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microbial degradation of lobster shells to extract chitin derivatives for plant disease management.biodegradation of lobster shells by chitinolytic microorganisms are an environment safe approach to utilize lobster processing wastes for chitin derivation. in this study, we report degradation activities of two microbes, "s223" and "s224" isolated from soil samples that had the highest rate of deproteinization, demineralization and chitinolysis among ten microorganisms screened. isolates s223 and s224 had 27.3 and 103.8 protease units mg(-1) protein and 12.3 and 11.2 μg ml(-1) of calcium in the ...201728529501
structure of c-terminal domain of peptidyl-prolyl cis-trans isomerase from pseudomonas syringae pv. tomato str. dc3000 at 1.6å resolution.peptidyl-prolyl cis-trans isomerase (ppiase) catalyses the conversion between the cis and trans configurations of proline which switches the backbone conformation of peptides. we determined the crystal structure of the c-terminal domain of ppiase from pseudomonas syringae pv. tomato dc3000 (pspto dc3000) at 1.6å resolution. structural comparison of pspto-ppiase with its homologues suggested that the successive arrangement of residues with small side-chain in loop 4 contributes to its substrate s ...201728413971
inhibitory effect of thymus vulgaris and origanum vulgare essential oils on virulence factors of phytopatogenic pseudomonas syringae strains.pseudomonas syringae is a phytopathogenic bacterium that causes lesions in the leaves during the colonization process. the damage is associated to the production of many virulence factors such as biofilm and phytotoxins. the essential oils of thymus vulgaris and origanum vulgare have demonstrated the ability to inhibit p. syringae. the aim of this study was to investigate the effects of t. vulgaris and o. vulgare essential oils on the production of virulence factors of phytopatogenic p. syringae ...201728403565
regulation of mir163 and its targets in defense against pseudomonas syringae in arabidopsis thaliana.small rnas are important regulators for a variety of biological processes, including leaf development, flowering-time, embryogenesis and defense responses. mir163 is a non-conserved mirna and its locus has evolved recently through inverted duplication of its target genes to which they belong to the sabath family of related small-molecule methyltransferases (mts). in arabidopsis thaliana, previous study demonstrated that mir163 accumulation was induced by alamethicin treatment, suggesting its rol ...201728401908
expression of hopai interferes with map kinase signalling in magnaporthe oryzae.the pmk1 and mps1 map kinases are essential for appressorium formation and plant infection in magnaporthe oryzae. however, their exact roles during invasive growth are not clear because pmk1 and mps1 mutants are defective in penetration. to further characterize their functions after penetration, in this study we expressed the pseudomonas syringae effector hopai known to inactivate plant map kinases in m. oryzae. constitutive expression of hopai with the rp27 or trpc promoter resulted in defects ...201728799700
seasonal variation in phytochemicals and nutraceutical potential of begonia nelumbiifolia consumed in puebla, méxico.begonia nelumbiifolia is a traditional edible plant consumed and commercialized in the northern highlands of puebla, méxico. the present study reports the seasonal variation in proximate analysis as well as organic acids, carotenoids and flavonoids content in both leaves and stalks of this plant. the stalks contained low concentrations of protein (~3%), fiber (~1.5%) and nitrogen free extract (~0.26%) during the time of study. both organs showed contents of oxalic acid (91-103 mg 100 g(-1) fw), ...201728559607
investigation on the interaction of pseudomonas syringae effector avrpto with atrabe1d gtpase.the tomato bacterial speck is a worldwide disease. it is caused by the infection of pathogenic pseudomonas syringae pv. tomato which delivers the effector avrpto into the host cells via the type iii secretion system. avrpto interacts rab8 subfamily protein in the gtp-bound form and participates in the response to pathogen infection, but the pathogenic mechanism involved by rab8 subfamily remains elusive. here, we investigated on the interrelationship of avrpto8-159 with arabidopsis thaliana gtp- ...201728641564
suppression of plant immune responses by the pseudomonas savastanoi pv. savastanoi ncppb 3335 type iii effector tyrosine phosphatases hopao1 and hopao2.the effector repertoire of the olive pathogen p. savastanoi pv. savastanoi ncppb 3335 includes two members of the hopao effector family, one of the most diverse t3e families of the p. syringae complex. the study described here explores the phylogeny of these dissimilar members, hopao1 and hopao2, among the complex and reveals their activities as immune defense suppressors. although hopao1 is predominantly encoded by phylogroup 3 strains isolated from woody organs of woody hosts, both hopao1 and ...201728529516
age-related resistance in arabidopsis thaliana involves the mads-domain transcription factor short vegetative phase and direct action of salicylic acid on pseudomonas syringae.arabidopsis thaliana exhibits a developmentally regulated disease-resistance response known as age-related resistance (arr), a process that requires intercellular accumulation of salicylic acid (sa), which is thought to act as an antimicrobial agent. arr is characterized by enhanced resistance to some pathogens at the late adult-vegetative and reproductive stages. while the transition to flowering does not cause the onset of arr, both processes involve the mads-domain transcription factor short ...201728812948
