Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| photorhabdus luminescens genes induced upon insect infection. | photorhabdus luminescens is a gram-negative luminescent enterobacterium and a symbiote to soil nematodes belonging to the species heterorhabditis bacteriophora. p.luminescens is simultaneously highly pathogenic to insects. this bacterium exhibits a complex life cycle, including one symbiotic stage characterized by colonization of the upper nematode gut, and a pathogenic stage, characterized by release from the nematode into the hemocoel of insect larvae, resulting in rapid insect death caused by ... | 2008 | 18489737 |
| nitrogen fixation island and rhizosphere competence traits in the genome of root-associated pseudomonas stutzeri a1501. | the capacity to fix nitrogen is widely distributed in phyla of bacteria and archaea but has long been considered to be absent from the pseudomonas genus. we report here the complete genome sequencing of nitrogen-fixing root-associated pseudomonas stutzeri a1501. the genome consists of a single circular chromosome with 4,567,418 bp. comparative genomics revealed that, among 4,146 protein-encoding genes, 1,977 have orthologs in each of the five other pseudomonas representative species sequenced to ... | 2008 | 18495935 |
| functional analysis reveals pleiotropic effects of rice ring-h2 finger protein gene osbirf1 on regulation of growth and defense responses against abiotic and biotic stresses. | ring finger proteins comprise a large family and play key roles in regulating growth/developmental processes, hormone signaling and responses to biotic and abiotic stresses in plants. a rice gene, osbirf1, encoding a putative ring-h2 finger protein, was cloned and identified. osbirf1 encodes a 396 amino acid protein belonging to the atl family characterized by a conserved ring-h2 finger domain (c-x2-c-x15-c-x1-h-x2-h-x2-c-x10-c-x2-c), a transmembrane domain at the n-terminal, a basic amino acid ... | 2008 | 18496756 |
| evolution of catalases from bacteria to humans. | excessive hydrogen peroxide is harmful for almost all cell components, so its rapid and efficient removal is of essential importance for aerobically living organisms. conversely, hydrogen peroxide acts as a second messenger in signal-transduction pathways. h(2)o(2) is degraded by peroxidases and catalases, the latter being able both to reduce h(2)o(2) to water and to oxidize it to molecular oxygen. nature has evolved three protein families that are able to catalyze this dismutation at reasonable ... | 2008 | 18498226 |
| the dark side of the salad: salmonella typhimurium overcomes the innate immune response of arabidopsis thaliana and shows an endopathogenic lifestyle. | salmonella enterica serovar typhimurium contaminated vegetables and fruits are considerable sources of human infections. bacteria present in raw plant-derived nutrients cause salmonellosis, the world wide most spread food poisoning. this facultative endopathogen enters and replicates in host cells and actively suppresses host immune responses. although salmonella survives on plants, the underlying bacterial infection mechanisms are only poorly understood. in this report we investigated the possi ... | 2008 | 18509467 |
| roles of rna polymerase iv in gene silencing. | eukaryotes typically have three multi-subunit enzymes that decode the nuclear genome into rna: dna-dependent rna polymerases i, ii and iii (pol i, ii and iii). remarkably, higher plants have five multi-subunit nuclear rna polymerases: the ubiquitous pol i, ii and iii, which are essential for viability; plus two non-essential polymerases, pol iva and pol ivb, which specialize in small rna-mediated gene silencing pathways. there are numerous examples of phenomena that require pol iva and/or pol iv ... | 2008 | 18514566 |
| mapk signaling regulates nitric oxide and nadph oxidase-dependent oxidative bursts in nicotiana benthamiana. | nitric oxide (no) and reactive oxygen species (ros) act as signals in innate immunity in plants. the radical burst is induced by inf1 elicitin, produced by the oomycete pathogen phytophthora infestans. no associated1 (noa1) and nadph oxidase participate in the radical burst. here, we show that mitogen-activated protein kinase (mapk) cascades mek2-sipk/ntf4 and mek1-ntf6 participate in the regulation of the radical burst. no generation was induced by conditional activation of sipk/ntf4, but not b ... | 2008 | 18515503 |
| complete genome sequence of the complex carbohydrate-degrading marine bacterium, saccharophagus degradans strain 2-40 t. | the marine bacterium saccharophagus degradans strain 2-40 (sde 2-40) is emerging as a vanguard of a recently discovered group of marine and estuarine bacteria that recycles complex polysaccharides. we report its complete genome sequence, analysis of which identifies an unusually large number of enzymes that degrade >10 complex polysaccharides. not only is this an extraordinary range of catabolic capability, many of the enzymes exhibit unusual architecture including novel combinations of catalyti ... | 2008 | 18516288 |
| lipodepsipeptides from pseudomonas syringae are partially proteolyzed and are not absorbed by humans: an in vitro study. | there are some concerns about the use of pseudomonas-based products as biocontrol agents because of the hemolytic activity shown by their metabolites. the effects of pseudomonas lipodepsipeptides (ldps) on mammals via ingestion and the ldp degradation during the digestion and intestinal permeability have not been evaluated. in this research, the susceptibility of different ldps to degradation was assayed with enzymatic gastrointestinal digestion, and intestinal permeability to ldps was investiga ... | 2008 | 18522033 |
| studies on dna-binding selectivity of wrky transcription factors lend structural clues into wrky-domain function. | wrky transcription factors have been shown to play a major role in regulating, both positively and negatively, the plant defense transcriptome. nearly all studied wrky factors appear to have a stereotypic binding preference to one dna element termed the w-box. how specificity for certain promoters is accomplished therefore remains completely unknown. in this study, we tested five distinct arabidopsis wrky transcription factor subfamily members for their dna binding selectivity towards variants o ... | 2008 | 18523729 |
| rna silencing in plants: yesterday, today, and tomorrow. | 2008 | 18524877 | |
| bioinformatic tools for inferring functional information from plant microarray data: tools for the first steps. | microarrays are a very powerful tool for quantifying the amount of rna in samples; however, their ability to query essentially every gene in a genome, which can number in the tens of thousands, presents analytical and interpretative problems. as a result, a variety of software and web-based tools have been developed to help with these issues. this article highlights and reviews some of the tools for the first steps in the analysis of a microarray study. we have tried for a balance between free a ... | 2008 | 18528524 |
| pr-13/thionin but not pr-1 mediates bacterial resistance in nicotiana attenuata in nature, and neither influences herbivore resistance. | increases in pathogenesis-related (pr) transcripts are commonly interpreted as evidence of plants' resistance responses to pathogens; however, few studies have examined whether increases in pr proteins protect plants growing under natural conditions. pseudomonas syringae pv. tomato dc3,000, which is virulent and causes disease in arabidopsis, is also pathogenic to the native tobacco nicotiana attenuata. n. attenuata responds to p. syringae pv. tomato dc3,000's challenges with increases in salicy ... | 2008 | 18533839 |
