Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
crystal structure of a putative quorum sensing-regulated protein (pa3611) from the pseudomonas-specific duf4146 family.pseudomonas aeruginosa is an opportunistic pathogen commonly found in humans and other organisms and is an important cause of infection especially in patients with compromised immune defense mechanisms. the pa3611 gene of p. aeruginosa pao1 encodes a secreted protein of unknown function, which has been recently classified into a small pseudomonas-specific protein family called duf4146. as part of our effort to extend structural coverage of novel protein space and provide a structure-based functi ...201324174223
the genome of pseudomonas fluorescens strain r124 demonstrates phenotypic adaptation to the mineral environment.microbial adaptation to environmental conditions is a complex process, including acquisition of positive traits through horizontal gene transfer or the modification of existing genes through duplication and/or mutation. in this study, we examined the adaptation of a pseudomonas fluorescens isolate (r124) from the nutrient-limited mineral environment of a silica cave in comparison with p. fluorescens isolates from surface soil and the rhizosphere. examination of metal homeostasis gene pathways de ...201323995634
two-way plant mediated interactions between root-associated microbes and insects: from ecology to mechanisms.plants are members of complex communities and function as a link between above- and below-ground organisms. associations between plants and soil-borne microbes commonly occur and have often been found beneficial for plant fitness. root-associated microbes may trigger physiological changes in the host plant that influence interactions between plants and aboveground insects at several trophic levels. aboveground, plants are under continuous attack by insect herbivores and mount multiple responses ...201324167508
arabidopsis tnl-wrky domain receptor rrs1 contributes to temperature-conditioned rps4 auto-immunity.in plant effector-triggered immunity (eti), intracellular nucleotide binding-leucine rich repeat (nlr) receptors are activated by specific pathogen effectors. the arabidopsis tir (toll-interleukin-1 receptor domain)-nlr (denoted tnl) gene pair, rps4 and rrs1, confers resistance to pseudomonas syringae pv tomato (pst) strain dc3000 expressing the type iii-secreted effector, avrrps4. nuclear accumulation of avrrps4, rps4, and the tnl resistance regulator eds1 is necessary for eti. rrs1 possesses a ...201324146667
identification and molecular characterization of ysal (ye3555): a novel negative regulator of ysan atpase in type three secretion system of enteropathogenic bacteria yersinia enterocolitica.type three secretion (t3s) atpases are involved in delivery of virulent factors from bacteria to their hosts (through injectisome) in an energy (atp) dependent manner during pathogenesis. the activities of these atpases are tightly controlled by their specific regulators. in yersinia enterocolitica, ysan was predicted as a putative atpase of the ysa-ysp type three secretion system (t3ss) based on sequence similarity with other t3s atpases. however detailed study and characterization of ysan and ...201324124464
molecular basis of active copper resistance mechanisms in gram-negative bacteria.copper is a metallic element that is crucial for cell metabolism; however, in extended concentrations, it is toxic for all living organisms. the dual nature of copper has forced organisms, including bacteria, to keep a tight hold on cellular copper content. this challenge has led to the evolution of complex mechanisms that on one hand enable them to deliver the essential element and on the other to protect cells against its toxicity. such mechanisms have been found in both eukaryotic and prokary ...201324072389
a genomic redefinition of pseudomonas avellanae species.the circumscription of bacterial species is a complex task. so far, dna-dna hybridization (ddh), 16s rrna gene sequencing, and multiocus sequence typing analysis (mlsa) are currently the preferred techniques for their genetic determination. however, the average nucleotide identity (ani) analysis of conserved and shared genes between two bacterial strains based on the pair-wise genome comparisons, with support of the tetranucleotide frequency correlation coefficients (tetra) value, has recently b ...201324086635
growth of arabidopsis seedlings on high fungal doses of piriformospora indica has little effect on plant performance, stress, and defense gene expression in spite of elevated jasmonic acid and jasmonic acid-isoleucine levels in the roots.the endophytic fungus piriformospora indica colonizes the roots of many plant species including arabidopsis and promotes their performance, biomass, and seed production as well as resistance against biotic and abiotic stress. imbalances in the symbiotic interaction such as uncontrolled fungal growth result in the loss of benefits for the plants and activation of defense responses against the microbe. we exposed arabidopsis seedlings to a dense hyphal lawn of p. indica. the seedlings continue to ...201324047645
luxr- and luxi-type quorum-sensing circuits are prevalent in members of the populus deltoides microbiome.we are interested in the root microbiome of the fast-growing eastern cottonwood tree, populus deltoides. there is a large bank of bacterial isolates from p. deltoides, and there are 44 draft genomes of bacterial endophyte and rhizosphere isolates. as a first step in efforts to understand the roles of bacterial communication and plant-bacterial signaling in p. deltoides, we focused on the prevalence of acyl-homoserine lactone (ahl) quorum-sensing-signal production and reception in members of the ...201323851092
pa506, a conjugative plasmid of the plant epiphyte pseudomonas fluorescens a506.conjugative plasmids are known to facilitate the acquisition and dispersal of genes contributing to the fitness of pseudomonas spp. here, we report the characterization of pa506, the 57-kb conjugative plasmid of pseudomonas fluorescens a506, a plant epiphyte used in the united states for the biological control of fire blight disease of pear and apple. twenty-nine of the 67 open reading frames (orfs) of pa506 have putative functions in conjugation, including a type iv secretion system related to ...201323811504
identification of another module involved in the horizontal transfer of the haemophilus genomic island icehin1056.a significant part of horizontal gene transfer is facilitated by genomic islands. haemophilus influenzae genomic island icehin1056 is an archetype of a genomic island that accounts for pandemic spread of antibiotics resistance. icehin1056 has modular structure and harbors modules involved in type iv secretion and integration. previous studies have shown that icehin1056 encodes a functional type iv secretion system; however, other modules have not been characterized yet. here we show that the mod ...201323764277
genetic detection of pseudomonas spp. in commercial amazonian fish.brazilian freshwater fish caught from large drainages like the river amazon represent a million ton market in expansion, which is of enormous importance for export to other continents as exotic seafood. a guarantee of bacteriological safety is required for international exports that comprise a set of different bacteria but not any pseudomonas. however, diarrhoea, infections and even septicaemia caused by some pseudomonas species have been reported, especially in immune-depressed patients. in thi ...201324065035