alteration of cell wall xylan acetylation trigger defense responses that counterbalance the immune deficiencies of plants impaired in the β subunit of the heterotrimeric g protein.arabidopsis heterotrimeric g protein complex modulates pathogen associated molecular pattern-triggered immunity (pti) and disease resistance responses to different type of pathogens. it also plays a role in plant cell wall integrity as mutants impaired in the gβ (agb1-2) or gγ subunits have an altered wall composition compared to wild-type plants. here we performed a mutant screen to identify suppressors of agb1-2 (sgb) that restore susceptibility to pathogens to wild-type levels. out of the fou ...201728792629
different arabidopsis thaliana photosynthetic and defense responses to hemibiotrophic pathogen induced by local or distal inoculation of burkholderia phytofirmans.pathogen infection of plant results in modification of photosynthesis and defense mechanisms. beneficial microorganisms are known to improve plant tolerance to stresses. burkholderia phytofirmans psjn (bp), a beneficial endophytic bacterium, promotes growth of a wide range of plants and induces plant resistance against abiotic and biotic stresses such as coldness and infection by a necrotrophic pathogen. however, mechanisms underlying its role in plant tolerance towards (hemi)biotrophic invaders ...201728840464
studies on the o-specific polysaccharide of the lipopolysaccharide from the pseudomonas mediterranea strain c5p1rad1, a bacterium pathogenic of tomato and chrysanthemum.an o-specific polysaccharide (ops) was isolated from the lipopolysaccharide of pseudomonas mediterranea strain c5p1rad1, the causal agents of tomato pith necrosis and chrysanthemum stem rot, and studied by one- and two-dimensional (1)h and (13)c nmr spectroscopy. the following structure of the trisaccharide repeating unit of the ops was established, which, to our knowledge, is unique among the known bacterial polysaccharide structures: →4)-β-d-manpnac3naca-(1 → 4)-β-d-manpnac3naca-(1 → 3)-α-d-qu ...201728601025
knots untie: molecular determinants involved in knot formation induced by pseudomonas savastanoi in woody hosts.the study of the molecular basis of tree diseases is lately receiving a renewed attention, especially with the emerging perception that pathogens require specific pathogenicity and virulence factors to successfully colonize woody hosts. pathosystems involving woody plants are notoriously difficult to study, although the use of model bacterial strains together with genetically homogeneous micropropagated plant material is providing a significant impetus to our understanding of the molecular deter ...201728680437
silencing of atrap, a target gene of a bacteria-induced small rna, triggers antibacterial defense responses through activation of lsu2 and down-regulation of glk1.plants fine-tune their sophisticated immunity systems in response to pathogen infections. we previously showed that atlsirna-1, a bacteria-induced plant endogenous small interfering rna, silences the atrap gene, which encodes a putative rna binding protein. in this study, we demonstrate that atrap functions as a negative regulator in plant immunity by characterizing molecular and biological responses of the knockout mutant and overexpression lines of atrap upon bacterial infection. atrap is loca ...201728656601
network analysis reveals a common host-pathogen interaction pattern in arabidopsis immune responses.many plant pathogens secrete virulence effectors into host cells to target important proteins in host cellular network. however, the dynamic interactions between effectors and host cellular network have not been fully understood. here, an integrative network analysis was conducted by combining arabidopsis thaliana protein-protein interaction network, known targets of pseudomonas syringae and hyaloperonospora arabidopsidis effectors, and gene expression profiles in the immune response. in particu ...201728611808
resistance to powdery mildew8.1 boosts pattern-triggered immunity against multiple pathogens in arabidopsis and rice.the arabidopsis gene resistance to powdery mildew8.1 (rpw8.1) confers resistance to virulent fungal and oomycete pathogens that cause powdery mildew and downy mildew, respectively. however, the underlying mechanism remains unclear. here, we show that ectopic expression of rpw8.1 boosts pattern-triggered immunity (pti) resulting in enhanced resistance against different pathogens in both arabidopsis and rice. in arabidopsis, transcriptome analysis revealed that ectopic expression of rpw8.1-yfp con ...201728640974
the powdery mildew-resistant arabidopsis mlo2 mlo6 mlo12 triple mutant displays altered infection phenotypes with diverse types of phytopathogens.arabidopsis thaliana mlo2 mlo6 mlo12 triple mutant plants exhibit complete immunity against infection by otherwise virulent obligate biotrophic powdery mildew fungi such as golovinomyces orontii. while this phenotype is well documented, the interaction profile of the triple mutant with other microbes is underexplored and incomplete. here, we thoroughly assessed and quantified the infection phenotypes of two independent powdery mildew-resistant triple mutant lines with a range of microbes. these ...201728839137
rational design of cyclic antimicrobial peptides based on bpc194 and bpc198.a strategy for the design of antimicrobial cyclic peptides derived from the lead compounds c(kklkkfkklq) (bpc194) and c(klkkkfkklq) (bpc198) is reported. first, the secondary β-structure of bpc194 and bpc198 was analyzed by carrying out molecular dynamics (md) simulations. then, based on the sequence pattern and the β-structure of bpc194 or bpc198, fifteen analogues were designed and synthesized on solid-phase. the best peptides (bpc490, bpc918, and bpc924) showed minimum inhibitory concentratio ...201728672817