| surface display of gfp by pseudomonas syringae truncated ice nucleation protein in attenuated vibrio anguillarum strain. | microbial cell surface display of foreign proteins has been widely developed for many potential applications in live vaccine construction, whole-cell biocatalysts, and bioadsorption. to investigate the feasibility of displaying heterologous proteins on the surface of attenuated vibrio anguillarum strain for potential multivalent live vaccine development, different display systems were built upon a truncated ice nucleation protein (inp) from pseudomonas syringae icmp3023 whose n- and c-terminal d ... | 2008 | 18535860 |
| kinetics of salicylate-mediated suppression of jasmonate signaling reveal a role for redox modulation. | cross talk between salicylic acid (sa) and jasmonic acid (ja) signaling pathways plays an important role in the regulation and fine tuning of induced defenses that are activated upon pathogen or insect attack. pharmacological experiments revealed that transcription of ja-responsive marker genes, such as pdf1.2 and vsp2, is highly sensitive to suppression by sa. this antagonistic effect of sa on ja signaling was also observed when the ja pathway was biologically activated by necrotrophic pathogen ... | 2008 | 18539774 |
| virus adaptation by manipulation of host's gene expression. | viruses adapt to their hosts by evading defense mechanisms and taking over cellular metabolism for their own benefit. alterations in cell metabolism as well as side-effects of antiviral responses contribute to symptoms development and virulence. sometimes, a virus may spill over from its usual host species into a novel one, where usually will fail to successfully infect and further transmit to new host. however, in some cases, the virus transmits and persists after fixing beneficial mutations th ... | 2008 | 18545680 |
| deciphering the ubiquitin-mediated pathway in apicomplexan parasites: a potential strategy to interfere with parasite virulence. | reversible modification of proteins through the attachment of ubiquitin or ubiquitin-like modifiers is an essential post-translational regulatory mechanism in eukaryotes. the conjugation of ubiquitin or ubiquitin-like proteins has been demonstrated to play roles in growth, adaptation and homeostasis in all eukaryotes, with perturbation of ubiquitin-mediated systems associated with the pathogenesis of many human diseases, including cancer and neurodegenerative disorders. | 2008 | 18545708 |
| a critical role of two positively charged amino acids in the jas motif of arabidopsis jaz proteins in mediating coronatine- and jasmonoyl isoleucine-dependent interactions with the coi1 f-box protein. | summary: coronatine is an important virulence factor produced by several pathovars of the bacterial pathogen pseudomonas syringae. the structure of coronatine is similar to that of a class of plant hormones called jasmonates (jas). an important step in ja signaling is the scf(coi1) e3 ubiquitin ligase-dependent degradation of jaz repressor proteins. we have recently shown that jasmonoyl isoleucine (ja-ile) promotes physical interaction between arabidopsis jaz1 and coi1 (the f-box component of sc ... | 2008 | 18547396 |
| the structure of "defective in induced resistance" protein of arabidopsis thaliana, dir1, reveals a new type of lipid transfer protein. | screening of transfer dna (tdna) tagged lines of arabidopsis thaliana for mutants defective in systemic acquired resistance led to the characterization of dir1-1 (defective in induced resistance [systemic acquired resistance, sar]) mutant. it has been suggested that the protein encoded by the dir1 gene, i.e., dir1, is involved in the long distance signaling associated with sar. dir1 displays the cysteine signature of lipid transfer proteins, suggesting that the systemic signal could be lipid mol ... | 2008 | 18552128 |
| the histidine kinase ahk5 integrates endogenous and environmental signals in arabidopsis guard cells. | stomatal guard cells monitor and respond to environmental and endogenous signals such that the stomatal aperture is continually optimised for water use efficiency. a key signalling molecule produced in guard cells in response to plant hormones, light, carbon dioxide and pathogen-derived signals is hydrogen peroxide (h(2)o(2)). the mechanisms by which h(2)o(2) integrates multiple signals via specific signalling pathways leading to stomatal closure is not known. | 2008 | 18560512 |
| saccharides cross-reactive with bacillus anthracis spore glycoprotein as an anthrax vaccine component. | bacillus anthracis is a spore-forming bacterium that causes anthrax in humans and in other mammals. the glycoprotein bcla (bacillus collagen-like protein of anthracis) is a major constituent of the exosporium, the outermost surface of b. anthracis spores. the glycosyl part of bcla is an oligosaccharide composed of 2-o-methyl-4-(3-hydroxy-3-methylbutanamido)-4,6-dideoxy-d-glucose, referred to as anthrose, and three rhamnose residues. a structure similar to anthrose, 4-(3-hydroxy-3-methylbutanamid ... | 2008 | 18562275 |
| a two-genome microarray for the rice pathogens xanthomonas oryzae pv. oryzae and x. oryzae pv. oryzicola and its use in the discovery of a difference in their regulation of hrp genes. | xanthomonas oryzae pv. oryzae (xoo) and x. oryzae pv. oryzicola (xoc) are bacterial pathogens of the worldwide staple and grass model, rice. xoo and xoc are closely related but xoo invades rice vascular tissue to cause bacterial leaf blight, a serious disease of rice in many parts of the world, and xoc colonizes the mesophyll parenchyma to cause bacterial leaf streak, a disease of emerging importance. both pathogens depend on hrp genes for type iii secretion to infect their host. we constructed ... | 2008 | 18564427 |
| quorum sensing coordinates brute force and stealth modes of infection in the plant pathogen pectobacterium atrosepticum. | quorum sensing (qs) in vitro controls production of plant cell wall degrading enzymes (pcwdes) and other virulence factors in the soft rotting enterobacterial plant pathogen pectobacterium atrosepticum (pba). here, we demonstrate the genome-wide regulatory role of qs in vivo during the pba-potato interaction, using a pba-specific microarray. we show that 26% of the pba genome exhibited differential transcription in a qs (expi-) mutant, compared to the wild-type, suggesting that qs may make a gre ... | 2008 | 18566662 |
| arginase-negative mutants of arabidopsis exhibit increased nitric oxide signaling in root development. | mutation of either arginase structural gene (argah1 or argah2 encoding arginine [arg] amidohydrolase-1 and -2, respectively) resulted in increased formation of lateral and adventitious roots in arabidopsis (arabidopsis thaliana) seedlings and increased nitric oxide (no) accumulation and efflux, detected by the fluorogenic traps 3-amino,4-aminomethyl-2',7'-difluorofluorescein diacetate and diamino-rhodamine-4m, respectively. upon seedling exposure to the synthetic auxin naphthaleneacetic acid, no ... | 2008 | 18567826 |
| roles of arabidopsis wrky3 and wrky4 transcription factors in plant responses to pathogens. | plant wrky dna-binding transcription factors are involved in plant responses to biotic and abiotic responses. it has been previously shown that arabidopsis wrky3 and wrky4, which encode two structurally similar wrky transcription factors, are induced by pathogen infection and salicylic acid (sa). however, the role of the two wrky transcription factors in plant disease resistance has not been directly analyzed. | 2008 | 18570649 |