synthetic biology of cyanobacteria: unique challenges and opportunities.photosynthetic organisms, and especially cyanobacteria, hold great promise as sources of renewably-produced fuels, bulk and specialty chemicals, and nutritional products. synthetic biology tools can help unlock cyanobacteria's potential for these functions, but unfortunately tool development for these organisms has lagged behind that for s. cerevisiae and e. coli. while these organisms may in many cases be more difficult to work with as "chassis" strains for synthetic biology than certain hetero ...201324009604
small molecules mediate bacterial farming by social amoebae. 201323975931
complete sequence of poz176, a 500-kilobase incp-2 plasmid encoding imp-9-mediated carbapenem resistance, from outbreak isolate pseudomonas aeruginosa 96.pseudomonas aeruginosa 96 (pa96) was isolated during a multicenter surveillance study in guangzhou, china, in 2000. whole-genome sequencing of this outbreak strain facilitated analysis of its incp-2 carbapenem-resistant plasmid, poz176. the plasmid had a length of 500,839 bp and an average percent g+c content of 57%. of the 618 predicted open reading frames, 65% encode hypothetical proteins. the poz176 backbone is not closely related to any plasmids thus far sequenced, but some similarity to pqb ...201323716048
investigating the beneficial traits of trichoderma hamatum gd12 for sustainable agriculture-insights from genomics.trichoderma hamatum strain gd12 is unique in that it can promote plant growth, activate biocontrol against pre- and post-emergence soil pathogens and can induce systemic resistance to foliar pathogens. this study extends previous work in lettuce to demonstrate that gd12 can confer beneficial agronomic traits to other plants, providing examples of plant growth promotion in the model dicot, arabidopsis thaliana and induced foliar resistance to magnaporthe oryzae in the model monocot rice. we furth ...201323908658
a bacterial symbiont is converted from an inedible producer of beneficial molecules into food by a single mutation in the gaca gene.stable multipartite mutualistic associations require that all partners benefit. we show that a single mutational step is sufficient to turn a symbiotic bacterium from an inedible but host-beneficial secondary metabolite producer into a host food source. the bacteria's host is a "farmer" clone of the social amoeba dictyostelium discoideum that carries and disperses bacteria during its spore stage. associated with the farmer are two strains of pseudomonas fluorescens, only one of which serves as a ...201323898207
mycorrhiza-induced resistance: more than the sum of its parts?plants can develop an enhanced defensive capacity in response to infection by arbuscular mycorrhizal fungi (amf). this 'mycorrhiza-induced resistance' (mir) provides systemic protection against a wide range of attackers and shares characteristics with systemic acquired resistance (sar) after pathogen infection and induced systemic resistance (isr) following root colonisation by non-pathogenic rhizobacteria. it is commonly assumed that fungal stimulation of the plant immune system is solely respo ...201323871659
plant growth in arabidopsis is assisted by compost soil-derived microbial communities.plants in natural and agricultural environments are continuously exposed to a plethora of diverse microorganisms resulting in microbial colonization of roots and the rhizosphere. this process is believed to be accompanied by an intricate network of ongoing simultaneous interactions. in this study, we examined arabidopsis thaliana roots and shoots in the presence or absence of whole microbial communities extracted from compost soil. the results show a clear growth promoting effect on arabidopsis ...201323847639
a review on phytochemistry and ethnopharmacological aspects of genus calendula.this review includes 84 references on the genus calendula (asteraceae) and comprises ethnopharmacology, morphology and microscopy, phytoconstituents, pharmacological reports, clinical studies and toxicology of the prominent species of calendula. triterpene alcohols, triterpene saponins, flavonoids, carotenoids and polysaccharides constitute major classes of phytoconstituents of the genus. a few species of this genus have medicinal value, among these calendula officinalis linn., has been traditio ...201324347926
dechlorination of chloral hydrate is influenced by the biofilm adhesin protein lapa in pseudomonas putida lf54.lapa is the largest surface adhesion protein of pseudomonas putida that initiates biofilm formation. here, by using transposon insertion mutagenesis and a conditional lapa mutant, we demonstrate for the first time that lapa influences chloral hydrate (ch) dechlorination in p. putida lf54.201323603683
structural and functional characterization of pseudomonas aeruginosa algx: role of algx in alginate acetylation.the exopolysaccharide alginate, produced by mucoid pseudomonas aeruginosa in the lungs of cystic fibrosis patients, undergoes two different chemical modifications as it is synthesized that alter the properties of the polymer and hence the biofilm. one modification, acetylation, causes the cells in the biofilm to adhere better to lung epithelium, form microcolonies, and resist the effects of the host immune system and/or antibiotics. alginate biosynthesis requires 12 proteins encoded by the algd ...201323779107
phytoplasma-responsive micrornas modulate hormonal, nutritional, and stress signalling pathways in mexican lime trees.witches' broom disease of mexican lime (citrus aurantifolia l.), which is associated to the phytoplasma 'candidatus phytoplasma aurantifolia', is a devastating disease that results in significant economic losses. plants adapt to biotic stresses by regulating gene expression at the transcriptional and post-transcriptional levels. micrornas (mirnas) are a recently identified family of molecules that regulate plant responses to environmental stresses through post-transcriptional gene silencing.201323824690
effect of gaba, a bacterial metabolite, on pseudomonas fluorescens surface properties and cytotoxicity.different bacterial species and, particularly pseudomonas fluorescens, can produce gamma-aminobutyric acid (gaba) and express gaba-binding proteins. in this study, we investigated the effect of gaba on the virulence and biofilm formation activity of different strains of p. fluorescens. exposure of a psychotropic strain of p. fluorescens (mf37) to gaba (10-5 m) increased its necrotic-like activity on eukaryotic (glial) cells, but reduced its apoptotic effect. conversely, muscimol and bicuculline, ...201323743829
combining hexanoic acid plant priming with bacillus thuringiensis insecticidal activity against colorado potato beetle.interaction between insect herbivores and host plants can be modulated by endogenous and exogenous compounds present in the source of food and might be successfully exploited in colorado potato beetle (cpb) pest management. feeding tests with cpb larvae reared on three solanaceous plants (potato, eggplant and tomato) resulted in variable larval growth rates and differential susceptibility to bacillus thuringiensis cry3aa toxin as a function of the host plant. an inverse correlation with toxicity ...201323743826
