waks by reverse genetics, we have adopted a chimeric receptor approach to e ... | 2010 | 20439716 |
| changes in external ph rapidly alter plant gene expression and modulate auxin and elicitor responses. | ph is a highly variable environmental factor for the root, and plant cells can modify apoplastic ph for nutrient acquisition and in response to extracellular signals. nevertheless, surprisingly few effects of external ph on plant gene expression have been reported. we have used microarrays to investigate whether external ph affects global gene expression. in arabidopsis thaliana roots, 881 genes displayed at least twofold changes in transcript abundance 8 h after shifting medium ph from 6.0 to 4 ... | 2010 | 20444216 |
| a role for beta-sitosterol to stigmasterol conversion in plant-pathogen interactions. | upon inoculation with pathogenic microbes, plants induce an array of metabolic changes that potentially contribute to induced resistance or even enhance susceptibility. when analysing leaf lipid composition during the arabidopsis thaliana-pseudomonas syringae interaction, we found that accumulation of the phytosterol stigmasterol is a significant plant metabolic process that occurs upon bacterial leaf infection. stigmasterol is synthesized from beta-sitosterol by the cytochrome p450 cyp710a1 via ... | 2010 | 20444228 |
| a new shuttle vector for gene expression in biopolymer-producing ralstonia eutropha. | ralstonia eutropha (formerly alcaligenes eutrophus) is a fascinating microorganism with a great scientific importance and an immense commercial potential. a new genetic transformation system for the organism would greatly facilitate the biological study and molecular engineering of this organism. we report here a versatile gene expression method for the genetic engineering of r. eutropha. this method, based on a simplified electroporation protocol, uses a recombinant plasmid, pbs29-p2, containin ... | 2010 | 20447426 |
| deciphering the assembly of the yersinia type iii secretion injectisome. | the assembly of the yersinia enterocolitica type iii secretion injectisome was investigated by grafting fluorescent proteins onto several components, yscc (outer-membrane (om) ring), yscd (forms the inner-membrane (im) ring together with yscj), yscn (atpase), and yscq (putative c ring). the recombinant injectisomes were functional and appeared as fluorescent spots at the cell periphery. epistasis experiments with the hybrid alleles in an array of injectisome mutants revealed a novel outside-in a ... | 2010 | 20453832 |
| ligand binding and crystal structures of the substrate-binding domain of the abc transporter opua. | the abc transporter opua from lactococcus lactis transports glycine betaine upon activation by threshold values of ionic strength. in this study, the ligand binding characteristics of purified opua in a detergent-solubilized state and of its substrate-binding domain produced as soluble protein (opuac) was characterized. | 2010 | 20454456 |
| genetic engineering of stenotrophomonas strain yc-1 to possess a broader substrate range for organophosphates. | in this work, stenotrophomonas sp. strain yc-1, a native soil bacterium that produces methyl parathion hydrolase (mph), was genetically engineered to possess a broader substrate range for organophosphates (ops). a surface anchor system derived from the truncated ice nucleation protein (inpnc) from pseudomonas syringae was used to target organophosphorus hydrolase (oph) onto the cell surface of strain yc-1, reducing the potential substrate uptake limitation. the surface localization of inpnc-oph ... | 2010 | 20455565 |
| distinct and dynamic auxin activities during reproductive development. | flowering plants have evolved sophisticated and complicated reproductive structures to ensure optimal conditions for the next generation. successful reproduction relies on careful timing and coordination of tissue development, which requires constant communication between these tissues. work on flower and fruit development over the last decade places the phytohormone auxin in a key role as a master of patterning and tissue specification of reproductive organs. although many questions still remai ... | 2009 | 20457563 |
| a prominent role of the flagellin receptor flagellin-sensing2 in mediating stomatal response to pseudomonas syringae pv tomato dc3000 in arabidopsis. | the flagellin-sensing2 (fls2) receptor kinase recognizes bacterial flagellin and initiates a battery of downstream defense responses to reduce bacterial invasion through stomata in the epidermis and bacterial multiplication in the apoplast of infected plants. recent studies have shown that during pseudomonas syringae pv tomato (pst) dc3000 infection of arabidopsis (arabidopsis thaliana), fls2-mediated immunity is actively suppressed by effector proteins (such as avrpto and avrptob) secreted thro ... | 2010 | 20457804 |
| phytophthora infestans effector avr3a is essential for virulence and manipulates plant immunity by stabilizing host e3 ligase cmpg1. | fungal and oomycete plant pathogens translocate effector proteins into host cells to establish infection. however, virulence targets and modes of action of their effectors are unknown. effector avr3a from potato blight pathogen phytophthora infestans is translocated into host cells and occurs in two forms: avr3a(ki), which is detected by potato resistance protein r3a, strongly suppresses infestin 1 (inf1)-triggered cell death (icd), whereas avr3a(em), which evades recognition by r3a, weakly supp ... | 2010 | 20457921 |
| components of the pseudomonas syringae type iii secretion system can suppress and may elicit plant innate immunity. | the type iii secretion system (t3ss) of pseudomonas syringae translocates into plant cells multiple effectors that suppress pathogen-associated molecular pattern (pamp)-triggered immunity (pti). p. syringae pv. tomato dc3000 no longer delivers the t3ss translocation reporter avrpto-cya in nicotiana benthamiana leaf tissue in which pti was induced by prior inoculation with p. fluorescens(pln18). cosmid pln18 expresses the t3ss system of p. syringae pv. syringae 61 but lacks the hopa1(psy61) effec ... | 2010 | 20459312 |
| salicylate-mediated interactions between pathogens and herbivores. | plants employ hormone-mediated signaling pathways to defend against pathogens and insects. we tested predictions about the relative effect of jasmonate and salicylate pathways and how they mediate interactions between pathogens and herbivores. we employed two pathogens of tomato, pseudomonas syringae (pst) and tobacco mosaic virus (tmv), that are known to elicit distinct components of the two pathways, and we address the consequences of their induction for resistance in wild-type and salicylate- ... | 2010 | 20462121 |
| massively parallel pyrosequencing-based transcriptome analyses of small brown planthopper (laodelphax striatellus), a vector insect transmitting rice stripe virus (rsv). | the small brown planthopper (laodelphax striatellus) is an important agricultural pest that not only damages rice plants by sap-sucking, but also acts as a vector that transmits rice stripe virus (rsv), which can cause even more serious yield loss. despite being a model organism for studying entomology, population biology, plant protection, molecular interactions among plants, viruses and insects, only a few genomic sequences are available for this species. to investigate its transcriptome and d ... | 2010 | 20462456 |