| a rice serine carboxypeptidase-like gene osbiscpl1 is involved in regulation of defense responses against biotic and oxidative stress. | serine carboxypeptidase-like proteins (scpls) comprise a large family of protein hydrolyzing enzymes that play roles in multiple cellular processes. during the course of study aimed at elucidating the molecular basis of induced immunity in rice, a gene, osbiscpl1, encoding a putative scpl, was isolated and identified. osbiscpl1 contains a conserved peptidase s10 domain, serine active site and a signal peptide at n-terminus. osbiscpl1 is expressed ubiquitously in rice, including roots, stems, lea ... | 2008 | 18571878 |
| overexpression of a rice defense-related f-box protein gene osdrf1 in tobacco improves disease resistance through potentiation of defense gene expression. | f-box proteins play important roles in plant growth/development and responses to environmental stimuli through targeting substrates into degradation machinery. a rice defense-related f-box protein gene, osdrf1, was cloned and identified during a course of study aimed at elucidating the molecular basis of induced immunity in rice. osdrf1 encodes a protein of 328 amino acids, containing a highly conserved f-box domain. expression of osdrf1 was induced upon treatment with benzothiadiazole (bth), a ... | 2008 | 18573188 |
| development of biocontrol agents from food microbial isolates for controlling post-harvest peach brown rot caused by monilinia fructicola. | an unconventional strategy of screening food microbes for biocontrol activity was used to develop biocontrol agents for controlling post-harvest peach brown rot caused by monilinia fructicola. forty-four microbial isolates were first screened for their biocontrol activity on apple fruit. compared with the pathogen-only check, seven of the 44 isolates reduced brown rot incidence by >50%, including four bacteria: bacillus sp. c06, lactobacillus sp. c03-b and bacillus sp. t03-c, lactobacillus sp. p ... | 2008 | 18573559 |
| expression of ethylene-forming enzyme (efe) of pseudomonas syringae pv. glycinea in trichoderma viride. | the efe gene encoding an ethylene-forming enzyme from pseudomonas syringae pv. glycinea has been expressed for the first time under the control of trichoderma reesei cbh1 promoter in trichoderma viride. reverse transcription polymerase chain reaction analysis showed that transformant y2 produced mrna of the efe gene. southern blot analysis showed that there was one copy of efe gene which was integrated into the chromosomal dna of t. viride. ethylene production by transformant y2 was efficiently ... | 2008 | 18575855 |
| folding kinetics and thermodynamics of pseudomonas syringae effector protein avrpto provide insight into translocation via the type iii secretion system. | in order to infect their hosts, many gram-negative bacteria translocate agents of infection, called effector proteins, through the type iii secretion system (ttss) into the host cytoplasm. this process is thought to require at least partial unfolding of these agents, raising the question of how an effector protein might unfold to enable its translocation and then refold once it reaches the host cytoplasm. avrpto is a well-studied effector protein of pseudomonas syringae pv tomato. the presence o ... | 2008 | 18577754 |
| jasmonate signaling: a conserved mechanism of hormone sensing. | the lipid-derived hormone jasmonate (ja) regulates diverse aspects of plant immunity and development. among the central components of the ja signaling cascade are the e3 ubiquitin ligase scfcoi1 and jasmonate zim-domain (jaz) proteins that repress transcription of ja-responsive genes. recent studies provide evidence that amino acid-conjugated forms of ja initiate signal transduction upon formation of a coronatine-insensitive1 (coi1)-ja-jaz ternary complex in which jazs are ubiquitinated and subs ... | 2008 | 18583180 |
| hpac controls substrate specificity of the xanthomonas type iii secretion system. | the gram-negative bacterial plant pathogen xanthomonas campestris pv. vesicatoria employs a type iii secretion (t3s) system to inject bacterial effector proteins into the host cell cytoplasm. one essential pathogenicity factor is hrpb2, which is secreted by the t3s system. we show that secretion of hrpb2 is suppressed by hpac, which was previously identified as a t3s control protein. since hpac promotes secretion of translocon and effector proteins but inhibits secretion of hrpb2, hpac presumabl ... | 2008 | 18584024 |
| statistical analysis of efficient unbalanced factorial designs for two-color microarray experiments. | experimental designs that efficiently embed a fixed effects treatment structure within a random effects design structure typically require a mixed-model approach to data analyses. although mixed model software tailored for the analysis of two-color microarray data is increasingly available, much of this software is generally not capable of correctly analyzing the elaborate incomplete block designs that are being increasingly proposed and used for factorial treatment structures. that is, optimize ... | 2008 | 18584033 |
| abscisic acid-mediated suppression of systemic acquired resistance signaling. | 2008 | 18586867 | |
| antagonistic interaction between systemic acquired resistance and the abscisic acid-mediated abiotic stress response in arabidopsis. | systemic acquired resistance (sar) is a potent innate immunity system in plants that is effective against a broad range of pathogens. sar development in dicotyledonous plants, such as tobacco (nicotiana tabacum) and arabidopsis thaliana, is mediated by salicylic acid (sa). here, using two types of sar-inducing chemicals, 1,2-benzisothiazol-3(2h)-one1,1-dioxide and benzo(1,2,3)thiadiazole-7-carbothioic acid s-methyl ester, which act upstream and downstream of sa in the sar signaling pathway, resp ... | 2008 | 18586869 |
| a rapid and robust method for simultaneously measuring changes in the phytohormones aba, ja and sa in plants following biotic and abiotic stress. | we describe an efficient method for the rapid quantitative determination of the abundance of three acidic plant hormones from a single crude extract directly by lc/ms/ms. the method exploits the sensitivity of ms and uses multiple reaction monitoring and isotopically labelled samples to quantify the phytohormones abscisic acid, jasmonic acid and salicylic acid in arabidopsis leaf tissue. | 2008 | 18590529 |
| transcriptional responses of arabidopsis thaliana during wilt disease caused by the soil-borne phytopathogenic bacterium, ralstonia solanacearum. | bacterial wilt is a common disease that causes severe yield and quality losses in many plants. in the present study, we used the model ralstonia solanacearum-arabidopsis thaliana pathosystem to study transcriptional changes associated with wilt disease development. susceptible col-5 plants and rrs1-r-containing resistant nd-1 plants were root-inoculated with r. solanacearum strains harbouring or lacking the matching popp2 avirulence gene. gene expression was marginally affected in leaves during ... | 2008 | 18596930 |
| tomato protein kinase 1b mediates signaling of plant responses to necrotrophic fungi and insect herbivory. | the tomato protein kinase 1 (tpk1b) gene encodes a receptor-like cytoplasmic kinase localized to the plasma membrane. pathogen infection, mechanical wounding, and oxidative stress induce expression of tpk1b, and reducing tpk1b gene expression through rna interference (rnai) increases tomato susceptibility to the necrotrophic fungus botrytis cinerea and to feeding by larvae of tobacco hornworm (manduca sexta) but not to the bacterial pathogen pseudomonas syringae. tpk1b rnai seedlings are also im ... | 2008 | 18599583 |