the type iii secreted effector dspe is required early in solanum tuberosum leaf infection by pectobacterium carotovorum to cause cell death, and requires wx(3-6)d/e motifs.pectobacterium species are enterobacterial plant-pathogens that cause soft rot disease in diverse plant species. unlike hemi-biotrophic plant pathogenic bacteria, the type iii secretion system (t3ss) of pectobacterium carotovorum subsp. carotovorum (p. carotovorum) appears to secrete only one effector protein, dspe. previously, we found that the t3ss regulator hrpl and the effector dspe are required for p. carotovorum pathogenesis on leaves. here, we identified genes up-regulated by hrpl, visual ...201323755246
disease resistance or growth: the role of plant hormones in balancing immune responses and fitness costs.plant growth and response to environmental cues are largely governed by phytohormones. the plant hormones ethylene, jasmonic acid, and salicylic acid (sa) play a central role in the regulation of plant immune responses. in addition, other plant hormones, such as auxins, abscisic acid (aba), cytokinins, gibberellins, and brassinosteroids, that have been thoroughly described to regulate plant development and growth, have recently emerged as key regulators of plant immunity. plant hormones interact ...201323745126
pseudomonas fluorescens sbw25 produces furanomycin, a non-proteinogenic amino acid with selective antimicrobial properties.pseudomonas fluorescens sbw25 has been extensively studied because of its plant growth promoting properties and potential as a biocontrol agent. the genome of sbw25 has been sequenced, and among sequenced strains of pseudomonads, sbw25 appears to be most closely related to p. fluorescens wh6. in the authors' laboratories, wh6 was previously shown to produce and secrete 4-formylaminooxyvinylglycine (fvg), a non-proteinogenic amino acid with selective herbicidal and antimicrobial activity. althoug ...201323688329
genome sequences of pseudomonas spp. isolated from cereal crops.compared to those of dicot-infecting bacteria, the available genome sequences of bacteria that infect wheat and barley are limited. herein, we report the draft genome sequences of four pseudomonads originally isolated from these cereals. these genome sequences provide a useful resource for comparative analyses within the genus and for cross-kingdom analyses of plant pathogenesis.201323661484
effect of tannic acid on the transcriptome of the soil bacterium pseudomonas protegens pf-5.tannins are a diverse group of plant-produced, polyphenolic compounds with metal-chelating and antimicrobial properties that are prevalent in many soils. using transcriptomics, we determined that tannic acid, a form of hydrolysable tannin, broadly affects the expression of genes involved in iron and zinc homeostases, sulfur metabolism, biofilm formation, motility, and secondary metabolite biosynthesis in the soil- and rhizosphere-inhabiting bacterium pseudomonas protegens pf-5.201323435890
comparative genome analysis of burkholderia phytofirmans psjn reveals a wide spectrum of endophytic lifestyles based on interaction strategies with host plants.burkholderia phytofirmans psjn is a naturally occurring plant-associated bacterial endophyte that effectively colonizes a wide range of plants and stimulates their growth and vitality. here we analyze whole genomes, of psjn and of eight other endophytic bacteria. this study illustrates that a wide spectrum of endophytic life styles exists. although we postulate the existence of typical endophytic traits, no unique gene cluster could be exclusively linked to the endophytic lifestyle. furthermore, ...201323641251
bioactive molecules in soil ecosystems: masters of the underground.complex biological and ecological processes occur in the rhizosphere through ecosystem-level interactions between roots, microorganisms and soil fauna. over the past decade, studies of the rhizosphere have revealed that when roots, microorganisms and soil fauna physically contact one another, bioactive molecular exchanges often mediate these interactions as intercellular signal, which prepare the partners for successful interactions. despite the importance of bioactive molecules in sustainable a ...201323615474
comparative genomic analysis of four representative plant growth-promoting rhizobacteria in pseudomonas.some pseudomonas strains function as predominant plant growth-promoting rhizobacteria (pgpr). within this group, pseudomonas chlororaphis and pseudomonas fluorescens are non-pathogenic biocontrol agents, and some pseudomonas aeruginosa and pseudomonas stutzeri strains are pgpr. p. chlororaphis gp72 is a plant growth-promoting rhizobacterium with a fully sequenced genome. we conducted a genomic analysis comparing gp72 with three other pseudomonad pgpr: p. fluorescens pf-5, p. aeruginosa m18, and ...201323607266
pattern-triggered immunity suppresses programmed cell death triggered by fumonisin b1.programmed cell death (pcd) is a crucial process for plant innate immunity and development. in plant innate immunity, pcd is believed to prevent the spread of pathogens from the infection site. although proper control of pcd is important for plant fitness, we have limited understanding of the molecular mechanisms regulating plant pcd. plant innate immunity triggered by recognition of effectors (effector-triggered immunity, eti) is often associated with pcd. however pattern-triggered immunity (pt ...201323560104
comparative genomics of multiple strains of pseudomonas cannabina pv. alisalensis, a potential model pathogen of both monocots and dicots.comparative genomics of closely related pathogens that differ in host range can provide insights into mechanisms of host-pathogen interactions and host adaptation. furthermore, sequencing of multiple strains with the same host range reveals information concerning pathogen diversity and the molecular basis of virulence. here we present a comparative analysis of draft genome sequences for four strains of pseudomonas cannabina pathovar alisalensis (pcal), which is pathogenic on a range of monocotyl ...201323555661
resistance of arabidopsis thaliana to the green peach aphid, myzus persicae, involves camalexin and is regulated by micrornas.· small rnas play important roles in resistance to plant viruses and the complex responses against pathogens and leaf-chewing insects. · we investigated whether small rna pathways are involved in arabidopsis resistance against a phloem-feeding insect, the green peach aphid (myzus persicae). we used a 2-wk fecundity assay to assess aphid performance on arabidopsis rna silencing and defence pathway mutants. quantitative real-time polymerase chain reaction was used to monitor the transcriptional ac ...201323528052
structural determinants for activity and specificity of the bacterial toxin llpa.lectin-like bacteriotoxic proteins, identified in several plant-associated bacteria, are able to selectively kill closely related species, including several phytopathogens, such as pseudomonas syringae and xanthomonas species, but so far their mode of action remains unrevealed. the crystal structure of llpabw, the prototype lectin-like bacteriocin from pseudomonas putida, reveals an architecture of two monocot mannose-binding lectin (mmbl) domains and a c-terminal β-hairpin extension. the c-term ...201323468636