sde5, a putative rna export protein, participates in plant innate immunity through a flagellin-dependent signaling pathway in arabidopsis.in eukaryotes, rna silencing, mediated by small interfering rnas, is an evolutionarily widespread and versatile silencing mechanism that plays an important role in various biological processes. increasing evidences suggest that various components of rna silencing pathway are involved in plant defense machinery against microbial pathogens in arabidopsis thaliana. here, we show genetic and molecular evidence that arabidopsis sde5 is required to generate an effective resistance against the biotroph ...201728851870
the sal-pap chloroplast retrograde pathway contributes to plant immunity by regulating glucosinolate pathway and phytohormone signaling.chloroplasts have a crucial role in plant immunity against pathogens. increasing evidence suggests that phytopathogens target chloroplast homeostasis as a pathogenicity mechanism. in order to regulate the performance of chloroplasts under stress conditions, chloroplasts produce retrograde signals to alter nuclear gene expression. many signals for the chloroplast retrograde pathway have been identified, including chlorophyll intermediates, reactive oxygen species, and metabolic retrograde signals ...201728703028
the ferric uptake regulator fur is conditionally essential in pseudomonas aeruginosa.in pseudomonas aeruginosa the ferric uptake regulator protein (fur) controls both metabolism and virulence in response to iron availability. differently from other bacteria, attempts to obtain fur deletion mutants in p. aeruginosa failed, leading to the assumption that fur is an essential protein in this bacterium. by investigating a p. aeruginosa fur conditional mutant, we demonstrate that fur is not essential for p. aeruginosa growth in liquid media, biofilm formation, and pathogenicity in an ...201728847923
pseudomonas predators: understanding and exploiting phage-host interactions.species in the genus pseudomonas thrive in a diverse set of ecological niches and include crucial pathogens, such as the human pathogen pseudomonas aeruginosa and the plant pathogen pseudomonas syringae. the bacteriophages that infect pseudomonas spp. mirror the widespread and diverse nature of their hosts. therefore, pseudomonas spp. and their phages are an ideal system to study the molecular mechanisms that govern virus-host interactions. furthermore, phages are principal catalysts of host evo ...201728649138
in-silico taxonomic classification of 373 genomes reveals species misidentification and new genospecies within the genus pseudomonas.the genus pseudomonas has one of the largest diversity of species within the bacteria kingdom. to date, its taxonomy is still being revised and updated. due to the non-standardized procedure and ambiguous thresholds at species level, largely based on 16s rrna gene or conventional biochemical assay, species identification of publicly available pseudomonas genomes remains questionable. in this study, we performed a large-scale analysis of all pseudomonas genomes with species designation (excluding ...201728747902
multiple dictyostelid species destroy biofilms of klebsiella oxytoca and other gram negative species.dictyostelids are free-living phagocytes that feed on bacteria in diverse habitats. when bacterial prey is in short supply or depleted, they undergo multicellular development culminating in the formation of dormant spores. in this work, we tested isolates representing four dictyostelid species from two genera (dictyostelium and polysphondylium) for the potential to feed on biofilms preformed on glass and polycarbonate surfaces. the abilities of dictyostelids were monitored for three hallmarks of ...201728499132
a one-step procedure for immobilising the thermostable carbonic anhydrase (sspca) on the surface membrane of escherichia coli.the carbonic anhydrase superfamily (ca, ec 4.2.1.1) of metalloenzymes is present in all three domains of life (eubacteria, archaea, and eukarya), being an interesting example of convergent/divergent evolution, with its seven families (α-, β-, γ-, δ-, ζ-, η-, and θ-cas) described so far. cas catalyse the simple, but physiologically crucial reaction of carbon dioxide hydration to bicarbonate and protons. recently, our groups characterised the α-ca from the thermophilic bacterium, sulfurihydrogenib ...201728791907
a conserved ear motif is required for avirulence and stability of the ralstonia solanacearum effector popp2 in planta.ralstonia solanacearum is the causal agent of the devastating bacterial wilt disease in many high value solanaceae crops. r. solanacearum secretes around 70 effectors into host cells in order to promote infection. plants have, however, evolved specialized immune receptors that recognize corresponding effectors and confer qualitative disease resistance. in the model species arabidopsis thaliana, the paired immune receptors rrs1 (resistance to ralstonia solanacearum 1) and rps4 (resistance to pseu ...201728824668
testing differences between pathogen compositions with small samples and sparse data.the structure of pathogen populations is an important driver of epidemics affecting crops and natural plant communities. comparing the composition of two pathogen populations consisting of assemblages of genotypes or phenotypes is a crucial, recurrent question encountered in many studies in plant disease epidemiology. determining whether there is a significant difference between two sets of proportions is also a generic question for numerous biological fields. when samples are small and data are ...201728677479
tyrosine-610 in the receptor kinase bak1 does not play a major role in brassinosteroid signaling or innate immunity.the plasma membrane-localized bri1-associated kinase1 (bak1) functions as a co-receptor with several receptor kinases including the brassinosteroid (br) receptor brassinosteroid-insensitive 1 (bri1), which is involved in growth, and the receptors for bacterial flagellin and ef-tu, flagellin-sensing 2 (fls2) and ef-tu receptor (efr), respectively, which are involved in immunity. bak1 is a dual specificity protein kinase that can autophosphorylate on serine, threonine and tyrosine residues. it was ...201728824659