| arabidopsis mitogen-activated protein kinase kinases mkk1 and mkk2 have overlapping functions in defense signaling mediated by mekk1, mpk4, and mks1. | the arabidopsis (arabidopsis thaliana) mkk1 and mkk2 mitogen-activated protein kinase kinases have been implicated in biotic and abiotic stress responses as part of a signaling cascade including mekk1 and mpk4. here, the double loss-of-function mutant (mkk1/2) of mkk1 and mkk2 is shown to have marked phenotypes in development and disease resistance similar to those of the single mekk1 and mpk4 mutants. because mkk1 or mkk2 single mutants appear wild type, basal levels of mpk4 activity are not im ... | 2008 | 18599650 |
| a role for a menthone reductase in resistance against microbial pathogens in plants. | plants elaborate a vast array of enzymes that synthesize defensive secondary metabolites in response to pathogen attack. here, we isolated the pathogen-responsive camnr1 [menthone: (+)-(3s)-neomenthol reductase] gene, a member of the short-chain dehydrogenase/reductase (sdr) superfamily, from pepper (capsicum annuum) plants. gas chromatography-mass spectrometry analysis revealed that purified camnr1 and its ortholog atsdr1 from arabidopsis (arabidopsis thaliana) catalyze a menthone reduction wit ... | 2008 | 18599651 |
| a role for atwrky23 in feeding site establishment of plant-parasitic nematodes. | during the interaction between sedentary plant-parasitic nematodes and their host, complex morphological and physiological changes occur in the infected plant tissue, finally resulting in the establishment of a nematode feeding site. this cellular transformation is the result of altered plant gene expression most likely induced by proteins injected in the plant cell by the nematode. here, we report on the identification of a wrky transcription factor expressed during nematode infection. using bo ... | 2008 | 18599655 |
| a novel role for protein farnesylation in plant innate immunity. | plants utilize tightly regulated mechanisms to defend themselves against pathogens. initial recognition results in activation of specific resistance (r) proteins that trigger downstream immune responses, in which the signaling networks remain largely unknown. a point mutation in suppressor of npr1 constitutive1 (snc1), a resistance to peronospora parasitica4 r gene homolog, renders plants constitutively resistant to virulent pathogens. genetic suppressors of snc1 may carry mutations in genes enc ... | 2008 | 18599656 |
| clpxp proteases positively regulate alginate overexpression and mucoid conversion in pseudomonas aeruginosa. | overproduction of the exopolysaccharide alginate and conversion to a mucoid phenotype in pseudomonas aeruginosa are markers for the onset of chronic lung infection in cystic fibrosis (cf). alginate production is regulated by the extracytoplasmic function (ecf) sigma factor algu/t and the cognate anti-sigma factor muca. many clinical mucoid isolates carry loss-of-function mutations in muca. these mutations, including the most common muca22 allele, cause c-terminal truncations in muca, indicating ... | 2008 | 18599839 |
| toxic introns and parasitic intein in coxiella burnetii: legacies of a promiscuous past. | the genome of the obligate intracellular pathogen coxiella burnetii contains a large number of selfish genetic elements, including two group i introns (cbu.l1917 and cbu.l1951) and an intervening sequence that interrupts the 23s rrna gene, an intein (cbu.dnab) within dnab and 29 insertion sequences. here, we describe the ability of the intron-encoded rnas (ribozymes) to retard bacterial growth rate (toxicity) and examine the functionality and phylogenetic history of cbu.dnab. when expressed in e ... | 2008 | 18606739 |
| sphingolipid long-chain base hydroxylation is important for growth and regulation of sphingolipid content and composition in arabidopsis. | sphingolipids are structural components of endomembranes and function through their metabolites as bioactive regulators of cellular processes such as programmed cell death. a characteristic feature of plant sphingolipids is their high content of trihydroxy long-chain bases (lcbs) that are produced by the lcb c-4 hydroxylase. to determine the functional significance of trihydroxy lcbs in plants, t-dna double mutants and rna interference suppression lines were generated for the two arabidopsis tha ... | 2008 | 18612100 |
| nontemplated terminal nucleotidyltransferase activity of double-stranded rna bacteriophage phi6 rna-dependent rna polymerase. | the replication and transcription of double-stranded rna (dsrna) viruses occur within a polymerase complex particle in which the viral genome is enclosed throughout the entire life cycle of the virus. a single protein subunit in the polymerase complex is responsible for the template-dependent rna polymerization activity. the isolated polymerase subunit of the dsrna bacteriophage phi6 was previously shown to replicate and transcribe given rna molecules. in this study, we show that this enzyme als ... | 2008 | 18614640 |
| the effect of the bacterial effector protein harpin on transcriptional profile and mitochondrial proteins of arabidopsis thaliana. | here we report on the effect of the bacterial elicitor harpin from pseudomonas syringae on arabidopsis thaliana with an emphasis on transcriptional profiling and on changes of the mitochondrial proteome. interestingly, of the currently about 400 identified mitochondrial proteins, transcriptional profiling by genome-wide dna-microarray analyses revealed a total of 192 genes that showed significant changes in transcript abundance in response to the bacterial elicitor. the most dramatic changes wer ... | 2008 | 18617142 |
| chemical constituents and antimicrobial activity of medicinal plants from ghana: cassia sieberiana, haematostaphis barteri, mitragyna inermis and pseudocedrela kotschyi. | the antimicrobial activity of the sequential n-hexane, acetone and 50% aqueous methanol extracts of leaves, stem bark and roots of four species of medicinal plants, cassia sieberiana dc. (leguminosae), haematostaphis barteri hook. f. (anacardiaceae), mitragyna inermis (willd.) o. kuntze (rubiaceae) and pseudocedrela kotschyi (schweinf.) harms (meliaceae), from ghana were tested against bacillus subtilis, pseudomonas syringae and cladosporium herbarum using tlc direct-autobiographic methods. extr ... | 2008 | 18618525 |
| stabbing in the bak--an original target for avirulence genes of plant pathogens. | paradoxically, plant pathogens possess avirulence genes that render them avirulent in resistant hosts. in cell host & microbe, shan et al. (2008) show that the original role of the pseudomonas syringae avirulence genes avrpto and avrptob is to target bak1, a protein kinase important in hormone and innate immunity signaling. | 2008 | 18621005 |
| the yeast saccharomyces cerevisiae: a versatile model system for the identification and characterization of bacterial virulence proteins. | microbial pathogens utilize complex secretion systems to deliver proteins into host cells. these effector proteins target and usurp host cell processes to promote infection and cause disease. while secretion systems are conserved, each pathogen delivers its own unique set of effectors. the identification and characterization of these effector proteins has been difficult, often limited by the lack of detectable signal sequences and functional redundancy. model systems including yeast, worms, flie ... | 2008 | 18621006 |