pseudomonas fluorescens nzi7 repels grazing by c. elegans, a natural predator.the bacteriovorous nematode caenorhabditis elegans has been used to investigate many aspects of animal biology, including interactions with pathogenic bacteria. however, studies examining c. elegans interactions with bacteria isolated from environments in which it is found naturally are relatively scarce. c. elegans is frequently associated with cultivation of the edible mushroom agaricus bisporus, and has been reported to increase the severity of bacterial blotch of mushrooms, a disease caused ...201323426012
family-specific degenerate primer design: a tool to design consensus degenerated oligonucleotides.designing degenerate pcr primers for templates of unknown nucleotide sequence may be a very difficult task. in this paper, we present a new method to design degenerate primers, implemented in family-specific degenerate primer design (fas-dpd) computer software, for which the starting point is a multiple alignment of related amino acids or nucleotide sequences. to assess their efficiency, four different genome collections were used, covering a wide range of genomic lengths: arenavirus (10 × 10(4) ...201323533783
from the root to the stem: interaction between the biocontrol root endophyte pseudomonas fluorescens picf7 and the pathogen pseudomonas savastanoi ncppb 3335 in olive knots.olive knot disease, caused by pseudomonas savastanoi pv. savastanoi, is one of the most important biotic constraints for olive cultivation. pseudomonas fluorescens picf7, a natural colonizer of olive roots and effective biological control agent (bca) against verticillium wilt of olive, was examined as potential bca against olive knot disease. bioassays using in vitro-propagated olive plants were carried out to assess whether strain picf7 controlled knot development either when co-inoculated with ...201323425069
bean common bacterial blight: pathogen epiphytic life and effect of irrigation practices.in recent years, bean common bacterial blight (cbb) caused by xanthomonas axonopodis pv. phaseoli (xap) has caused serious yield losses in several countries. cbb is considered mainly a foliar disease in which symptoms initially appear as small water-soaked spots that then enlarge and become necrotic and usually bordered by a chlorotic zone. xap epiphytic population community has a critical role in the development of the disease and subsequent epidemics. the epiphytic population of xap in the fie ...201323539532
analysis of the small rna p16/rgsa in the plant pathogen pseudomonas syringae pv. tomato strain dc3000.bacteria contain small non-coding rnas (ncrnas) that are responsible for altering transcription, translation or mrna stability. ncrnas are important because they regulate virulence factors and susceptibility to various stresses. here, the regulation of a recently described ncrna of pseudomonas syringae pv. tomato dc3000, p16, was investigated. we determined that rpos regulates the expression of p16. we found that deletion of p16 results in increased sensitivity to hydrogen peroxide compared to t ...201323258266
crcz and crcx regulate carbon source utilization in pseudomonas syringae pathovar tomato strain dc3000.small non-coding rnas (ncrnas) are important components of many regulatory pathways in bacteria and play key roles in regulating factors important for virulence. carbon catabolite repression control is modulated by small rnas (crcz or crcz and crcy) in pseudomonas aeruginosa and pseudomonas putida. in this study, we demonstrate that expression of crcz and crcx (formerly designated psr1 and psr2, respectively) is dependent upon rpon together with the two-component system cbrab, and is influenced ...201323353577
recruitment and rearrangement of three different genetic determinants into a conjugative plasmid increase copper resistance in pseudomonas syringae.we describe the genetic organization of a copper-resistant plasmid containing copg and cuscba genes in the plant pathogen pseudomonas syringae. chromosomal variants of czccba and a plasmid variant of cuscba were present in different p. syringae pathovar strains. transformation of the copper-sensitive pseudomonas syringae pv. syringae ff5 strain with copg or cuscba conferred copper resistance, and quantitative real-time pcr (qrt-pcr) experiments confirmed their induction by copper.201323183969
root exudation of phytochemicals in arabidopsis follows specific patterns that are developmentally programmed and correlate with soil microbial functions.plant roots constantly secrete compounds into the soil to interact with neighboring organisms presumably to gain certain functional advantages at different stages of development. accordingly, it has been hypothesized that the phytochemical composition present in the root exudates changes over the course of the lifespan of a plant. here, root exudates of in vitro grown arabidopsis plants were collected at different developmental stages and analyzed using gc-ms. principle component analysis reveal ...201323383346
the metabolic interplay between plants and phytopathogens.plant diseases caused by pathogenic bacteria or fungi cause major economic damage every year and destroy crop yields that could feed millions of people. only by a thorough understanding of the interaction between plants and phytopathogens can we hope to develop strategies to avoid or treat the outbreak of large-scale crop pests. here, we studied the interaction of plant-pathogen pairs at the metabolic level. we selected five plant-pathogen pairs, for which both genomes were fully sequenced, and ...201324957887
exploiting quorum sensing to confuse bacterial pathogens.cell-cell communication, or quorum sensing, is a widespread phenomenon in bacteria that is used to coordinate gene expression among local populations. its use by bacterial pathogens to regulate genes that promote invasion, defense, and spread has been particularly well documented. with the ongoing emergence of antibiotic-resistant pathogens, there is a current need for development of alternative therapeutic strategies. an antivirulence approach by which quorum sensing is impeded has caught on as ...201323471618
a tale of two machines: a review of the blast meeting, tucson, az, 20-24 january 2013.since its inception, bacterial locomotion and signal transduction (blast) meetings have been the place to exchange and share the latest developments in the field of bacterial signal transduction and motility. at the 12th blast meeting, held last january in tucson, az, researchers from all over the world met to report and discuss progress in diverse aspects of the field. the majority of these advances, however, came at the level of atomic level structures and their associated mechanisms. this was ...201324125587
a tale of two machines: a review of the blast meeting, tucson, az, 20-24 january 2013.since its inception, bacterial locomotion and signal transduction (blast) meetings have been the place to exchange and share the latest developments in the field of bacterial signal transduction and motility. at the 12th blast meeting, held last january in tucson, az, researchers from all over the world met to report and discuss progress in diverse aspects of the field. the majority of these advances, however, came at the level of atomic level structures and their associated mechanisms. this was ...201324125587
borrelia burgdorferi oxidative stress regulator bosr directly represses lipoproteins primarily expressed in the tick during mammalian infection.differential gene expression is a key strategy adopted by the lyme disease spirochaete, borrelia burgdorferi, for adaptation and survival in the mammalian host and the tick vector. many b. burgdorferi surface lipoproteins fall into two distinct groups according to their expression patterns: one group primarily expressed in the tick and the other group primarily expressed in the mammal. here, we show that the fur homologue in this bacterium, also known as borrelia oxidative stress regulator (bosr ...201323869590