| the t=1 capsid protein of penicillium chrysogenum virus is formed by a repeated helix-rich core indicative of gene duplication. | penicillium chrysogenum virus (pcv), a member of the chrysoviridae family, is a double-stranded rna (dsrna) fungal virus with a multipartite genome, with each rna molecule encapsidated in a separate particle. chrysoviruses lack an extracellular route and are transmitted during sporogenesis and cell fusion. the pcv capsid, based on a t=1 lattice containing 60 subunits of the 982-amino-acid capsid protein, remains structurally undisturbed throughout the viral cycle, participates in genome metaboli ... | 2010 | 20463071 |
| variation of herbivore-induced volatile terpenes among arabidopsis ecotypes depends on allelic differences and subcellular targeting of two terpene synthases, tps02 and tps03. | when attacked by insects, plants release mixtures of volatile compounds that are beneficial for direct or indirect defense. natural variation of volatile emissions frequently occurs between and within plant species, but knowledge of the underlying molecular mechanisms is limited. we investigated intraspecific differences of volatile emissions induced from rosette leaves of 27 accessions of arabidopsis (arabidopsis thaliana) upon treatment with coronalon, a jasmonate mimic eliciting responses sim ... | 2010 | 20463089 |
| surface display of heme- and diflavin-containing cytochrome p450 bm3 in escherichia coli: a whole cell biocatalyst for oxidation. | cytochrome p450 enzymes (p450s) are involved in the synthesis of a wide variety of valuable products and in the degradation of numerous toxic compounds. the p450 bm3 (cyp102a1) from bacillus megaterium was the first p450 discovered to be fused to its redox partner, a mammalian-like diflavin reductase. here, we report the development of a whole cell biocatalyst using ice-nucleation protein (inp) from pseudomonas syringae to display a heme- and diflavin-containing oxidoreductase, p450 bm3 (a singl ... | 2010 | 20467243 |
| elevating optimal human nutrition to a central goal of plant breeding and production of plant-based foods. | high-yielding cereals and other staples have produced adequate calories to ward off starvation for much of the world over several decades. however, deficiencies in certain amino acids, minerals, vitamins and fatty acids in staple crops, and animal diets derived from them, have aggravated the problem of malnutrition and the increasing incidence of certain chronic diseases in nominally well-nourished people (the so-called diseases of civilization). enhanced global nutrition has great potential to ... | 2009 | 20467463 |
| a microarray for screening the variability of 16s-23s rrna internal transcribed spacer in pseudomonas syringae. | the 16s-23s ribosomal internal transcribed spacer (its1) is often used as a subspecies or strain-specific molecular marker for various kinds of bacteria. however, the presence of different copies of its1 within a single genome has been reported. such mosaicism may influence correct typing of many bacteria and therefore knowledge about exact configuration of this region in a particular genome is essential. in order to screen the variability of its1 among and within pseudomonas syringae genomes, a ... | 2010 | 20470837 |
| novel functions of stomatal cytokinesis-defective 1 (scd1) in innate immune responses against bacteria. | eukaryotes employ complex immune mechanisms for protection against microbial pathogens. here, we identified scd1 (stomatal cytokinesis-defective 1), previously implicated in growth and development through its role in cytokinesis and polarized cell expansion (falbel, t. g., koch, l. m., nadeau, j. a., segui-simarro, j. m., sack, f. d., and bednarek, s. y. (2003) development 130, 4011-4024) as a novel component of innate immunity. in arabidopsis, scd1 is a unique gene encoding for the only protein ... | 2010 | 20472560 |
| the protein-dna contacts in rutr•carab operator complexes. | pyrimidine-specific regulation of the upstream carp1 promoter of the carbamoylphosphate synthase operon of escherichia coli requires numerous trans-acting factors: the allosteric transcription regulator rutr, the nucleoid-associated protein integration host factor, and the trigger enzymes aminopeptidase a and pyrh (ump-kinase). rutr, a tetr family member, binds far upstream of carp1. here, we establish a high-resolution contact map of rutr•carp1 complexes for backbone and base-specific contacts, ... | 2010 | 20472642 |
| sensor kinases rets and lads regulate pseudomonas syringae type vi secretion and virulence factors. | pseudomonas syringae pv. syringae b728a is a resident on leaves of common bean, where it utilizes several well-studied virulence factors, including secreted effectors and toxins, to develop a pathogenic interaction with its host. the b728a genome was recently sequenced, revealing the presence of 1,297 genes with unknown function. this study demonstrates that a 29.9-kb cluster of genes in the b728a genome shares homology to the novel type vi secretion system (t6ss) locus recently described for ot ... | 2010 | 20472799 |
| crystal structure of the pspto-psp protein from pseudomonas syringae pv. tomato str. dc3000 in complex with d-glucose. | the perchloric acid-soluble protein (psp) is an endoribonuclease and on the basis of sequence similarity has been assigned to the yjgf/yer057c/uk114 family. these family members are ubiquitous and highly conserved in evolution, and participate in regulating basic cellular metabolism. here we present the 2.1a crystal structure of the psp protein from pseudomonas syringae pv. tomato str. dc3000 (pspto-psp), in complex with d-glucose. the quaternary structure of pspto-psp is a homologous trimer. gl ... | 2010 | 20478270 |
| competition between phytophthora infestans effectors leads to increased aggressiveness on plants containing broad-spectrum late blight resistance. | the destructive plant disease potato late blight is caused by the oomycete pathogen phytophthora infestans (mont.) de bary. this disease has remained particularly problematic despite intensive breeding efforts to integrate resistance into cultivated potato, largely because of the pathogen's ability to quickly evolve to overcome major resistance genes. the rb gene, identified in the wild potato species s. bulbocastanum, encodes a protein that confers broad-spectrum resistance to most p. infestans ... | 2010 | 20479869 |
| nb-lrr proteins: pairs, pieces, perception, partners, and pathways. | in plants, many of the innate immune receptors or disease resistance (r) proteins contain a nb-lrr (nucleotide-binding site, leucine-rich repeat) structure. the recent findings regarding nb-lrr signaling are summarized in this article. an emerging theme is that two nb-lrrs can function together to mediate disease resistance against pathogen isolates. also, recent results delineate the nb-lrr protein fragments that are sufficient to initiate defense signaling. importantly, distinct fragments of d ... | 2010 | 20483655 |