| bacterial effectors target the common signaling partner bak1 to disrupt multiple mamp receptor-signaling complexes and impede plant immunity. | successful pathogens have evolved strategies to interfere with host immune systems. for example, the ubiquitous plant pathogen pseudomonas syringae injects two sequence-distinct effectors, avrpto and avrptob, to intercept convergent innate immune responses stimulated by multiple microbe-associated molecular patterns (mamps). however, the direct host targets and precise molecular mechanisms of bacterial effectors remain largely obscure. we show that avrpto and avrptob bind the arabidopsis recepto ... | 2008 | 18621007 |
| molecular evolution of the pi-ta gene resistant to rice blast in wild rice (oryza rufipogon). | rice blast disease resistance to the fungal pathogen magnaporthe grisea is triggered by a physical interaction between the protein products of the host r (resistance) gene, pi-ta, and the pathogen avr (avirulence) gene, avr-pita. the genotype variation and resistant/susceptible phenotype at the pi-ta locus of wild rice (oryza rufipogon), the ancestor of cultivated rice (o. sativa), was surveyed in 36 locations worldwide to study the molecular evolution and functional adaptation of the pi-ta gene ... | 2008 | 18622033 |
| roadmap to new virulence determinants in pseudomonas syringae: insights from comparative genomics and genome organization. | systematic comparison of the current repertoire of virulence-associated genes for three pseudomonas syringae strains with complete genome sequences, p. syringae pv. tomato dc3,000, p. syringae pv. phaseolicola 1448a, and p. syringae pv. syringae b728a, is prompted by recent advances in virulence factor identification in p. syringae and other bacteria. among these are genes linked to epiphytic fitness, plant- and insect-active toxins, secretion pathways, and virulence regulators, all reflected in ... | 2008 | 18624633 |
| eukaryotic translation initiation factor 5a is involved in pathogen-induced cell death and development of disease symptoms in arabidopsis. | eukaryotic translation initiation factor 5a (eif5a) is a highly conserved protein found in all eukaryotic kingdoms. this study demonstrates that plant eif5a is involved in the development of disease symptoms induced by a common necrotrophic bacterial phytopathogen. specifically, ateif5a-2, one of the three eif5a genes in arabidopsis (arabidopsis thaliana), is shown to regulate programmed cell death caused by infection with virulent pseudomonas syringae pv tomato dc3000 (pst dc3000). transgenic a ... | 2008 | 18633122 |
| root-microbe communication through protein secretion. | biotic interactions in the rhizosphere are biologically important, and although many of those interactions have been well studied, the role of secreted proteins in the cross-talk between microbes and roots has not been investigated. here, protein secretion was studied during the communication between the roots of two plants (medicago sativa and arabidopsis thaliana) and the bacterial symbiont of one of these species (sinorhizobium meliloti strain rm1021) and an opportunistic bacterial pathogen o ... | 2008 | 18635546 |
| plant immunity requires conformational changes [corrected] of npr1 via s-nitrosylation and thioredoxins. | changes in redox status have been observed during immune responses in different organisms, but the associated signaling mechanisms are poorly understood. in plants, these redox changes regulate the conformation of npr1, a master regulator of salicylic acid (sa)-mediated defense genes. npr1 is sequestered in the cytoplasm as an oligomer through intermolecular disulfide bonds. we report that s-nitrosylation of npr1 by s-nitrosoglutathione (gsno) at cysteine-156 facilitates its oligomerization, whi ... | 2008 | 18635760 |
| virus meets rnai. symposium on antiviral applications of rna interference. | 2008 | 18636088 | |
| enzymatic, immunological and phylogenetic characterization of brucella suis urease. | the sequenced genomes of the brucella spp. have two urease operons, ure-1 and ure-2, but there is evidence that only one is responsible for encoding an active urease. the present work describes the purification and the enzymatic and phylogenomic characterization of urease from brucella suis strain 1330. additionally, the urease reactivity of sera from patients diagnosed with brucellosis was examined. | 2008 | 18638408 |
| ethylene production by metabolic engineering of the yeast saccharomyces cerevisiae. | the non-ethylene producing yeast, saccharomyces cerevisiae, was transformed into an ethylene producer by introducing the ethylene forming enzyme from the plant pathogenic bacterium pseudomonas syringae. cultivation of the metabolically engineered strain was performed in well-controlled bioreactors as aerobic batch cultures with an on-line monitoring of ethylene production. the highest productivity was obtained during the respiro-fermentative growth on glucose but there was also a significant rat ... | 2008 | 18640286 |
| crystal structure of colicin m, a novel phosphatase specifically imported by escherichia coli. | colicins are cytotoxic proteins secreted by certain strains of escherichia coli. colicin m is unique among these toxins in that it acts in the periplasm and specifically inhibits murein biosynthesis by hydrolyzing the pyrophosphate linkage between bactoprenol and the murein precursor. we crystallized colicin m and determined the structure at 1.7a resolution using x-ray crystallography. the protein has a novel structure composed of three domains with distinct functions. the n-domain is a short ra ... | 2008 | 18640984 |
| genomic analysis of the role of rnase r in the turnover of pseudomonas putida mrnas. | rnase r is a 3'-5' highly processive exoribonuclease that can digest rnas with extensive secondary structure. we analyzed the global effect of eliminating rnase r on the pseudomonas putida transcriptome and the expression of the rnr gene under diverse conditions. the absence of rnase r led to increased levels of many mrnas, indicating that it plays an important role in mrna turnover. | 2008 | 18641145 |
| plant lesions promote the rapid multiplication of escherichia coli o157:h7 on postharvest lettuce. | several outbreaks of escherichia coli o157:h7 infections have been associated with minimally processed leafy vegetables in the united states. harvesting and processing cause plant tissue damage. in order to assess the role of plant tissue damage in the contamination of leafy greens with e. coli o157:h7, the effect of mechanical, physiological, and plant disease-induced lesions on the growth of this pathogen on postharvest romaine lettuce was investigated. within only 4 h after inoculation, the p ... | 2008 | 18641153 |
| overexpression of a fatty acid amide hydrolase compromises innate immunity in arabidopsis. | n-acylethanolamines are a group of lipid mediators that accumulate under a variety of neurological and pathological conditions in mammals. n-acylethanolamine signaling is terminated by the action of diverse hydrolases, among which fatty acid amide hydrolase (faah) has been well characterized. here, we show that transgenic arabidopsis lines overexpressing an atfaah are more susceptible to the bacterial pathogens pseudomonas syringae pv. tomato and p. syringae pv. maculicola. atfaah overexpressors ... | 2008 | 18643971 |