partial disruption of translational and posttranslational machinery reshapes growth rates of bartonella birtlesii.specialization of bacteria in a new niche is associated with genome repertoire changes, and speciation in bacterial specialists is associated with genome reduction. here, we tested a signature-tagged mutant library of 3,456 bartonella birtlesii clones to detect mutants that could grow rapidly in vitro. overall, we found 124 mutants that grew faster than the parental wild-type strain in vitro. we sequenced the genomes of the four mutants with the most rapid growth (formed visible colonies in only ...201323611908
molecular mechanisms and clinical impact of acquired and intrinsic fosfomycin resistance.bacterial infections caused by antibiotic-resistant isolates have become a major health problem in recent years, since they are very difficult to treat, leading to an increase in morbidity and mortality. fosfomycin is a broad-spectrum bactericidal antibiotic that inhibits cell wall biosynthesis in both gram-negative and gram-positive bacteria. this antibiotic has a unique mechanism of action and inhibits the initial step in peptidoglycan biosynthesis by blocking the enzyme, mura. fosfomycin has ...201327029300
swarming: flexible roaming plans.movement over an agar surface via swarming motility is subject to formidable challenges not encountered during swimming. bacteria display a great deal of flexibility in coping with these challenges, which include attracting water to the surface, overcoming frictional forces, and reducing surface tension. bacteria that swarm on "hard" agar surfaces (robust swarmers) display a hyperflagellated and hyperelongated morphology. bacteria requiring a "softer" agar surface (temperate swarmers) do not exh ...201323264580
cytotoxic chromosomal targeting by crispr/cas systems can reshape bacterial genomes and expel or remodel pathogenicity islands.in prokaryotes, clustered regularly interspaced short palindromic repeats (crisprs) and their associated (cas) proteins constitute a defence system against bacteriophages and plasmids. crispr/cas systems acquire short spacer sequences from foreign genetic elements and incorporate these into their crispr arrays, generating a memory of past invaders. defence is provided by short non-coding rnas that guide cas proteins to cleave complementary nucleic acids. while most spacers are acquired from phag ...201323637624
a method for molecular analysis of catalase gene diversity in seawater.catalase plays an important role in the metabolism of marine bacteria and has potential impact on the marine environment. four pcr primers were designed to amplify the catalase gene fragments in marine bacteria by applying metagenomic dna from yellow sea surface water as the template. of the four reproducible target pcr products, the longest one with 900 bp were chosen for catalase gene library construction by the t-vector and the white escherichia coli colonies in the library was screened throu ...201324426153
evolutionary history of the plant pathogenic bacterium xanthomonas axonopodis.deciphering mechanisms shaping bacterial diversity should help to build tools to predict the emergence of infectious diseases. xanthomonads are plant pathogenic bacteria found worldwide. xanthomonas axonopodis is a genetically heterogeneous species clustering, into six groups, strains that are collectively pathogenic on a large number of plants. however, each strain displays a narrow host range. we address the question of the nature of the evolutionary processes--geographical and ecological spec ...201323505513
distinct phyllosphere bacterial communities on arabidopsis wax mutant leaves.the phyllosphere of plants is inhabited by diverse microorganisms, however, the factors shaping their community composition are not fully elucidated. the plant cuticle represents the initial contact surface between microorganisms and the plant. we thus aimed to investigate whether mutations in the cuticular wax biosynthesis would affect the diversity of the phyllosphere microbiota. a set of four arabidopsis thaliana eceriferum mutants (cer1, cer6, cer9, cer16) and their respective wild type (lan ...201324223831
effects of indole-3-acetic acid on the transcriptional activities and stress tolerance of bradyrhizobium japonicum.a genome-wide transcriptional profile of bradyrhizobium japonicum, the nitrogen-fixing endosymbiont of the soybean plant, revealed differential expression of approximately 15% of the genome after a 1 mm treatment with the phytohormone indole-3-acetic acid (iaa). a total of 1,323 genes were differentially expressed (619 up-regulated and 704 down-regulated) at a two-fold cut off with q value ≤ 0.05. general stress response genes were induced, such as those involved in response to heat, cold, oxida ...201324098533
the role of bacterial biofilms and surface components in plant-bacterial associations.the role of bacterial surface components in combination with bacterial functional signals in the process of biofilm formation has been increasingly studied in recent years. plants support a diverse array of bacteria on or in their roots, transport vessels, stems, and leaves. these plant-associated bacteria have important effects on plant health and productivity. biofilm formation on plants is associated with symbiotic and pathogenic responses, but how plants regulate such associations is unclear ...201323903045
the genome of the endophytic bacterium h. frisingense gsf30(t) identifies diverse strategies in the herbaspirillum genus to interact with plants.the diazotrophic, bacterial endophyte herbaspirillum frisingense gsf30(t) has been identified in biomass grasses grown in temperate climate, including the highly nitrogen-efficient grass miscanthus. its genome was annotated and compared with related herbaspirillum species from diverse habitats, including h. seropedicae, and further well-characterized endophytes. the analysis revealed that herbaspirillum frisingense lacks a type iii secretion system that is present in some related herbaspirillum ...201323825472
the plant microbiome.plant genomes contribute to the structure and function of the plant microbiome, a key determinant of plant health and productivity. high-throughput technologies are revealing interactions between these complex communities and their hosts in unprecedented detail.201323805896
posttranslational modification of flagellin flab in shewanella oneidensis.shewanella oneidensis is a highly motile organism by virtue of a polar, glycosylated flagellum composed of flagellins flaa and flab. in this study, the functional flagellin flab was isolated and analyzed with nano-liquid chromatography-mass spectrometry (ms) and tandem ms. in combination with the mutational analysis, we propose that the flab flagellin protein from s. oneidensis is modified at five serine residues with a series of novel o-linked posttranslational modifications (ptms) that differ ...201323543712