stomate-based defense and environmental cues.environmental conditions play crucial roles in modulating immunity and disease in plants. for instance, many bacterial disease outbreaks occur after periods of high humidity and rain. a critical step in bacterial infection is entry into the plant interior through wounds or natural openings, such as stomata. bacterium-triggered stomatal closure is an integral part of the plant immune response to reduce pathogen invasion. recently, we found that high humidity compromises stomatal defense, which is ...201728816601
holaphyllamine, a steroid, is able to induce defense responses in arabidopsis thaliana and increases resistance against bacterial infection.a chemical screen of plant-derived compounds identified holaphyllamine, a steroid, able to trigger defense responses in arabidopsis thaliana and improve resistance against the pathogenic bacterium pseudomonas syringae pv tomato dc3000. a chemical screen of 1600 plant-derived compounds was conducted and allowed the identification of a steroid able to activate defense responses in a. thaliana at a concentration of 1 µm without altering growth. the identified compound is holaphyllamine (hpa) whose ...201728815300
occurrence and epidemics of bacterial canker of kiwifruit in korea.bacterial canker is the largest limiting factor in the cultivation and production of kiwifruit worldwide. typical symptoms comprise necrotic spots on leaves, canker and dieback on canes and trunks, twig wilting, and blossom necrosis. pseudomonas syringae pv. actinidiae (psa), which is the causal agent of kiwifruit bacterial canker, is divided into four biovars based on multilocus sequence analysis of different genes, additional pcr testing of pathogenic genes (argktox cluster, cfl, and various e ...201728811752
a plant effector-triggered immunity signaling sector is inhibited by pattern-triggered immunity.since signaling machineries for two modes of plant-induced immunity, pattern-triggered immunity (pti) and effector-triggered immunity (eti), extensively overlap, pti and eti signaling likely interact. in an arabidopsis quadruple mutant, in which four major sectors of the signaling network, jasmonate, ethylene, pad4, and salicylate, are disabled, the hypersensitive response (hr) typical of eti is abolished when the pseudomonas syringae effector avrrpt2 is bacterially delivered but is intact when ...201728811287
transcriptome changes in arabidopsis thaliana infected with pseudomonas syringae during drought recovery.field-grown plants experience cycles of drought stress and recovery due to variation in soil moisture status. physiological, biochemical and transcriptome responses instigated by recovery are expected to be different from drought stress and non-stressed state. such responses can further aid or antagonize the plant's interaction with the pathogen. however, at molecular level, not much is known about plant-pathogen interaction during drought recovery. in the present study, we performed a microarra ...201728831155
plc2 regulates mamp-triggered immunity by modulating ros production in arabidopsis.the activation of phosphoinositide-specific phospholipase c (pi-plc) is one of the earliest responses triggered by the recognition of several microbe-associated molecular patterns (mamps) in plants. the arabidopsis pi-plc gene family is composed of nine members. previous studies suggested a role for plc2 in mamp-triggered immunity (mti) as it is rapidly phosphorylated in vivo upon treatment with the bacterial mamp flg22. here we analyzed the role of plc2 in plant immunity using an artificial mic ...201728827453
phytohormone and putative defense gene expression differentiates the response of 'hayward' kiwifruit to psa and pfm infections.pseudomonas syringae pv. actinidiae (psa) and pseudomonas syringae pv. actinidifoliorum (pfm) are closely related pathovars infecting kiwifruit, but psa is considered one of the most important global pathogens, whereas pfm is not. in this study of actinidia deliciosa 'hayward' responses to the two pathovars, the objective was to test whether differences in plant defense responses mounted against the two pathovars correlated with the contrasting severity of the symptoms caused by them. results sh ...201728824694
structures and mechanisms of the non-heme fe(ii)- and 2-oxoglutarate-dependent ethylene-forming enzyme: substrate binding creates a twist.the ethylene-forming enzyme (efe) from pseudomonas syringae pv. phaseolicola pk2 is a member of the mononuclear nonheme fe(ii)- and 2-oxoglutarate (2og)-dependent oxygenase superfamily. efe converts 2og into ethylene plus three co2 molecules while also catalyzing the c5 hydroxylation of l-arginine (l-arg) driven by the oxidative decarboxylation of 2og to form succinate and co2. here we report 11 x-ray crystal structures of efe that provide insight into the mechanisms of these two reactions. bind ...201728780854
constitutive activity of the arabidopsis map kinase 3 confers resistance to pseudomonas syringae and drives robust immune responses.mitogen activated protein kinases (mapks) are known to be important mediators of plant responses to biotic and abiotic stresses. in a recent report, we enlarged the understanding of the arabidopsis thaliana mpk3 functions showing that the expression of a constitutively active (ca) form of the protein led to auto-immune phenotypes. ca-mpk3 plants are dwarf and display defense responses that are characterized by the accumulation of salicylic acid and phytoalexins as well as by the upregulation of ...201728766995