| a role for inositol hexakisphosphate in the maintenance of basal resistance to plant pathogens. | phytic acid (myo-inositol hexakisphosphate, insp6) is an important phosphate store and signal molecule in plants. however, low-phytate plants are being developed to minimize the negative health effects of dietary insp6 and pollution caused by undigested insp6 in animal waste. insp6 levels were diminished in transgenic potato plants constitutively expressing an antisense gene sequence for myo-inositol 3-phosphate synthase (ips, catalysing the first step in insp6 biosynthesis) or escherichia coli ... | 2008 | 18643983 |
| identification of likely orthologs of tobacco salicylic acid-binding protein 2 and their role in systemic acquired resistance in arabidopsis thaliana. | salicylic acid-binding protein 2 (sabp2) is essential for the establishment of systemic acquired resistance (sar) in tobacco; sabp2's methyl salicylate (mesa) esterase activity is required in healthy systemic tissues of infected plants to release the active defense phytohormone sa from mesa, which serves as a long-distance signal for sar. in the current study, we characterize a new gene family from arabidopsis thaliana encoding 18 potentially active alpha/beta fold hydrolases that share 32-57% i ... | 2008 | 18643994 |
| genetics of bacterial alginate: alginate genes distribution, organization and biosynthesis in bacteria. | bacterial alginate genes are chromosomal and fairly widespread among rrna homology group i pseudomonads and azotobacter. in both genera, the genetic pathway of alginate biosynthesis is mostly similar and the identified genes are identically organized into biosynthetic, regulatory and genetic switching clusters. in spite of these similarities,still there are transcriptional and functional variations between p. aeruginosa and a. vinelandii. in p. aeruginosa all biosynthetic genes except algc trans ... | 2007 | 18645604 |
| arabidopsis map kinase 4 regulates gene expression through transcription factor release in the nucleus. | plant and animal perception of microbes through pathogen surveillance proteins leads to map kinase signalling and the expression of defence genes. however, little is known about how plant map kinases regulate specific gene expression. we report that, in the absence of pathogens, arabidopsis map kinase 4 (mpk4) exists in nuclear complexes with the wrky33 transcription factor. this complex depends on the mpk4 substrate mks1. challenge with pseudomonas syringae or flagellin leads to the activation ... | 2008 | 18650934 |
| complete genome sequence of the n2-fixing broad host range endophyte klebsiella pneumoniae 342 and virulence predictions verified in mice. | we report here the sequencing and analysis of the genome of the nitrogen-fixing endophyte, klebsiella pneumoniae 342. although k. pneumoniae 342 is a member of the enteric bacteria, it serves as a model for studies of endophytic, plant-bacterial associations due to its efficient colonization of plant tissues (including maize and wheat, two of the most important crops in the world), while maintaining a mutualistic relationship that encompasses supplying organic nitrogen to the host plant. genomic ... | 2008 | 18654632 |
| 3-methylarginine from pseudomonas syringae pv. syringae 22d/93 suppresses the bacterial blight caused by its close relative pseudomonas syringae pv. glycinea. | the epiphyte pseudomonas syringae pv. syringae 22d/93 (pss22d) produces a toxin that strongly inhibits the growth of its relative, the plant pathogen p. syringae pv. glycinea. the inhibition can be overcome by supplementing the growth medium with the essential amino acid, l-arginine; this suggests that the toxin acts as an inhibitor of the arginine biosynthesis. the highly polar toxin was purified by bioassay-guided fractionation using ion-exchange chromatography and subsequent rp-hplc fractiona ... | 2008 | 18655083 |
| advances in and applications of proteasome inhibitors. | with the recent us food and drug administration approval of bortezomib (velcade) for the treatment of relapsed multiple myeloma, the proteasome has emerged as a new therapeutic target with diverse pathology. drug discovery programs in academia and the pharmaceutical industry have developed a range of low nanomolar synthetic and natural inhibitors of the 20s proteasome core particle that have entered human clinical trials as significant anti-cancer and anti-inflammatory leads. moreover, proteasom ... | 2008 | 18656549 |
| purification and characterization of the epoxidase catalyzing the formation of fosfomycin from pseudomonas syringae. | the final step in the biosynthesis of fosfomycin in streptomyces wedmorensis is catalyzed by ( s)-2-hydroxypropylphosphonic acid (hpp) epoxidase ( sw-hppe). a homologous enzyme from pseudomonas syringae whose encoding gene ( orf3) shares a relatively low degree of sequence homology with the corresponding sw-hppe gene has recently been isolated. this purified p. syringae protein was determined to catalyze the epoxidation of ( s)-hpp to fosfomycin and the oxidation of ( r)-hpp to 2-oxopropylphosph ... | 2008 | 18656958 |
| human gltp and mutant forms of acd11 suppress cell death in the arabidopsis acd11 mutant. | the arabidopsis acd11 mutant exhibits runaway, programmed cell death due to the loss of a putative sphingosine transfer protein (acd11) with homology to mammalian gltp. we demonstrate that transgenic expression in arabidopsis thaliana of human gltp partially suppressed the phenotype of the acd11 null mutant, resulting in delayed programmed cell death development and plant survival. surprisingly, a gltp mutant form impaired in glycolipid transfer activity also complemented the acd11 mutants. to u ... | 2008 | 18657186 |
| transcription factor myc2 is involved in priming for enhanced defense during rhizobacteria-induced systemic resistance in arabidopsis thaliana. | upon appropriate stimulation, plants can develop an enhanced capacity to express infection-induced cellular defense responses, a phenomenon known as the primed state. colonization of the roots of arabidopsis thaliana by the beneficial rhizobacterial strain pseudomonas fluorescens wcs417r primes the leaf tissue for enhanced pathogen- and insect-induced expression of jasmonate (ja)-responsive genes, resulting in an induced systemic resistance (isr) that is effective against different types of path ... | 2008 | 18657213 |
| ultraviolet radiation drives methane emissions from terrestrial plant pectins. | recent studies demonstrating an in situ formation of methane (ch(4)) within foliage and separate observations that soil-derived ch(4) can be released from the stems of trees have continued the debate about the role of vegetation in ch(4) emissions to the atmosphere. here, a study of the role of ultraviolet (uv) radiation in the formation of ch(4) and other trace gases from plant pectins in vitro and from leaves of tobacco (nicotiana tabacum) in planta is reported. plant pectins were investigated ... | 2008 | 18657215 |
| phytopathogen type iii effector weaponry and their plant targets. | phytopathogenic bacteria suppress plant innate immunity and promote pathogenesis by injecting proteins called type iii effectors into plant cells using a type iii protein secretion system. these type iii effectors use at least three strategies to alter host responses. one strategy is to alter host protein turnover, either by direct cleavage or by modulating ubiquitination and targeting the 26s proteasome. another strategy involves alteration of rna metabolism by transcriptional activation or adp ... | 2008 | 18657470 |