bacillus subtilis biofilm induction by plant polysaccharides.bacillus subtilis is a plant-beneficial gram-positive bacterium widely used as a biofertilizer. however, relatively little is known regarding the molecular processes underlying this bacterium's ability to colonize roots. in contrast, much is known about how this bacterium forms matrix-enclosed multicellular communities (biofilms) in vitro. here, we show that, when b. subtilis colonizes arabidopsis thaliana roots it forms biofilms that depend on the same matrix genes required in vitro. b. subtili ...201323569226
promise for plant pest control: root-associated pseudomonads with insecticidal activities.insects are an important and probably the most challenging pest to control in agriculture, in particular when they feed on belowground parts of plants. the application of synthetic pesticides is problematic owing to side effects on the environment, concerns for public health and the rapid development of resistance. entomopathogenic bacteria, notably bacillus thuringiensis and photorhabdus/xenorhabdus species, are promising alternatives to chemical insecticides, for they are able to efficiently k ...201323914197
methods for analysis of disease resistance and the defense response in arabidopsis.many g proteins are involved in the plant defense responses against pathogen infection. with arabidopsis as a model, this chapter describes the protocols commonly used for inoculating plants with pseudomonas syringae (a bacterial pathogen) and botrytis cinerea (a fungal pathogen) for analyzing disease resistance phenotypes caused by these pathogens. in addition, the procedures are provided for observation of the hypersensitive response triggered by avirulent strains of p. syringae and for analyz ...201323913035
development of a real-time microchip pcr system for portable plant disease diagnosis.rapid and accurate detection of plant pathogens in the field is crucial to prevent the proliferation of infected crops. polymerase chain reaction (pcr) process is the most reliable and accepted method for plant pathogen diagnosis, however current conventional pcr machines are not portable and require additional post-processing steps to detect the amplified dna (amplicon) of pathogens. real-time pcr can directly quantify the amplicon during the dna amplification without the need for post processi ...201324349341
repertoire, unified nomenclature and evolution of the type iii effector gene set in the ralstonia solanacearum species complex.ralstonia solanacearum is a soil-borne beta-proteobacterium that causes bacterial wilt disease in many food crops and is a major problem for agriculture in intertropical regions. r. solanacearum is a heterogeneous species, both phenotypically and genetically, and is considered as a species complex. pathogenicity of r. solanacearum relies on the type iii secretion system that injects type iii effector (t3e) proteins into plant cells. t3e collectively perturb host cell processes and modulate plant ...201324314259
ralstonia solanacearum requires pops, an ancient avre-family effector, for virulence and to overcome salicylic acid-mediated defenses during tomato pathogenesis.during bacterial wilt of tomato, the plant pathogen ralstonia solanacearum upregulates expression of pops, which encodes a type iii-secreted effector in the avre family. pops is a core effector present in all sequenced strains in the r. solanacearum species complex. the phylogeny of pops mirrors that of the species complex as a whole, suggesting that this is an ancient, vertically inherited effector needed for association with plants. a pops mutant of r. solanacearum uw551 had reduced virulence ...201324281716
draft genome sequence of xanthomonas fragariae reveals reductive evolution and distinct virulence-related gene content.xanthomonas fragariae (xf) is a bacterial strawberry pathogen and an a2 quarantine organism on strawberry planting stock in the eu. it is taxonomically and metabolically distinct within the genus xanthomonas, and known for its host specificity. as part of a broader pathogenicity study, the genome of a belgian, virulent xf strain (lmg 25863) was assembled to draft status and examined for its pathogenicity related gene content.201324274055
type iii chaperones & co in bacterial plant pathogens: a set of specialized bodyguards mediating effector delivery.gram-negative plant pathogenic bacteria possess a type iii secretion system (t3ss) to inject bacterial proteins, called type iii effectors (t3es), into host cells through a specialized syringe structure. t3es are virulence factors that can suppress plant immunity but they can also conversely be recognized by the plant and trigger specific resistance mechanisms. the t3ss and injected t3es play a central role in determining the outcome of a host-pathogen interaction. still little is known in plant ...201324319448
novel plant inputs influencing ralstonia solanacearum during infection.ralstonia solanacearum is a soil and water-borne pathogen that can infect a wide range of plants and cause the devastating bacterial wilt disease. to successfully colonize a host, r. solanacearum requires the type iii secretion system (t3ss), which delivers bacterial effector proteins inside the plant cells. hrpg is a central transcriptional regulator that drives the expression of the t3ss and other virulence determinants. hrpg transcription is highly induced upon plant cell contact and its prod ...201324312090
crystallization and preliminary x-ray diffraction analyses of the tir domains of three tir-nb-lrr proteins that are involved in disease resistance in arabidopsis thaliana.the toll/interleukin-1 receptor (tir) domain is a protein-protein interaction domain that is found in both animal and plant immune receptors. the n-terminal tir domain from the nucleotide-binding (nb)-leucine-rich repeat (lrr) class of plant disease-resistance (r) proteins has been shown to play an important role in defence signalling. recently, the crystal structure of the tir domain from flax r protein l6 was determined and this structure, combined with functional studies, demonstrated that ti ...201324192368
recent advances in plant nlr structure, function, localization, and signaling.nucleotide-binding domain leucine-rich repeat (nlr) proteins play a central role in the innate immune systems of plants and vertebrates. in plants, nlr proteins function as intracellular receptors that detect pathogen effector proteins directly, or indirectly by recognizing effector-induced modifications to other host proteins. nlr activation triggers a suite of defense responses associated with programed cell death (pcd). the molecular mechanisms underlying nlr activation, and how activation is ...201324155748
auxin and the integration of environmental signals into plant root development.auxin is a versatile plant hormone with important roles in many essential physiological processes. in recent years, significant progress has been made towards understanding the roles of this hormone in plant growth and development. recent evidence also points to a less well-known but equally important role for auxin as a mediator of environmental adaptation in plants.201324136877
plant antimicrobial peptides.plant antimicrobial peptides (amps) are a component of barrier defense system of plants. they have been isolated from roots, seeds, flowers, stems, and leaves of a wide variety of species and have activities towards phytopathogens, as well as against bacteria pathogenic to humans. thus, plant amps are considered as promising antibiotic compounds with important biotechnological applications. plant amps are grouped into several families and share general features such as positive charge, the prese ...201324092498