| rpg1-b-derived resistance to avrb-expressing pseudomonas syringae requires rin4-like proteins in soybean. | soybean (glycine max) rpg1-b (for resistance to pseudomonas syringae pv glycinea) mediates species-specific resistance to p. syringae expressing the avirulence protein avrb, similar to the nonorthologous rpm1 in arabidopsis (arabidopsis thaliana). rpm1-derived signaling is presumably induced upon avrb-derived modification of the rpm1-interacting protein, rin4 (for rpm1-interacting 4). we show that, similar to rpm1, rpg1-b does not directly interact with avrb but associates with rin4-like protein ... | 2010 | 20484023 |
| experimental evidence that source genetic variation drives pathogen emergence. | a pathogen can readily mutate to infect new host types, but this does not guarantee successful establishment in the new habitat. what factors, then, dictate emergence success? one possibility is that the pathogen population cannot sustain itself on the new host type (i.e. host is a sink), but migration from a source population allows adaptive sustainability and eventual emergence by delivering beneficial mutations sampled from the source's standing genetic variation. this idea is relevant regard ... | 2010 | 20484240 |
| genome sequence of the plant growth promoting endophytic bacterium enterobacter sp. 638. | enterobacter sp. 638 is an endophytic plant growth promoting gamma-proteobacterium that was isolated from the stem of poplar (populus trichocarpaxdeltoides cv. h11-11), a potentially important biofuel feed stock plant. the enterobacter sp. 638 genome sequence reveals the presence of a 4,518,712 bp chromosome and a 157,749 bp plasmid (pent638-1). genome annotation and comparative genomics allowed the identification of an extended set of genes specific to the plant niche adaptation of this bacteri ... | 2010 | 20485560 |
| electromigration techniques--a fast and economical tool for differentiation of similar strains of microorganisms. | the detection and identification of pathogens currently relies upon a very diverse range of techniques and skills, from traditional cultivation and taxonomic procedures to modern rapid and sensitive diagnostic methods. real-time pcr is now exploited as a front line diagnostic screening tool in human, animal and plant health as well as bio-security. nevertheless, new techniques for pathogen identification, particularly of unknown samples, are needed. in this study we propose the combination of el ... | 2010 | 20485808 |
| the arabidopsis mitogen-activated protein kinase phosphatase pp2c5 affects seed germination, stomatal aperture, and abscisic acid-inducible gene expression. | abscisic acid (aba) is an important phytohormone regulating various cellular processes in plants, including stomatal opening and seed germination. although protein phosphorylation via mitogen-activated protein kinases (mapks) has been suggested to be important in aba signaling, the corresponding phosphatases are largely unknown. here, we show that a member of the protein phosphatase 2c (pp2c) family in arabidopsis (arabidopsis thaliana), pp2c5, is acting as a mapk phosphatase. the pp2c5 protein ... | 2010 | 20488890 |
| arabidopsis glutathione reductase1 plays a crucial role in leaf responses to intracellular hydrogen peroxide and in ensuring appropriate gene expression through both salicylic acid and jasmonic acid signaling pathways. | glutathione is a major cellular thiol that is maintained in the reduced state by glutathione reductase (gr), which is encoded by two genes in arabidopsis (arabidopsis thaliana; gr1 and gr2). this study addressed the role of gr1 in hydrogen peroxide (h(2)o(2)) responses through a combined genetic, transcriptomic, and redox profiling approach. to identify the potential role of changes in glutathione status in h(2)o(2) signaling, gr1 mutants, which show a constitutive increase in oxidized glutathio ... | 2010 | 20488891 |
| peptide-based antifungal therapies against emerging infections. | acquired drug resistance to mycotic infections is rapidly emerging as a major medical problem. opportunistic fungal infections create therapeutic challenges, particularly in high risk immunocompromised patients with aids, cancer, and those undergoing transplantation. higher mortality and/or morbidity rates due to invasive mycosis have been increasing over the last 20 years, and in light of growing resistance to commonly used antibiotics, novel antifungal drugs and approaches are required. curren ... | 2010 | 20495663 |
| the metabolic transition during disease following infection of arabidopsis thaliana by pseudomonas syringae pv. tomato. | summary the outcome of bacterial infection in plants is determined by the ability of the pathogen to successfully occupy the apoplastic space and deliver a constellation of effectors that collectively suppress basal and effector-triggered immune responses. in this study, we examined the metabolic changes associated with establishment of disease using analytical techniques that interrogated a range of chemistries. we demonstrated clear differences in the metabolome of arabidopsis thaliana leaves ... | 2010 | 20497374 |
| salmonella enterica serovar enteritidis tatb and tatc mutants are impaired in caco-2 cell invasion in vitro and show reduced systemic spread in chickens. | salmonella enterica subsp. enterica serovar enteritidis is a leading causative agent of gastroenteritis in humans. this pathogen also colonizes the intestinal tracts of poultry and can spread systemically in chickens. transfer to humans usually occurs through undercooked or improperly handled poultry meat or eggs. the bacterial twin-arginine transport (tat) pathway is responsible for the translocation of folded proteins across the cytoplasmic membrane. in order to study the role of the tat syste ... | 2010 | 20498258 |
| tobacco mosaic virus infection results in an increase in recombination frequency and resistance to viral, bacterial, and fungal pathogens in the progeny of infected tobacco plants. | our previous experiments showed that infection of tobacco (nicotiana tabacum) plants with tobacco mosaic virus (tmv) leads to an increase in homologous recombination frequency (hrf). the progeny of infected plants also had an increased rate of rearrangements in resistance gene-like loci. here, we report that tobacco plants infected with tmv exhibited an increase in hrf in two consecutive generations. analysis of global genome methylation showed the hypermethylated genome in both generations of p ... | 2010 | 20498336 |
| synthesis of 5-hydroxyectoine from ectoine: crystal structure of the non-heme iron(ii) and 2-oxoglutarate-dependent dioxygenase ectd. | as a response to high osmolality, many microorganisms synthesize various types of compatible solutes. these organic osmolytes aid in offsetting the detrimental effects of low water activity on cell physiology. one of these compatible solutes is ectoine. a sub-group of the ectoine producer's enzymatically convert this tetrahydropyrimidine into a hydroxylated derivative, 5-hydroxyectoine. this compound also functions as an effective osmostress protectant and compatible solute but it possesses prop ... | 2010 | 20498719 |
| transcriptional regulation of the crk/duf26 group of receptor-like protein kinases by ozone and plant hormones in arabidopsis. | plant receptor-like/pelle kinases (rlk) are a group of conserved signalling components that regulate developmental programs and responses to biotic and abiotic stresses. one of the largest rlk groups is formed by the domain of unknown function 26 (duf26) rlks, also called cysteine-rich receptor-like kinases (crks), which have been suggested to play important roles in the regulation of pathogen defence and programmed cell death. despite the vast number of rlks present in plants, however, only a f ... | 2010 | 20500828 |