an essential role for the vast domain of the arabidopsis vad1 protein in the regulation of defense and cell death in response to pathogens.several regulators of programmed cell death (pcd) have been identified in plants which encode proteins with putative lipid-binding domains. among them, vad1 (vascular associated death) contains a novel protein domain called vast (vad1 analog star-related lipid transfer) still uncharacterized. the arabidopsis mutant vad1-1 has been shown to exhibit a lesion mimic phenotype with light-conditional appearance of propagative hypersensitive response-like lesions along the vascular system, associated w ...201728683084
prr2, a pseudo-response regulator, promotes salicylic acid and camalexin accumulation during plant immunity.calcium signalling mediated by calmodulin (cam) and calmodulin-like (cml) proteins is critical to plant immunity. cam and cml regulate a wide range of target proteins and cellular responses. while many cam-binding proteins have been identified, few have been characterized for their specific role in plant immunity. here, we report new data on the biological function of a cml-interacting partner, prr2 (pseudo-response regulator 2), a plant specific transcription factor. until now, the physiologica ...201728765536
pseudomonas syringae pv. tomato dc3000 polymutants deploying coronatine and two type iii effectors produce quantifiable chlorotic spots from individual bacterial colonies in nicotiana benthamiana leaves.primary virulence factors of pseudomonas syringae pv. tomato dc3000 include the phytotoxin coronatine (cor) and a repertoire of 29 effector proteins injected into plant cells by the type iii secretion system (t3ss). dc3000 derivatives differentially producing cor, the t3ss machinery, and subsets of key effectors were constructed and assayed in leaves of nicotiana benthamiana. bacteria were inoculated by dipping of whole plants and assayed for population growth and production of chlorotic spots o ...201728677296
the accumulation of β-aminobutyric acid is controlled by the plant's immune system.endogenous levels of β-aminobutyric acid (baba) increase after the molecular recognition of pathogen presence. baba is accumulated differently during resistance or susceptibility to disease. the priming molecule β-aminobutyric acid has been recently shown to be a natural product of plants, and this has provided significance to the previous discovery of a perception mechanism in arabidopsis. baba levels were found to increase after abiotic stress or infection with virulent pathogens, but the role ...201728762076
a novel family of proline/serine-rich proteins, which are phospho-targets of stress-related mitogen-activated protein kinases, differentially regulates growth and pathogen defense in arabidopsis thaliana.the molecular actions of mitogen-activated protein kinases (mapks) are ultimately accomplished by the substrate proteins where phosphorylation affects their molecular properties and function(s), but knowledge regarding plant mapk substrates is currently still fragmentary. here, we uncovered a previously uncharacterized protein family consisting of three proline/serine-rich proteins (prps) that are substrates of stress-related mapks. we demonstrated the importance of a mapk docking domain necessa ...201728755319
draft genome sequence of pseudomonas syringae pdd-32b-74, a model strain for ice-nucleation studies in the atmosphere.we report here the whole genome sequence of pseudomonas syringae pdd-32b-74, a gammaproteobacterium isolated from cloud water. this microorganism is equipped with ice-nucleation protein and biosurfactant genes that could potentially be involved in physicochemical processes in the atmosphere and clouds.201728751406
genome-wide linkage and association mapping of halo blight resistance in common bean to race 6 of the globally important bacterial pathogen.pseudomonas syringae pv. phaseolicola (psph) race 6 is a globally prevalent and broadly virulent bacterial pathogen with devastating impact causing halo blight of common bean (phaseolus vulgaris l.). common bean lines pi 150414 and cal 143 are known sources of resistance against this pathogen. we constructed high-resolution linkage maps for three recombinant inbred populations to map resistance to psph race 6 derived from the two common bean lines. this was complemented with a genome-wide associ ...201728736566
analysis of the zar1 immune complex reveals determinants for immunity and molecular interactions.plants depend on innate immunity to prevent disease. plant pathogenic bacteria, like pseudomonas syringae and xanthomonas campestris, use the type iii secretion system as a molecular syringe to inject type iii secreted effector (t3se) proteins in plants. the primary function of most t3ses is to suppress immunity; however, the plant can evolve nucleotide-binding domain-leucine-rich repeat domain-containing proteins to recognize specific t3ses. the atzar1 nlr induces strong defense responses again ...201728652264
transgenerational defense priming for crop protection against plant pathogens: a hypothesis.throughout evolution, plants have developed diverse mechanisms of defense that "prime" their innate immune system for more robust and active induction of defense responses against different types of stress. nowadays there are numerous reports concerning the molecular bases of priming, as well as the generational priming mechanisms. information concerning transgenerational priming, however, remains deficient. some reports have indicated, nonetheless, that the priming status of a plant can be inhe ...201728523009
jmj27, an arabidopsis h3k9 histone demethylase, modulates defense against pseudomonas syringae and flowering time.histone methylation is known to dynamically regulate diverse developmental and physiological processes. histone methyl marks are written by methyltransferases and erased by demethylases, and result in modification of chromatin structure to repress or activate transcription. however, little is known about how histone methylation may regulate defense mechanisms and flowering time in plants. here we report characterization of jmjc domain-containing protein 27 (jmj27), an arabidopsis jhdm2 (jmjc dom ...201728650521