plant antimicrobial peptides.plant antimicrobial peptides (amps) are a component of barrier defense system of plants. they have been isolated from roots, seeds, flowers, stems, and leaves of a wide variety of species and have activities towards phytopathogens, as well as against bacteria pathogenic to humans. thus, plant amps are considered as promising antibiotic compounds with important biotechnological applications. plant amps are grouped into several families and share general features such as positive charge, the prese ...201324092498
application of variable-number tandem-repeat typing to discriminate ralstonia solanacearum strains associated with english watercourses and disease outbreaks.variable-number tandem-repeat (vntr) analysis was used for high-resolution discrimination among ralstonia solanacearum phylotype iib sequevar 1 (piib-1) isolates and further evaluated for use in source tracing. five tandem-repeat-containing loci (comprising six tandem repeats) discriminated 17 different vntr profiles among 75 isolates from potato, geranium, bittersweet (solanum dulcamara), tomato, and the environment. r. solanacearum isolates from crops at three unrelated outbreak sites where ri ...201323892739
elicitor-induced defense responses in solanum lycopersicum against ralstonia solanacearum.we investigated on important parameters of induced resistance in hydroponic tomato (solanum lycopersicum) against ralstonia solanacearum using the elicitors chitosan (cht), salicylic acid (sa), and jasmonic acid (ja). the increase in total phenolic content of roots by the elicitors was significantly higher than control. most pronounced increase in lignin synthesis was triggered by sa followed by cht. at 24 h post-elicitation (hpe), the activity of phenylalanine ammonia lyase was 4.5 times higher ...201324187521
evolution and conservation of plant nlr functions.in plants and animals, nucleotide-binding domain and leucine-rich repeats (nlr)-containing proteins play pivotal roles in innate immunity. despite their similar biological functions and protein architecture, comparative genome-wide analyses of nlrs and genes encoding nlr-like proteins suggest that plant and animal nlrs have independently arisen in evolution. furthermore, the demonstration of interfamily transfer of plant nlr functions from their original species to phylogenetically distant speci ...201324093022
intrinsic disorder in pathogen effectors: protein flexibility as an evolutionary hallmark in a molecular arms race.effector proteins represent a refined mechanism of bacterial pathogens to overcome plants' innate immune systems. these modular proteins often manipulate host physiology by directly interfering with immune signaling of plant cells. even if host cells have developed efficient strategies to perceive the presence of pathogenic microbes and to recognize intracellular effector activity, it remains an open question why only few effectors are recognized directly by plant resistance proteins. based on i ...201324038649
new clues in the nucleus: transcriptional reprogramming in effector-triggered immunity.the robustness of plant effector-triggered immunity is correlated with massive alterations of the host transcriptome. yet the molecular mechanisms that cause and underlie this reprogramming remain obscure. here we will review recent advances in deciphering nuclear functions of plant immune receptors and of associated proteins. important open questions remain, such as the identities of the primary transcription factors involved in control of effector-triggered immune responses, and indeed whether ...201324062762
quorum quenching enzymes and their application in degrading signal molecules to block quorum sensing-dependent infection.with the emergence of antibiotic-resistant strains of bacteria, the available options for treating bacterial infections have become very limited, and the search for a novel general antibacterial therapy has received much greater attention. quorum quenching can be used to control disease in a quorum sensing system by triggering the pathogenic phenotype. the interference with the quorum sensing system by the quorum quenching enzyme is a potential strategy for replacing traditional antibiotics beca ...201324065091
pivoting the plant immune system from dissection to deployment.diverse and rapidly evolving pathogens cause plant diseases and epidemics that threaten crop yield and food security around the world. research over the last 25 years has led to an increasingly clear conceptual understanding of the molecular components of the plant immune system. combined with ever-cheaper dna-sequencing technology and the rich diversity of germ plasm manipulated for over a century by plant breeders, we now have the means to begin development of durable (long-lasting) disease re ...201323950531
xopac-triggered immunity against xanthomonas depends on arabidopsis receptor-like cytoplasmic kinase genes pbl2 and ripk.xanthomonas campestris pv. campestris (xcc) colonizes the vascular system of brassicaceae and ultimately causes black rot. in susceptible arabidopsis plants, xopac type iii effector inhibits by uridylylation positive regulators of the pamp-triggered immunity such as the receptor-like cytoplasmic kinases (rlck) bik1 and pbl1. in the resistant ecotype col-0, xopac is a major avirulence gene of xcc. in this study, we show that both the rlck interaction domain and the uridylyl transferase domain of ...201323951354
hrp mutant bacteria as biocontrol agents: toward a sustainable approach in the fight against plant pathogenic bacteria.sustainable agriculture necessitates development of environmentally safe methods to protect plants against pathogens. among these methods, application of biocontrol agents has been efficiently used to minimize disease development. here we review current understanding of mechanisms involved in biocontrol of the main gram-phytopathogenic bacteria-induced diseases by plant inoculation with strains mutated in hrp (hypersensitive response and pathogenicity) genes. these mutants are able to penetrate ...201323887499
cryptogein-induced transcriptional reprogramming in tobacco is light dependent.the fungal elicitor cryptogein triggers a light-dependent hypersensitive response in tobacco (nicotiana tabacum). to assess the effect of light on this nonhost resistance in more detail, we studied various aspects of the response under dark and light conditions using the tobacco-cryptogein experimental system. here, we show that light drastically alters the plant's transcriptional response to cryptogein, notably by dampening the induction of genes involved in multiple processes, such as ethylene ...201323878079
the xanthomonas campestris type iii effector xopj targets the host cell proteasome to suppress salicylic-acid mediated plant defence.the phytopathogenic bacterium xanthomonas campestris pv. vesicatoria (xcv) requires type iii effector proteins (t3es) for virulence. after translocation into the host cell, t3es are thought to interact with components of host immunity to suppress defence responses. xopj is a t3e protein from xcv that interferes with plant immune responses; however, its host cellular target is unknown. here we show that xopj interacts with the proteasomal subunit rpt6 in yeast and in planta to inhibit proteasome ...201323785289