| the cladosporium fulvum virulence protein avr2 inhibits host proteases required for basal defense. | cladosporium fulvum (syn. passalora fulva) is a biotrophic fungal pathogen that causes leaf mold of tomato (solanum lycopersicum). during growth in the apoplast, the fungus establishes disease by secreting effector proteins, 10 of which have been characterized. we have previously shown that the avr2 effector interacts with the apoplastic tomato cys protease rcr3, which is required for cf-2-mediated immunity. we now show that avr2 is a genuine virulence factor of c. fulvum. heterologous expressio ... | 2008 | 18660430 |
| xopd sumo protease affects host transcription, promotes pathogen growth, and delays symptom development in xanthomonas-infected tomato leaves. | we demonstrate that xopd, a type iii effector from xanthomonas campestris pathovar vesicatoria (xcv), suppresses symptom production during the late stages of infection in susceptible tomato (solanum lycopersicum) leaves. xopd-dependent delay of tissue degeneration correlates with reduced chlorophyll loss, reduced salicylic acid levels, and changes in the mrna abundance of senescence- and defense-associated genes despite high pathogen titers. subsequent structure-function analyses led to the disc ... | 2008 | 18664616 |
| synonymous and nonsynonymous polymorphisms versus divergences in bacterial genomes. | comparison of the ratio of nonsynonymous to synonymous polymorphisms within species with the ratio of nonsynonymous to synonymous substitutions between species has been widely used as a supposed indicator of positive darwinian selection, with the ratio of these 2 ratios being designated as a neutrality index (ni). comparison of genome-wide polymorphism within 12 species of bacteria with divergence from an outgroup species showed substantial differences in ni among taxa. a low level of nonsynonym ... | 2008 | 18667439 |
| cloning, expression, and characterization of a new phytase from the phytopathogenic bacterium pectobacterium wasabiae dsmz 18074. | the soft rot bacterium pectobacterium wasabiae is an economically important pathogen of many crops. a new phytase gene, appa, was cloned from p. wasabiae by degenerate pcr and tail-pcr. the open reading frame of appa consisted of 1,302 bp encoding 433 amino acid residues, including 27 residues of a putative signal peptide. the mature protein had a molecular mass of 45 kda and a theoretical pi of 5.5. the amino acid sequence contained the conserved active site residues rhgxrxp and hdtn of typical ... | 2008 | 18667849 |
| architectures and biogenesis of non-flagellar protein appendages in gram-negative bacteria. | bacteria commonly expose non-flagellar proteinaceous appendages on their outer surfaces. these extracellular structures, called pill or fimbriae, are employed in attachment and invasion, biofilm formation, cell motility or protein and dna transport across membranes. over the past 15 years, the power of molecular and structural techniques has revolutionalized our understanding of the biogenesis, structure, function and mode of action of these bacterial organelles. here, we review the five known c ... | 2008 | 18668121 |
| cycloaspeptide a and pseurotin a from the endophytic fungus penicillium janczewskii. | penicillium janczewskii k. m. zalessky was isolated as an endophytic fungus from the phloem of the chilean gymnosperm prumnopitys andina. when grown in liquid yeast extract-malt extract-glucose broth, the fungus produced two main secondary metabolites. the compounds were for the first time isolated from this species and identified by spectroscopic methods as pseurotin a and cycloaspeptide a. this is the first report on the production of cyclic peptides by endophytic fungi from chilean gymnosperm ... | 2008 | 18669024 |
| singlet oxygen is the major reactive oxygen species involved in photooxidative damage to plants. | reactive oxygen species act as signaling molecules but can also directly provoke cellular damage by rapidly oxidizing cellular components, including lipids. we developed a high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry-based quantitative method that allowed us to discriminate between free radical (type i)- and singlet oxygen ((1)o(2); type ii)-mediated lipid peroxidation (lpo) signatures by using hydroxy fatty acids as specific reporters. using this metho ... | 2008 | 18676660 |
| involvement of the pepper antimicrobial protein caamp1 gene in broad spectrum disease resistance. | pathogen-inducible antimicrobial defense-related proteins have emerged as key antibiotic peptides and enzymes involved in disease resistance in plants. a novel antimicrobial protein gene, caamp1 (for capsicum annuum antimicrobial protein1), was isolated from pepper (c. annuum) leaves infected with xanthomonas campestris pv vesicatoria. expression of the caamp1 gene was strongly induced in pepper leaves not only during pathogen infection but also after exposure to abiotic elicitors. the purified ... | 2008 | 18676663 |
| characterization of chromosomal regions conserved in yersinia pseudotuberculosis and lost by yersinia pestis. | the transformation of the enteropathogenic bacterium yersinia pseudotuberculosis into the plague bacillus, yersinia pestis, has been accompanied by extensive genetic loss. this study focused on chromosomal regions conserved in y. pseudotuberculosis and lost during its transformation into y. pestis. an extensive pcr screening of 78 strains of the two species identified five regions (r1 to r5) and four open reading frames (orfs; orf1 to orf4) that were conserved in y. pseudotuberculosis and absent ... | 2008 | 18678673 |
| secretory pathways in plant immune responses. | 2008 | 18678749 | |
| the vibrio harveyi master quorum-sensing regulator, luxr, a tetr-type protein is both an activator and a repressor: dna recognition and binding specificity at target promoters. | quorum sensing is the process of cell-to-cell communication by which bacteria communicate via secreted signal molecules called autoinducers. as cell population density increases, the accumulation of autoinducers leads to co-ordinated changes in gene expression across the bacterial community. the marine bacterium, vibrio harveyi, uses three autoinducers to achieve intra-species, intra-genera and inter-species cell-cell communication. the detection of these autoinducers ultimately leads to the pro ... | 2008 | 18681939 |
| mgdd: mycobacterium tuberculosis genome divergence database. | variation in genomes among different closely-related organisms can be linked to phenotypic differences. a number of mechanisms, such as replication error, repeat expansion and contraction, recombination and transposition can contribute to genomic differences. these processes lead to generation of snps, different types of repeat-based and transposons or is-element-based polymorphisms, inversions and duplications and changes in synteny. a database of all the variations in a group of organisms is n ... | 2008 | 18681951 |
| innate immunity signaling: cytosolic ca2+ elevation is linked to downstream nitric oxide generation through the action of calmodulin or a calmodulin-like protein. | ca(2+) rise and nitric oxide (no) generation are essential early steps in plant innate immunity and initiate the hypersensitive response (hr) to avirulent pathogens. previous work from this laboratory has demonstrated that a loss-of-function mutation of an arabidopsis (arabidopsis thaliana) plasma membrane ca(2+)-permeable inwardly conducting ion channel impairs hr and that this phenotype could be rescued by the application of a no donor. at present, the mechanism linking cytosolic ca(2+) rise t ... | 2008 | 18689446 |