regulation of growth-defense balance by the jasmonate zim-domain (jaz)-myc transcriptional module.the plant hormone jasmonate (ja) promotes the degradation of jasmonate zim-domain (jaz) proteins to relieve repression on diverse transcription factors (tfs) that execute ja responses. however, little is known about how combinatorial complexity among jaz-tf interactions maintains control over myriad aspects of growth, development, reproduction, and immunity. we used loss-of-function mutations to define epistatic interactions within the core ja signaling pathway and to investigate the contributio ...201728649719
photochemical formation of chitosan-stabilized near-infrared-absorbing silver nanoworms: a "green" synthetic strategy and activity on gram-negative pathogenic bacteria.a facile, single-step, non-seeded photochemical protocol for producing a new type of anisotropic silver nanostructure, "nanoworms", with curved longer dimensions and smooth, rounded edges. the nanoworms exhibit surface plasmon resonance (spr) absorption in the near-infrared window (nirw) region and are stabilized using biocompatible polymer chitosan, rendering biocompatibility and amplified safety for biological utility of the composition. both nirw-absorbing nanoworms and visible-absorbing nano ...201728810197
say hello to my little friends: how microbiota can modulate tree health. 201728631327
spatiotemporal monitoring of pseudomonas syringae effectors via type iii secretion using split fluorescent protein fragments.pathogenic gram-negative bacteria cause serious diseases in animals and plants. these bacterial pathogens use the type iii secretion system (t3ss) to deliver effector proteins into host cells; these effectors then localize to different subcellular compartments to attenuate immune responses by altering biological processes of the host cells. the fluorescent protein (fp)-based approach to monitor effectors secreted from bacteria into the host cells is not possible because the folded fp prevents ef ...201728619883
a lectin receptor-like kinase mediates pattern-triggered salicylic acid signaling.plant surface-localized pathogen recognition receptors (prrs) perceive conserved microbial features, termed pathogen-associated molecular patterns (pamps), resulting in disease resistance. pamp perception leads to calcium influx, mapk activation, a burst of reactive oxygen species (ros) mediated by rbohd, accumulation of the defense hormone salicylic acid (sa), and callose deposition. lectin receptor-like kinases (lecrks) belong to a specific prr family and are important players in plant innate ...201728696275
signaling from the plasma-membrane localized plant immune receptor rpm1 requires self-association of the full-length protein.plants evolved intracellular immune receptors that belong to the nod-like receptor (nlr) family to recognize the presence of pathogen-derived effector proteins. nlrs possess an n-terminal toll-like/il-1 receptor (tir) or a non-tir domain [some of which contain coiled coils (ccs)], a central nucleotide-binding (nb-arc) domain, and a c-terminal leucine-rich repeat (lrr). activation of nlr proteins results in a rapid and high-amplitude immune response, eventually leading to host cell death at the i ...201728808003
global temporal dynamic landscape of pathogen-mediated subversion of arabidopsis innate immunity.the universal nature of networks' structural and physical properties across diverse systems offers a better prospect to elucidate the interplay between a system and its environment. in the last decade, several large-scale transcriptome and interactome studies were conducted to understand the complex and dynamic nature of interactions between arabidopsis and its bacterial pathogen, pseudomonas syringae pv. tomato dc3000. we took advantage of these publicly available datasets and performed "-omics ...201728798368
temperature-mediated biosynthesis of the phytotoxin phaseolotoxin by pseudomonas syringae pv. phaseolicola depends on the autoregulated expression of the phtabc genes.pseudomonas syringae pv. phaseolicola produces phaseolotoxin in a temperature dependent manner, being optimally synthesized between 18°c and 20°c, while no detectable amounts are present above 28°c. the pht cluster, involved in the biosynthesis of phaseolotoxin, contains 23 genes that are organized in five transcriptional units. the function of most of the genes from the pht cluster is still unknown and little information about the regulatory circuitry leading to expression of these genes has be ...201728570637
effector translocation: cya reporter assay.an accurate and complete roster of the type iii effector (t3e) proteins translocated by the p. syringae type iii secretion system (t3ss) into host cells is critical to understanding the pathogen's interactions with plants. the adenylate cyclase (cya) reporter offers a highly sensitive and robust assay for monitoring the translocation of t3es. t3es are fused to the calmodulin-dependent adenylate-cyclase domain of cyaa. the t3e targets cya for translocation through the t3ss into the host cell at w ...201728667631
atmospheric co2 alters resistance of arabidopsis to pseudomonas syringae by affecting abscisic acid accumulation and stomatal responsiveness to coronatine.atmospheric co2 influences plant growth and stomatal aperture. effects of high or low co2 levels on plant disease resistance are less well understood. here, resistance of arabidopsis thaliana against the foliar pathogen pseudomonas syringae pv. tomato dc3000 (pst) was investigated at three different co2 levels: high (800 ppm), ambient (450 ppm), and low (150 ppm). under all conditions tested, infection by pst resulted in stomatal closure within 1 h after inoculation. however, subsequent stomatal ...201728559899