pathogenicity of and plant immunity to soft rot pectobacteria.soft rot pectobacteria are broad host range enterobacterial pathogens that cause disease on a variety of plant species including the major crop potato. pectobacteria are aggressive necrotrophs that harbor a large arsenal of plant cell wall-degrading enzymes as their primary virulence determinants. these enzymes together with additional virulence factors are employed to macerate the host tissue and promote host cell death to provide nutrients for the pathogens. in contrast to (hemi)biotrophs such ...201323781227
the role of tir-nbs and tir-x proteins in plant basal defense responses.toll/interleukin receptor (tir) domain-containing proteins encoded in the arabidopsis (arabidopsis thaliana) genome include the tir-nucleotide binding site (tn) and tir-unknown site/domain (tx) families. we investigated the function of these proteins. transient overexpression of five tx and tn genes in tobacco (nicotiana benthamiana) induced chlorosis. this induced chlorosis was dependent on enhanced disease resistance1, a dependency conserved in both tobacco and arabidopsis. stable overexpressi ...201323735504
natural genetic variation of xanthomonas campestris pv. campestris pathogenicity on arabidopsis revealed by association and reverse genetics.abstract the pathogenic bacterium xanthomonas campestris pv. campestris, the causal agent of black rot of brassicaceae, manipulates the physiology and the innate immunity of its hosts. association genetic and reverse-genetic analyses of a world panel of 45 x. campestris pv. campestris strains were used to gain understanding of the genetic basis of the bacterium's pathogenicity to arabidopsis thaliana. we found that the compositions of the minimal predicted type iii secretome varied extensively, ...201323736288
glutathione and tryptophan metabolism are required for arabidopsis immunity during the hypersensitive response to hemibiotrophs.the hypersensitive response (hr) is a type of strong immune response found in plants that is accompanied by localized cell death. however, it is unclear how hr can block a broad range of pathogens with different infective modes. in this study, we report that γ-glutamylcysteine synthetase gsh1, which is critical for glutathione biosynthesis, and tryptophan (trp) metabolism contribute to hr and block development of fungal pathogens with hemibiotrophic infective modes. we found that gsh1 is involve ...201323696664
the role of noi-domain containing proteins in plant immune signaling.here we present an overview of our existing knowledge on the function of rin4 as a regulator of plant defense and as a guardee of multiple plant r-proteins. domain analysis of rin4 reveals two noi domains. the noi domain was originally identified in a screen for nitrate induced genes. the domain is comprised of approximately 30 amino acids and contains 2 conserved motifs (pxfgxw and y/ftxxf). the noi gene family contains members exclusively from the plant lineage as far back as moss. in addition ...201323672422
isr meets sar outside: additive action of the endophyte bacillus pumilus inr7 and the chemical inducer, benzothiadiazole, on induced resistance against bacterial spot in field-grown pepper.induced resistance has been recognized as an attractive tool for plant disease management in modern agriculture. during the last two decades, studies on chemically- and biologically elicited induced resistance have revealed previously unknown features of the plant defense response including defense priming. as a biological trigger for induced resistance, plant growth-promoting rhizobacteria (pgpr) are a group of root-associated bacteria that can reduce plant disease severity and incidence, and a ...201323717313
genome-wide identification and functional analyses of calmodulin genes in solanaceous species.calmodulin (cam) is a major calcium sensor in all eukaryotes. it binds calcium and modulates the activity of a wide range of downstream proteins in response to calcium signals. however, little is known about the cam gene family in solanaceous species, including the economically important species, tomato (solanum lycopersicum), and the gene silencing model plant, nicotiana benthamiana. moreover, the potential function of cam in plant disease resistance remains largely unclear.201323621884
current knowledge on the ralstonia solanacearum type iii secretion system. 201323617636
the xylem as battleground for plant hosts and vascular wilt pathogens.vascular wilts are among the most destructive plant diseases that occur in annual crops as well as in woody perennials. these diseases are generally caused by soil-borne bacteria, fungi, and oomycetes that infect through the roots and enter the water-conducting xylem vessels where they proliferate and obstruct the transportation of water and minerals. as a consequence, leaves wilt and die, which may lead to impairment of the whole plant and eventually to death of the plant. cultural, chemical, a ...201323630534
regulate and be regulated: integration of defense and other signals by the atmyb30 transcription factor.transcriptional regulation in host cells plays a crucial role in the establishment of plant defense and associated cell death in response to pathogen attack. here, we review our current knowledge of the transcriptional control of plant defenses with a focus on the myb family of transcription factors (tfs). within this family, the arabidopsis myb protein atmyb30 is a key regulator of plant defenses and one of the best characterized myb regulators directing defense-related transcriptional response ...201323596456
nuclear jasmonate and salicylate signaling and crosstalk in defense against pathogens.an extraordinary progress has been made over the last two decades on understanding the components and mechanisms governing plant innate immunity. after detection of a pathogen, effective plant resistance depends on the activation of a complex signaling network integrated by small signaling molecules and hormonal pathways, and the balance of these hormone systems determines resistance to particular pathogens. the discovery of new components of hormonal signaling pathways, including plant nuclear ...201323577014
plant nucleotide binding site-leucine-rich repeat (nbs-lrr) genes: active guardians in host defense responses.the most represented group of resistance genes are those of the nucleotide binding site-leucine-rich repeat (nbs-lrr) class. these genes are very numerous in the plant genome, and they often occur in clusters at specific loci following gene duplication and amplification events. to date, hundreds of resistance genes and relatively few quantitative trait loci for plant resistance to pathogens have been mapped in different species, with some also cloned. when these nbs-lrr genes have been physically ...201323549266
recent evolutionary radiation and host plant specialization in the xylella fastidiosa subspecies native to the united states.the bacterial pathogen, xylella fastidiosa, infects many plant species in the americas, making it a good model for investigating the genetics of host adaptation. we used multilocus sequence typing (mlst) to identify isolates of the native u.s. subsp. multiplex that were largely unaffected by intersubspecific homologous recombination (ihr) and to investigate how their evolutionary history influences plant host specialization. we identified 110 "non-ihr" isolates, 2 minimally recombinant "intermed ...201323354698
Refresh
firstprev
...51525354555657585960...
nextlast
Displaying items 5901 - 6000 of 9107