| the arabidopsis nitrate transporter nrt1.8 functions in nitrate removal from the xylem sap and mediates cadmium tolerance. | long-distance transport of nitrate requires xylem loading and unloading, a successive process that determines nitrate distribution and subsequent assimilation efficiency. here, we report the functional characterization of nrt1.8, a member of the nitrate transporter (nrt1) family in arabidopsis thaliana. nrt1.8 is upregulated by nitrate. histochemical analysis using promoter-beta-glucuronidase fusions, as well as in situ hybridization, showed that nrt1.8 is expressed predominantly in xylem parenc ... | 2010 | 20501909 |
| visible fluorescence detection of type iii protein secretion from bacterial pathogens. | type iii protein secretion is essential for many gram-negative bacterial infections of host cells and an attractive target for new antibacterial drugs. here, we describe a bacterial protein effector-carboxypeptidase g2 (cpg2) reporter system for fluorescence and visible detection of type iii protein secretion in salmonella typhimurium. this system provides a general method for measuring protein expression and secretion as well as a high-throughput and quantitative assay for analyzing type iii pr ... | 2010 | 20504019 |
| lessons learned from type iii effector transgenic plants. | the gram negative bacterial phytopathogen pseudomonas syringae employs a molecular syringe termed the type iii secretion system (ttss) to deliver an array of type iii secreted effector (ttse) proteins into plant cells. the major function ascribed to type iii effectors of p. syringae is their ability to suppress plant immunity. because individual pathovars of p. syringae can possess over 30 ttses, functional redundancy can provide a hurdle to ascribing functions by ttse-deletion or -overexpressio ... | 2010 | 20505348 |
| different versions of pseudomonas syringae pv. tomato dc3000 exist due to the activity of an effector transposon. | summary the plant pathogenic bacterium pseudomonas syringae pv. tomato strain dc3000 is a key model organism to study plant-pathogen interactions. we realized that two versions of this strain, which carry plasmids of different sizes, exist in our strain collections. the difference was located to a 9.4-kb deletion within the larger of the two endogenous plasmids encompassing the partitioning genes para and parb and a putative mobile element encoding the type iii effector hopam1-2 (formerly avrppi ... | 2006 | 20507452 |
| extensin over-expression in arabidopsis limits pathogen invasiveness. | summary the function of the cell wall protein extensin has been the subject of much speculation since it was first isolated over 40 years ago. in order to investigate the role of extensins in plant defence, we used the gain-of-function strategy to generate transgenic arabidopsis plants over-expressing the ext1 extensin gene. these were infected with the virulent bacterial pathogen pseudomonas syringae dc3000 and symptom development was monitored. lesions on the transgenics were on average five-f ... | 2006 | 20507471 |
| a novel link between tomato gras genes, plant disease resistance and mechanical stress response. | summary members of the gras family of transcriptional regulators have been implicated in the control of plant growth and development, and in the interaction of plants with symbiotic bacteria. here we examine the complexity of the gras gene family in tomato (solanum lycopersicum) and investigate its role in disease resistance and mechanical stress. a large number of tomato ests corresponding to gras transcripts were retrieved from the public database and assembled in 17 contigs of putative genes. ... | 2006 | 20507472 |
| the phytotoxin coronatine from pseudomonas syringae pv. tomato dc3000 functions as a virulence factor and influences defence pathways in edible brassicas. | summary the phytotoxin coronatine (cor) contributes to the virulence of pseudomonas syringae pv. tomato (pst) strain dc3000 on arabidopsis thaliana and tomato. however, little is known regarding the role of cor in the virulence of dc3000 on cultivated brassica spp. in this study, the role of cor and its precursors, coronafacic acid (cfa) and coronamic acid (cma), were examined in the virulence of pst dc3000 on collard and turnip, two important edible brassicas. pst dc3000 and three well-defined ... | 2007 | 20507480 |
| disease resistance to bacterial pathogens affected by the amount of ferredoxin-i protein in plants. | summary ferredoxin-i (fd-i) is a fundamental protein that is involved in several metabolic pathways. the amount of fd-i found in plants is generally regulated by environmental stress, including biotic and abiotic events. in this study, the correlation between quantity of fd-i and plant disease resistance was investigated. fd-i levels were increased by inoculation with pseudomonas syringae pv. syringae but were reduced by erwinia carotovora ssp. carotovora. transgenic tobacco over-expressing fd-i ... | 2007 | 20507485 |
| the tobacco ntann12 gene, encoding an annexin, is induced upon rhodoccocus fascians infection and during leafy gall development. | summary annexins are calcium-binding proteins that have been associated in plants with different biological processes such as responses to abiotic stress and early nodulation stages. until now, the implication of annexins during plant-pathogen interactions has not been reported. here, a novel plant annexin gene induced in tobacco by-2 cell suspension cultures infected with the phytopathogenic bacterium rhodococcus fascians (strain d188) has been identified. expression of this gene, called ntann1 ... | 2007 | 20507490 |
| dspa/e, a type iii effector of erwinia amylovora, is required for early rapid growth in nicotiana benthamiana and causes nbsgt1-dependent cell death. | summary dspa/e is a pathogenicity factor of erwinia amylovora that is translocated into the plant cell cytoplasm through an hrp type iii secretion system. transient expression of dspa/e in nicotiana benthamiana or yeast induced cell death, as it does in n. tabacum and apple as described previously. dspa/e-induced cell death in n. benthamiana was not inhibited by coexpression of avrptob of pseudomonas syringae pv. tomato, which inhibits programmed cell death (pcd) induced by several other elicito ... | 2007 | 20507497 |
| competitive index in mixed infections: a sensitive and accurate assay for the genetic analysis of pseudomonas syringae-plant interactions. | summary: mixed infections have been broadly applied to the study of bacterial pathogens in animals. however, the application of mixed infection-based methods in plant pathogens has been very limited. an important factor for this limitation is the different dynamics that mixed infections have been reported to show in the different types of models. reports in systemic animal infections have shown that any bacterium has the same probability of multiplying within a mixed infection than in a single i ... | 2007 | 20507512 |