pseudomonas caspiana sp. nov., a citrus pathogen in the pseudomonas syringae phylogenetic group.in a screening by multilocus sequence analysis of pseudomonas strains isolated from diverse origins, 4 phylogenetically closely related strains (fbf58, fbf102(t), fbf103, and fbf122) formed a well-defined cluster in the pseudomonas syringae phylogenetic group. the strains were isolated from citrus orchards in northern iran with disease symptoms in the leaves and stems and its pathogenicity against citrus plants was demonstrated. the whole genome of the type strain of the proposed new species (fb ...201728552245
cbl-interacting protein kinase 6 negatively regulates immune response to pseudomonas syringae in arabidopsis.cytosolic calcium ion (ca2+) is an essential mediator of the plant innate immune response. here, we report that a calcium-regulated protein kinase calcineurin b-like protein (cbl)-interacting protein kinase 6 (cipk6) functions as a negative regulator of immunity against the bacterial pathogen pseudomonas syringae in arabidopsis thaliana. arabidopsis lines with compromised expression of cipk6 exhibited enhanced disease resistance to the bacterial pathogen and to p. syringae harboring certain but ...201728541442
the tomato kinase pti1 contributes to production of reactive oxygen species in response to two flagellin-derived peptides and promotes resistance to pseudomonas syringae infection.the pti1 kinase was identified from a reverse genetic screen as contributing to pattern-triggered immunity (pti) against pseudomonas syringae pv. tomato (pst). the tomato genome has two pti1 genes, referred to as pti1a and pti1b. a hairpin-pti1 (hppti1) construct was developed and was used to generate two independent stable transgenic tomato lines that had reduced transcript abundance of both genes. in response to p. syringae pv. tomato inoculation, these hppti1 plants developed more severe dise ...201728535079
sg2-type r2r3-myb transcription factor myb15 controls defense-induced lignification and basal immunity in arabidopsis.lignification of cell wall appositions is a conserved basal defense mechanism in the plant innate immune response. however, the genetic pathway controlling defense-induced lignification remains unknown. here, we demonstrate the arabidopsis thaliana sg2-type r2r3-myb transcription factor myb15 as a regulator of defense-induced lignification and basal immunity. loss of myb15 reduces the content but not the composition of defense-induced lignin, whereas constitutive expression of myb15 increases li ...201728733420
a non-targeted metabolomics approach unravels the vocs associated with the tomato immune response against pseudomonas syringae.volatile organic compounds (vocs) emitted by plants are secondary metabolites that mediate the plant interaction with pathogens and herbivores. these compounds may perform direct defensive functions, i.e., acting as antioxidant, antibacterial, or antifungal agents, or indirectly by signaling the activation of the plant's defensive responses. using a non-targeted gc-ms metabolomics approach, we identified the profile of the vocs associated with the differential immune response of the rio grande t ...201728725238
comparative study of arabidopsis pbs1 and a wheat pbs1 homolog helps understand the mechanism of pbs1 functioning in innate immunity.arabidopsis avrpphb susceptible1 (pbs1) serves as a "decoy" in activating resistance to pseudomonas syringae5 (rps5) upon cleavage by pseudomonas phaseolicola b (avrpphb), a pseudomonas syringae effector. the semph motif in pbs1 was thought to allow it to be distinguished by rps5 from the closely related arabidopsis kinases. however, the underlying mechanism is not fully understood. here, we isolated and characterized a wheat pbs1 homolog, tapbs1. although this plasma membrane-localized kinase c ...201728710392
the ecf sigma factor, pspto_1043, in pseudomonas syringae pv. tomato dc3000 is induced by oxidative stress and regulates genes involved in oxidative stress response.the bacterial plant pathogen pseudomonas syringae adapts to changes in the environment by modifying its gene expression profile. in many cases, the response is mediated by the activation of extracytoplasmic function (ecf) sigma factors that direct rna polymerase to transcribe specific sets of genes. in this study we focus on pspto_1043, one of ten ecf sigma factors in p. syringae pv. tomato dc3000 (dc3000). pspto_1043, together with pspto_1042, encode an rpoersp/chrr-like sigma/anti-sigma factor ...201728700608
bio-fabrication of silver nanoparticles using the leaf extract of an ancient herbal medicine, dandelion (taraxacum officinale), evaluation of their antioxidant, anticancer potential, and antimicrobial activity against phytopathogens.in recent years, the use of nanoparticle-based antimicrobials has been increased due to many advantages over conventional agrochemicals. this study investigates the utilization of common medicinal plant dandelion, taraxacum officinale, for the synthesis of silver nanoparticles (tol-agnps). agnps were evaluated for antimicrobial activity against two important phytopathogens, xanthomonas axonopodis and pseudomonas syringae. the morphology, size, and structure of tol-agnps were characterized using ...201728699009
pathogen exploitation of an abscisic acid- and jasmonate-inducible mapk phosphatase and its interception by arabidopsis immunity.phytopathogens promote virulence by, for example, exploiting signaling pathways mediated by phytohormones such as abscisic acid (aba) and jasmonate (ja). some plants can counteract pathogen virulence by invoking a potent form of immunity called effector-triggered immunity (eti). here, we report that aba and ja mediate inactivation of the immune-associated map kinases (mapks), mpk3 and mpk6, in arabidopsis thaliana aba induced expression of genes encoding the protein phosphatases 2c (pp2cs), hai1 ...201728652328