| robustness promotes evolvability of thermotolerance in an rna virus. | the ability for an evolving population to adapt to a novel environment is achieved through a balance of robustness and evolvability. robustness is the invariance of phenotype in the face of perturbation and evolvability is the capacity to adapt in response to selection. genetic robustness has been posited, depending on the underlying mechanism, to either decrease the efficacy of selection, or increase the possibility of future adaptation. however, the true effect of genetic robustness on evolvab ... | 2008 | 18694497 |
| identification and functional characterization of gene components of type vi secretion system in bacterial genomes. | a new secretion system, called the type vi secretion system (t6ss), was recently reported in vibrio cholerae, pseudomonas aeruginosa and burkholderia mallei. a total of 18 genes have been identified to be belonging to this secretion system in v. cholerae. here we attempt to identify presence of t6ss in other bacterial genomes. this includes identification of orthologous sequences, conserved motifs, domains, families, 3d folds, genomic islands containing t6ss components, phylogenetic profiles and ... | 2008 | 18698408 |
| type iii secretion system genes of dickeya dadantii 3937 are induced by plant phenolic acids. | dickeya dadantii is a broad-host range phytopathogen. d. dadantii 3937 (ech3937) possesses a type iii secretion system (t3ss), a major virulence factor secretion system in many gram-negative pathogens of plants and animals. in ech3937, the t3ss is regulated by two major regulatory pathways, hrpx/hrpy-hrps-hrpl and gacs/gaca-rsmb-rsma pathways. although the plant apoplast environment, low ph, low temperature, and absence of complex nitrogen sources in media have been associated with the induction ... | 2008 | 18698421 |
| antimicrobial activity of gamma-thionin-like soybean se60 in e. coli and tobacco plants. | the se60, a low molecular weight, sulfur-rich protein in soybean, is known to be homologous to wheat gamma-purothionin. to elucidate the functional role of se60, we expressed se60 cdna in escherichia coli and in tobacco plants. a single protein band was detected by sds-polyacrylamide gel electrophoresis (sds-page) after anti-flag affinity purification of the protein from transformed e. coli. while the control e. coli cells harboring pflag-1 showed standard growth with isopropyl beta-d-1-thiogala ... | 2008 | 18700134 |
| amino acid sequence of bacterial microbe-associated molecular pattern flg22 is required for virulence. | flagellin proteins derived from pseudomonas syringae pv. tabaci 6605 and flg22pa (qrlstgsrinsakddaaglqia), one of the microbe-associated molecular patterns (mamp) in bacterial flagellin, induce cell death and growth inhibition in arabidopsis thaliana. to examine the importance of aspartic acid (d) at position 43 from the n-terminus of a flagellin in its elicitor activity, d43 was replaced with valine (v) and alanine (a) in p. syringae pv. tabaci flagellin and flg22pta. the abilities of flagellin ... | 2008 | 18700821 |
| expression of a class 1 hemoglobin gene and production of nitric oxide in response to symbiotic and pathogenic bacteria in lotus japonicus. | symbiotic nitrogen fixation by the collaboration between leguminous plants and rhizobia is an important system in the global nitrogen cycle, and some molecular aspects during the early stage of host-symbiont recognition have been revealed. to understand the responses of a host plant against various bacteria, we examined expression of hemoglobin (hb) genes and production of nitric oxide (no) in lotus japonicus after inoculation with rhizobia or plant pathogens. when the symbiotic rhizobium mesorh ... | 2008 | 18700822 |
| the plant innate immunity response in stomatal guard cells invokes g-protein-dependent ion channel regulation. | stomata in the epidermis of terrestrial plants are important for co2 absorption and transpirational water loss, and are also potential points of entry for pathogens. stomatal opening and closure are controlled by distinct mechanisms. arabidopsis stomata have been shown to close in response to bacteria and pathogen-associated molecular patterns (pamps) as part of pamp-triggered immunity (pti). here we show that flg22, a pamp derived from bacterial flagellin, also inhibits light-induced stomatal o ... | 2008 | 18702674 |
| focal accumulation of defences at sites of fungal pathogen attack. | plants resist attack by haustorium-forming biotrophic and hemi-biotrophic fungi through fortification of the cell wall to prevent penetration through the wall and the subsequent establishment of haustorial feeding structures by the fungus. while the existence of cell wall-based defences has been known for many years, only recently have the molecular components contributing to such defences been identified. forward genetic screens identified arabidopsis mutants impaired in penetration resistance ... | 2008 | 18703493 |
| suppression of the microrna pathway by bacterial effector proteins. | plants and animals sense pathogen-associated molecular patterns (pamps) and in turn differentially regulate a subset of micrornas (mirnas). however, the extent to which the mirna pathway contributes to innate immunity remains unknown. here, we show that mirna-deficient mutants of arabidopsis partly restore growth of a type iii secretion-defective mutant of pseudomonas syringae. these mutants also sustained growth of nonpathogenic pseudomonas fluorescens and escherichia coli strains, implicating ... | 2008 | 18703740 |
| role of a xyloglucan-specific endo-beta-1,4-glucanase inhibitor in the interactions of nicotiana benthamiana with colletotrichum destructivum, c. orbiculare or pseudomonas syringae pv. tabaci. | a xyloglucan-specific endo-beta-1,4-glucanase inhibitor cdna, nbxegip1, was amplified from diseased leaves of nicotiana benthamiana. the sequence was similar to the tomato xyloglucan-specific endo-beta-1,4-glucanase inhibitor (xegip) and tobacco nectarin iv genes that have been described as binding and inactivating fungal family 12 xyloglucan-specific endo-beta-1,4-glucanases. expression of nbxegip1 was not detected in healthy leaves, but the gene was induced during the later stages of infection ... | 2008 | 18705851 |
| extraction of high-quality bacterial rna from infected leaf tissue for bacterial in planta gene expression analysis by multiplexed fluorescent northern hybridization. | plant pathogenic bacteria possess a large number of genes that allow them to grow and cause disease on plants. in planta gene expression analysis is important to understand the impact of these genes on bacterial virulence. a new mrna-based approach using multiplexed northern hybridization was developed. high-quality bacterial and plant total rna was successfully isolated from leaf tissue infiltrated with pseudomonas syringae. the procedure employs a new extraction buffer formulation containing g ... | 2008 | 18705854 |
| high-throughput in planta expression screening identifies an adp-ribosylation factor (arf1) involved in non-host resistance and r gene-mediated resistance. | to identify positive regulators of cell death in plants, we performed a high-throughput screening, employing potato virus x-based overexpression in planta of a cdna library derived from paraquat-treated nicotiana benthamiana leaves. the screening of 30,000 cdna clones enabled the identification of an adp-ribosylation factor 1 (arf1) that induces cell death when overexpressed in n. benthamiana. overexpression of the guanosine diphosphate (gdp)-locked mutant of arf1 did not trigger cell death, sug ... | 2008 | 18705881 |