| the leucine-rich repeat (lrr) protein, calrr1, interacts with the hypersensitive induced reaction (hir) protein, cahir1, and suppresses cell death induced by the cahir1 protein. | summary: leucine-rich repeat proteins (lrrs) function in a number of signal transduction pathways via protein-protein interactions. the gene encoding a small protein of pepper, calrr1, is specifically induced upon pathogen challenge and treatment with pathogen-associated molecular patterns (pamps). we identified a pepper hypersensitive induced reaction (cahir1) protein that interacts with the lrr domain of the calrr1 protein using yeast two-hybrid screening. ectopic expression of the pepper cahi ... | 2007 | 20507517 |
| the 18mer peptaibols from trichoderma virens elicit plant defence responses. | summary peptaibols, the products of non-ribosomal peptide synthetases (nrps), are linear peptide antibiotics produced by trichoderma and other fungal genera. trichoderma virens strain gv29-8, a well-known biocontrol agent and inducer of plant defence responses, produces three lengths of peptaibols, 11, 14 and 18 residues long, with several isoforms of each. disruption of the nrps gene, tex1, encoded by a 62.8-kb uninterrupted open reading frame, results in the loss of production of all forms of ... | 2007 | 20507534 |
| disturbance of the ca(2+)/calmodulin-dependent signalling pathway is responsible for the resistance of arabidopsis dnd1 against pectobacterium carotovorum infection. | summary arabidopsis thaliana wild-type col-0 and its mutant, 'defence, no death' (dnd) 1-1, were infected with biotrophic pseudomonas syringae pv. tomato strain dc3000 and necrotrophic pectobacterium carotovorum strain kacc 10228, and cellular and molecular responses among them were then analysed. col-0 wild-type was susceptible to both pathogens. by contrast, neither dc3000 nor kacc 10228 infected dnd1-1 (yu et al., 1998. proc. natl. acad. sci. usa 95: 7819-7824). neither of the pathogens trigg ... | 2007 | 20507535 |
| activation of plant immune responses by a gain-of-function mutation in an atypical receptor-like kinase. | arabidopsis (arabidopsis thaliana) suppressor of npr1-1, constitutive1 (snc1) contains a gain-of-function mutation in a toll/interleukin receptor-nucleotide binding site-leucine-rich repeat resistance (r) protein and it has been a useful tool for dissecting r-protein-mediated immunity. here we report the identification and characterization of snc4-1d, a semidominant mutant with snc1-like phenotypes. snc4-1d constitutively expresses defense marker genes pr1, pr2, and pdf1.2, and displays enhanced ... | 2010 | 20508139 |
| microarray detection call methodology as a means to identify and compare transcripts expressed within syncytial cells from soybean (glycine max) roots undergoing resistant and susceptible reactions to the soybean cyst nematode (heterodera glycines). | background. a comparative microarray investigation was done using detection call methodology (dcm) and differential expression analyses. the goal was to identify genes found in specific cell populations that were eliminated by differential expression analysis due to the nature of differential expression methods. laser capture microdissection (lcm) was used to isolate nearly homogeneous populations of plant root cells. results. the analyses identified the presence of 13,291 transcripts between th ... | 2010 | 20508855 |
| nooks and crannies in type vi secretion regulation. | type vi secretion systems (t6ss) are macromolecular, transenvelope machines encoded within the genomes of most gram-negative bacteria, including plant, animal, and human pathogens, as well as soil and environmental isolates. t6ss are involved in a broad variety of functions: from pathogenesis to biofilm formation and stress sensing. this large array of functions is reflected by a vast diversity of regulatory mechanisms: repression by histone-like proteins and regulation by quorum sensing, transc ... | 2010 | 20511495 |
| atp modulates the growth of specific microbial strains. | the regulatory function of extracellular atp (exatp) in bacteria is unknown, but recent studies have demonstrated exatp induced enhanced secondary metabolite production and morphological differentiation in streptomyces coelicolor. the growth of streptomyces coelicolor, however, was unaffected by exatp, although changes in growth are common phenotypes. to identify bacteria whose growth is altered by exatp, we measured exatp-induced population changes in fast-growing microbes and actinomycetes in ... | 2011 | 20512647 |
| influence of soil fumigation by methyl bromide and methyl iodide on rhizosphere and phyllosphere microbial community structure. | rhizosphere and phyllosphere microbial communities were evaluated on roots and leaves of growth chamber-grown lettuce (lactuca sativa (l.) cv. green forest) plants by culture-dependent and -independent methods after soil fumigation. denaturing gradient gel electrophoresis (dgge) with 16s rrna primers followed by cloning and sequencing was used to identify major rrna bands from the rhizosphere and phyllosphere. three weeks after fumigation, there were no differences (p = 0.16) in rhizosphere micr ... | 2010 | 20512733 |
| stomata and pathogens: warfare at the gates. | bacteria and fungi are capable of triggering stomatal closure through pathogen-associated molecular patterns (pamps), which prevents penetration through these pores. therefore, the stomata can be considered part of the plant innate immune response. some pathogens have evolved mechanisms to evade stomatal defense. the bacterial pathogen xanthomonas campestris pv. campestris (xcc), which infects plants of the brassicaceae family mainly through hydathodes, has also been reported to infect plants th ... | 2009 | 20514224 |
| natural allelic variation underlying a major fitness trade-off in arabidopsis thaliana. | plants can defend themselves against a wide array of enemies, from microbes to large animals, yet there is great variability in the effectiveness of such defences, both within and between species. some of this variation can be explained by conflicting pressures from pathogens with different modes of attack. a second explanation comes from an evolutionary 'tug of war', in which pathogens adapt to evade detection, until the plant has evolved new recognition capabilities for pathogen invasion. if s ... | 2010 | 20520716 |
| involvement of salicylate and jasmonate signaling pathways in arabidopsis interaction with fusarium graminearum. | fusarium graminearum is the principal causative agent of fusarium head blight (fhb), a devastating disease of wheat and barley. this fungus can also colonize arabidopsis thaliana. disease resistance was enhanced in transgenic wheat and arabidopsis plants that constitutively overexpress the nonexpressor of pathogenesis-related genes 1 (npr1) gene, which regulates salicylic acid (sa) signaling and modulates the activation of jasmonic acid (ja)-dependent defenses. here, we provide several lines of ... | 2010 | 20521949 |
| pseudomonas syringae two-component response regulator rhpr regulates promoters carrying an inverted repeat element. | the two-component system rhprs was identified in pseudomonas syringae as a regulator of the genes encoding the type iii secretion system and type iii effector proteins (together called the t3 genes). in the absence of the sensor kinase rhps, the response regulator rhpr represses the induction of the t3 gene regulatory cascade consisting of hrprs, hrpl, and the t3 genes in a phosphorylation-dependent manner. the repressor activity of rhpr is inhibited by rhps, which presumably acts as a phosphata ... | 2010 | 20521955 |
| effector-triggered and pathogen-associated molecular pattern-triggered immunity differentially contribute to basal resistance to pseudomonas syringae. | pathogens induce pathogen-associated molecular pattern (pamp)-triggered immunity (pti) and effector-triggered immunity (eti) in plants. pamps are microbial molecules recognized by host plants as nonself signals, whereas pathogen effectors are evolved to aid in parasitism but are sometimes recognized by specific intracellular resistance proteins. in the absence of detectable eti determining classical incompatible interactions, basal resistance exists during compatible and nonhost interactions. wh ... | 2010 | 20521956 |
| the use of orthologous sequences to predict the impact of amino acid substitutions on protein function. | computational predictions of the functional impact of genetic variation play a critical role in human genetics research. for nonsynonymous coding variants, most prediction algorithms make use of patterns of amino acid substitutions observed among homologous proteins at a given site. in particular, substitutions observed in orthologous proteins from other species are often assumed to be tolerated in the human protein as well. we examined this assumption by evaluating a panel of nonsynonymous muta ... | 2010 | 20523748 |
| arabidopsis small ubiquitin-like modifier paralogs have distinct functions in development and defense. | posttranslational modifications allow dynamic and reversible changes to protein function. in arabidopsis thaliana, a small gene family encodes paralogs of the small ubiquitin-like posttranslational modifier. we studied the function of these paralogs. single mutants of the sum1 and sum2 paralogs do not exhibit a clear phenotype. however, the corresponding double knockdown mutant revealed that sum1 and sum2 are essential for plant development, floral transition, and suppression of salicylic acid ( ... | 2010 | 20525853 |
| rtx proteins: a highly diverse family secreted by a common mechanism. | repeats-in-toxin (rtx) exoproteins of gram-negative bacteria form a steadily growing family of proteins with diverse biological functions. their common feature is the unique mode of export across the bacterial envelope via the type i secretion system and the characteristic, typically nonapeptide, glycine- and aspartate-rich repeats binding ca(2+) ions. in this review, we summarize the current state of knowledge on the organization of rtx loci and on the biological and biochemical activities of t ... | 2010 | 20528947 |
| the differential spatial distribution of secondary metabolites in arabidopsis leaves reacting hypersensitively to pseudomonas syringae pv. tomato is dependent on the oxidative burst. | secondary metabolites (sms) play key roles in pathogen responses, although knowledge of their precise functions is limited by insufficient characterization of their spatial response. the present study addressed this issue in arabidopsis leaves by non-targeted and targeted metabolite profiling of pseudomonas syringae pv. tomato (pst-avrrpm1) infected and adjacent uninfected leaf tissues. while overlap was observed between infected and uninfected areas, the non-targeted metabolite profiles of thes ... | 2010 | 20530195 |
| defensin-like zmes4 mediates pollen tube burst in maize via opening of the potassium channel kzm1. | in contrast to animals and lower plant species, sperm cells of flowering plants are non-motile and are transported to the female gametes via the pollen tube, i.e. the male gametophyte. upon arrival at the female gametophyte two sperm cells are discharged into the receptive synergid cell to execute double fertilization. the first players involved in inter-gametophyte signaling to attract pollen tubes and to arrest their growth have been recently identified. in contrast the physiological mechanism ... | 2010 | 20532241 |
| soybean metabolites regulated in root hairs in response to the symbiotic bacterium bradyrhizobium japonicum. | nodulation of soybean (glycine max) root hairs by the nitrogen-fixing symbiotic bacterium bradyrhizobium japonicum is a complex process coordinated by the mutual exchange of diffusible signal molecules. a metabolomic study was performed to identify small molecules produced in roots and root hairs during the rhizobial infection process. metabolites extracted from roots and root hairs mock inoculated or inoculated with b. japonicum were analyzed by gas chromatography-mass spectrometry and ultraper ... | 2010 | 20534735 |
| cryo-electron tomography of bacteriophage phi6 procapsids shows random occupancy of the binding sites for rna polymerase and packaging ntpase. | assembly of dsrna bacteriophage phi6 involves packaging of the three mrna strands of the segmented genome into the procapsid, an icosahedrally symmetric particle with recessed vertices. the hexameric packaging ntpase (p4) overlies these vertices, and the monomeric rna-dependent rna polymerase (rdrp, p2) binds at sites inside the shell. p2 and p4 are present in substoichiometric amounts, raising the questions of whether they are recruited to the nascent procapsid in defined amounts and at specifi ... | 2010 | 20538059 |
| accumulation of isochorismate-derived 2,3-dihydroxybenzoic 3-o-beta-d-xyloside in arabidopsis resistance to pathogens and ageing of leaves. | an intricate network of hormone signals regulates plant development and responses to biotic and abiotic stress. salicylic acid (sa), derived from the shikimate/isochorismate pathway, is a key hormone in resistance to biotrophic pathogens. several sa derivatives and associated modifying enzymes have been identified and implicated in the storage and channeling of benzoic acid intermediates or as bioactive molecules. however, the range and modes of action of sa-related metabolites remain elusive. i ... | 2010 | 20538606 |
| an experimental study of the population and evolutionary dynamics of vibrio cholerae o1 and the bacteriophage jsf4. | studies of vibrio cholerae in the environment and infected patients suggest that the waning of cholera outbreaks is associated with rise in the density of lytic bacteriophage. in accordance with mathematical models, there are seemingly realistic conditions where phage predation could be responsible for declines in the incidence of cholera. here, we present the results of experiments with the el tor strain of v. cholerae (n16961) and a naturally occurring lytic phage (jsf4), exploring the validit ... | 2010 | 20538647 |
| extracellular fibrils of pathogenic yeast cryptococcus gattii are important for ecological niche, murine virulence and human neutrophil interactions. | cryptococcus gattii, an emerging fungal pathogen of humans and animals, is found on a variety of trees in tropical and temperate regions. the ecological niche and virulence of this yeast remain poorly defined. we used arabidopsis thaliana plants and plant-derived substrates to model c. gattii in its natural habitat. yeast cells readily colonized scratch-wounded plant leaves and formed distinctive extracellular fibrils (40-100 nm diameter x500-3000 nm length). extracellular fibrils were observed ... | 2010 | 20539754 |
| in planta gene expression analysis of xanthomonas oryzae pathovar oryzae, african strain mai1. | bacterial leaf blight causes significant yield losses in rice crops throughout asia and africa. although both the asian and african strains of the pathogen, xanthomonas oryzae pv. oryzae (xoo), induce similar symptoms, they are nevertheless genetically different, with the african strains being more closely related to the asian x. oryzae pv. oryzicola (xoc). | 2010 | 20540733 |
| specific and rapid enumeration of viable but nonculturable and viable-culturable gram-negative bacteria by using flow cytometry. | an issue of critical concern in microbiology is the ability to detect viable but nonculturable (vbnc) and viable-culturable (vc) cells by methods other than existing approaches. culture methods are selective and underestimate the real population, and other options (direct viable count and the double-staining method using epifluorescence microscopy and inhibitory substance-influenced molecular methods) are also biased and time-consuming. a rapid approach that reduces selectivity, decreases bias f ... | 2010 | 20543046 |
| recombineering using recte from pseudomonas syringae. | in this report, we describe the identification of functions that promote genomic recombination of linear dna introduced into pseudomonas cells by electroporation. the genes encoding these functions were identified in pseudomonas syringae pv. syringae b728a based on similarity to the lambda red exo/beta and recet proteins encoded by the lambda and rac bacteriophages of escherichia coli. the ability of the pseudomonad-encoded proteins to promote recombination was tested in p. syringae pv. tomato d ... | 2010 | 20543050 |
| peroxisomal hydrogen peroxide is coupled to biotic defense responses by isochorismate synthase1 in a daylength-related manner. | while it is well established that reactive oxygen species can induce cell death, intracellularly generated oxidative stress does not induce lesions in the arabidopsis (arabidopsis thaliana) photorespiratory mutant cat2 when plants are grown in short days (sd). one interpretation of this observation is that a function necessary to couple peroxisomal hydrogen peroxide (h(2)o(2))-triggered oxidative stress to cell death is only operative in long days (ld). like lesion formation, pathogenesis-relate ... | 2010 | 20543092 |
| an mrna blueprint for c4 photosynthesis derived from comparative transcriptomics of closely related c3 and c4 species. | c(4) photosynthesis involves alterations to the biochemistry, cell biology, and development of leaves. together, these modifications increase the efficiency of photosynthesis, and despite the apparent complexity of the pathway, it has evolved at least 45 times independently within the angiosperms. to provide insight into the extent to which gene expression is altered between c(3) and c(4) leaves, and to identify candidates associated with the c(4) pathway, we used massively parallel mrna sequenc ... | 2010 | 20543093 |
| an mrna blueprint for c4 photosynthesis derived from comparative transcriptomics of closely related c3 and c4 species. | c(4) photosynthesis involves alterations to the biochemistry, cell biology, and development of leaves. together, these modifications increase the efficiency of photosynthesis, and despite the apparent complexity of the pathway, it has evolved at least 45 times independently within the angiosperms. to provide insight into the extent to which gene expression is altered between c(3) and c(4) leaves, and to identify candidates associated with the c(4) pathway, we used massively parallel mrna sequenc ... | 2010 | 20543093 |
| e3 ubiquitin ligase activity and targeting of bat3 by multiple legionella pneumophila translocated substrates. | the intracellular bacterial pathogen legionella pneumophila modulates a number of host processes during intracellular growth, including the eukaryotic ubiquitination machinery, which dictates the stability, activity, and/or localization of a large number of proteins. a number of l. pneumophila proteins contain eukaryotic-like motifs typically associated with ubiquitination. central among these is a family of five f-box-domain-containing proteins of legionella pneumophila. each of these five prot ... | 2010 | 20547746 |
| aspartate aminotransferase is involved in cold adaptation in psychrophilic pseudomonas syringae. | csm2, a cold-sensitive mutant of psychrophilic pseudomonas syringae, grows like wild-type cells when cultured at 22 and 28 degrees c; but at 4 degrees c, the growth is retarded. in csm2, aat (coding for aspartate aminotransferase) is identified as the mutated gene. the expression of aat in pseudomonas syringae was transiently enhanced when cells were shifted from 22 to 4 degrees c indicating that aat is cold-inducible. complementation of the mutated aat transformed csm2 from a cold-sensitive phe ... | 2010 | 20552170 |
| interference of quorum sensing in pseudomonas syringae by bacterial epiphytes that limit iron availability. | leaf surfaces harbour bacterial epiphytes that are capable of influencing the quorum sensing (qs) system, density determination through detection of diffusible signal molecules, of the plant-pathogen pseudomonas syringae pv. syringae (pss) which controls expression of extracellular polysaccharide production, motility and other factors contributing to virulence to plants. approximately 11% of the bacterial epiphytes recovered from a variety of plants produced a diffusible factor capable of inhibi ... | 2010 | 20553555 |
| comparative transcriptional profiling-based identification of raphanusanin-inducible genes. | raphanusanin (ra) is a light-induced growth inhibitor involved in the inhibition of hypocotyl growth in response to unilateral blue-light illumination in radish seedlings. knowledge of the roles of ra still remains elusive. to understand the roles of ra and its functional coupling to light signalling, we constructed the ra-induced gene library using the suppression subtractive hybridisation (ssh) technique and present a comparative investigation of gene regulation in radish seedlings in response ... | 2010 | 20553608 |
| short signalling distances make plant communication a soliloquy. | plants respond to attack by herbivores or pathogens with the release of volatile organic compounds. neighbouring plants can receive these volatiles and consecutively induce their own defence arsenal. this 'plant communication', however, appears counterintuitive when it benefits independent and genetically unrelated receivers, which may compete with the emitter. as a solution to this problem, a role for volatile compounds in within-plant signalling has been predicted. we used wild-type lima bean ... | 2010 | 20554558 |
| prokaryote-derived protein inhibitors of peptidases: a sketchy occurrence and mostly unknown function. | in metazoan organisms protein inhibitors of peptidases are important factors essential for regulation of proteolytic activity. in vertebrates genes encoding peptidase inhibitors constitute up to 1% of genes reflecting a need for tight and specific control of proteolysis especially in extracellular body fluids. in stark contrast unicellular organisms, both prokaryotic and eukaryotic consistently contain only few, if any, genes coding for putative peptidase inhibitors. this may seem perplexing in ... | 2010 | 20558234 |
| specific resistances against pseudomonas syringae effectors avrb and avrrpm1 have evolved differently in common bean (phaseolus vulgaris), soybean (glycine max), and arabidopsis thaliana. | *in plants, the evolution of specific resistance is poorly understood. pseudomonas syringae effectors avrb and avrrpm1 are recognized by phylogenetically distinct resistance (r) proteins in arabidopsis thaliana (brassicaceae) and soybean (glycine max, fabaceae). in soybean, these resistances are encoded by two tightly linked r genes, rpg1-b and rpg1-r. to study the evolution of these specific resistances, we investigated avrb- and avrrpm1-induced responses in common bean (phaseolus vulgaris, fab ... | 2010 | 20561214 |
| molecular analysis of two bacterioferritin genes, bfralpha and bfrbeta, in the model rhizobacterium pseudomonas putida kt2440. | the model rhizobacterium pseudomonas putida kt2440 and other fluorescent pseudomonads possess two bacterioferritins, bfralpha and bfrbeta. however, the regulatory systems controlling the expression of these genes and the roles of these proteins in iron homeostasis are ill defined. our studies show that both bfralpha and bfrbeta were monocistronic: promoter motifs and transcriptional start sites were identified, and fur boxes and sigma(s)-dependent regulatory motifs were absent. the expressions o ... | 2010 | 20562273 |
| novel high-throughput detection method to assess bacterial surfactant production. | a novel biosurfactant detection assay was developed for the observation of surfactants on agar plates. by using an airbrush to apply a fine mist of oil droplets, surfactants can be observed instantaneously as halos around biosurfactant-producing colonies. this atomized oil assay can detect a wide range of different synthetic and bacterially produced surfactants. this method could detect much lower concentrations of many surfactants than a commonly used water drop collapse method. it is semiquant ... | 2010 | 20562275 |
| the pcr amplification and characterization of entire pseudomonas syringae hrp/hrc clusters. | summary we describe the use of degenerate primers to amplify the core hrp/hrc region of p. syringae pv. phaseolicola nps3121. 18 826 bp were amplified using long-range pcr, digested and shotgun sequenced. sequence analysis finds a hypervariable region between the hrpu and hrpc operons, and indications of positive selection on the hrpe locus. the primers were also shown to work on four other, widely divergent p. syringae strains. these primers should be of great utility for the characterization o ... | 2004 | 20565590 |
| the jasmonate-insensitive mutant jin1 shows increased resistance to biotrophic as well as necrotrophic pathogens. | summary jasmonic acid and related oxylipin compounds are plant signalling molecules that are involved in the response to pathogens, insects, wounding and ozone. to explore further the role of jasmonates in stress signal transduction, the response of two jasmonate-signalling mutants, jin1 and jin4, to pathogens and ozone was analysed in this study. upon treatment with the biotrophic bacterial pathogen pseudomonas syringae, endogenous jasmonate levels increased in jin1 and jin4 similar to wild-typ ... | 2004 | 20565618 |
| an arabidopsis mutant with altered hypersensitive response to xanthomonas campestris pv. campestris, hxc1, displays a complex pathophenotype. | summary the hxc1 mutant was identified by screening an ems (ethylmethane sulphonate) mutagenized population of arabidopsis col-0 plants for an altered hypersensitive response (hr), after spray inoculation with an hr-inducing isolate of xanthomonas campestris pv. campestris (xcc) (strain 147). the hxc1 mutant shows a susceptible phenotype several days after initiation of the interaction with the avirulent strain. this macroscopically observed phenotype was confirmed by measurement of in planta ba ... | 2004 | 20565620 |
| a constitutive pr-1::luciferase expression screen identifies arabidopsis mutants with differential disease resistance to both biotrophic and necrotrophic pathogens. | summary a complex signal transduction network involving salicylic acid, jasmonic acid and ethylene underlies disease resistance in arabidopsis. to understand this defence signalling network further, we identified mutants that expressed the marker gene pr-1::luciferase in the absence of pathogen infection. these cir mutants all display constitutive expression of a suite of defence-related genes but exhibit different disease resistance profiles to two biotrophic pathogens, pseudomonas syringae pv. ... | 2005 | 20565636 |
| lineage-specific regions in pseudomonas syringae pv tomato dc3000. | summary comparative analyses of the chromosome of pseudomonas syringae pv tomato dc3000 with the finished, complete genomes of pseudomonas aeruginosa pao1, an animal pathogen, and the non-pathogenic soil inhabitant pseudomonas putida kt2440 revealed a high degree of sequence conservation in genes involved in 'housekeeping functions'. however, divergence is present among these three fluorescent pseudomonads, yielding 'suites' of species-specific genes that may provide the genetic basis for adapta ... | 2005 | 20565638 |
| coronatine and salicylic acid: the battle between arabidopsis and pseudomonas for phytohormone control. | summary the phytotoxin coronatine is a jasmonate mimic produced by pseudomonas syringae pv. tomato (pst). coronatine acts as a virulence factor in arabidopsis and mutants insensitive to coronatine are resistant to pst and have higher levels of salicylic acid (sa). in this work we used the sa-deficient lines nahg and sid2-2 to determine if coronatine acts directly as a virulence factor or indirectly by sa suppression. using coronatine-deficient pst mutants we demonstrated that the lack of coronat ... | 2005 | 20565640 |
| cdna-aflp reveals genes differentially expressed during the hypersensitive response of cassava. | summary the tropical staple cassava is subject to several major diseases, such as cassava bacterial blight, caused by xanthomonas axonopodis pv. manihotis. disease-resistant genotypes afford the only practical solution, yet despite the global importance of this crop, little is known about its defence mechanisms. cdna-aflp was used to isolate cassava genes differentially expressed during the hypersensitive reaction (hr) of leaves in response to an incompatible pseudomonas syringae pathovar. seven ... | 2005 | 20565643 |
| the hrp pathogenicity island of erwinia amylovora and identification of three novel genes required for systemic infectiondouble dagger. | summary sequence analysis of the region bordering the hrp/dsp gene cluster of erwinia amylovora strain ea321, which causes fire blight, revealed characteristics of pathogenicity islands (pais). included are genes for a phage integrase, a trna(phe), several orthologues of genes of yapi, a pai of yersinia pseudotuberculosis, and several putative virulence genes with hrpl-dependent promoter motifs. the island is designated the hrp pai of e. amylovora. it is comprised of a chromosomal region of c. 6 ... | 2005 | 20565644 |
| determinants of pseudomonas putida wcs358 involved in inducing systemic resistance in plants. | summary pseudomonas putida wcs358 is a plant growth-promoting rhizobacterium originally isolated from the rhizosphere of potato. it can suppress soil-borne plant diseases by siderophore-mediated competition for iron, but it has also been reported to result in induced systemic resistance (isr) in arabidopsis thaliana. bacterial determinants of this strain involved in inducing systemic resistance in arabidopsis were investigated using a tn5 transposon mutant defective in biosynthesis of the fluore ... | 2005 | 20565648 |