interplay of pathogen-induced defense responses and symbiotic establishment in medicago truncatula.suppression of host innate immunity appears to be required for the establishment of symbiosis between rhizobia and host plants. in this study, we established a system that included a host plant, a bacterial pathogen and a symbiotic rhizobium to study the role of innate immunity during symbiotic interactions. a pathogenic bacterium, pseudomonas syringae pv. tomato strain dc3000 (pst dc3000), was shown to cause chlorosis in medicago truncatula a17. sinorhizobium meliloti strain sm2011 (sm2011) and ...201728611764
direct and indirect visualization of bacterial effector delivery into diverse plant cell types during infection.to cause disease, diverse pathogens deliver effector proteins into host cells. pathogen effectors can inhibit defense responses, alter host physiology, and represent important cellular probes to investigate plant biology. however, effector function and localization have primarily been investigated after overexpression in planta. visualizing effector delivery during infection is challenging due to the plant cell wall, autofluorescence, and low effector abundance. here, we used a gfp strand system ...201728600390
correction to biochemical and spectroscopic characterization of the non-heme fe(ii)- and 2-oxoglutarate-dependent ethylene-forming enzyme from pseudomonas syringae pv. phaseolicola pk2. 201728590751
surface inoculation and quantification of pseudomonas syringae population in the arabidopsis leaf apoplast.bacterial pathogens must enter the plant tissue in order to cause a successful infection. foliar bacterial pathogens that are not able to directly penetrate the plant epidermis rely on wounds or natural openings to internalize leaves. this protocol describes a procedure to estimate the population size of pseudomonas syringae in the leaf apoplast after surface inoculation of arabidopsis rosettes.201728573169
genetic interaction between arabidopsis qpm3.1 locus and bacterial effector gene hopw1-1 underlies natural variation in quantitative disease resistance to pseudomonas infection.wide quantitative variation in plant disease resistance across arabidopsis wild populations has been documented and the underlying mechanisms remain largely unknown. to investigate the genetic and molecular basis of this variation, arabidopsis recombinant inbred lines (rils) derived from aa-0 × col-0 and gie-0 × col-0 crosses were constructed and used for inoculation with pseudomonas syringae pathovars maculicola es4326 (es4326) and tomato dc3000 (dc3000). bacterial growth assays revealed contin ...201728523008
flagellin peptide flg22 gains access to long-distance trafficking in arabidopsis via its receptor, fls2.diverse pathogen-derived molecules, such as bacterial flagellin and its conserved peptide flg22, are recognized in plants via plasma membrane receptors and induce both local and systemic immune responses. the fate of such ligands was unknown: whether and by what mechanism(s) they enter plant cells and whether they are transported to distal tissues. we used biologically active fluorophore and radiolabeled peptides to establish that flg22 moves to distal organs with the closest vascular connection ...201728521013
a rapid seedling resistance assay identifies wild tomato lines that are resistant to pseudomonas syringae pv. tomato race 1.bacterial speck caused by pseudomonas syringae has historically been controlled by the pto/prf gene cluster. emerging strains like p. syringae pv. tomato race 1 overcome resistance conferred by pto/prf, and can cause serious crop loss under appropriate environmental conditions. we developed a rapid assay to screen wild tomato seedlings for resistance to p. syringae pv. tomato race 1. we established the seedling resistance assay using the well-characterized p. syringae pv. tomato race 0 strain, d ...201728517960
an hplc-based method to quantify coronatine production by bacteria.coronatine is a polyketide phytotoxin produced by several pathovars of the plant pathogenic bacterium pseudomonas syringae. it is one of the most important virulence factors determining the success of bacterial pathogenesis in the plant at both epiphytic and endophytic stages of the disease cycle. this protocol describes an optimized procedure to culture bacterial cells for coronatine production and to quantify the amount of coronatine secreted in the culture medium using an hplc-based method.201728516126
a calmodulin-like protein regulates plasmodesmal closure during bacterial immune responses.plants sense microbial signatures via activation of pattern recognition receptors (pprs), which trigger a range of cellular defences. one response is the closure of plasmodesmata, which reduces symplastic connectivity and the capacity for direct molecular exchange between host cells. plasmodesmal flux is regulated by a variety of environmental cues but the downstream signalling pathways are poorly defined, especially the way in which calcium regulates plasmodesmal closure. here, we identify that ...201728513846
functional characterization of key residues in regulatory proteins hrpg and hrpv of pseudomonas syringae pv. tomato dc3000.the plant pathogen pseudomonas syringae pv. tomato dc3000 uses a type iii secretion system (t3ss) to transfer effector proteins into the host. the expression of t3ss proteins is controlled by the hrpl σ factor. transcription of hrpl is σ(54)-dependent and bacterial enhancer-binding proteins hrpr and hrps coactivate the hrpl promoter. the hrpv protein imposes negative control upon hrpr and hrps through direct interaction with hrps. hrpg interacts with hrpv and relieves such negative control. the ...201728488468
complete sequence and comparative genomic analysis of eight native pseudomonas syringae plasmids belonging to the ppt23a family.the ppt23a family of plasmids appears to be indigenous to the plant pathogen pseudomonas syringae and these plasmids are widely distributed and widely transferred among pathovars of p. syringae and related species. ppt23a-family plasmids (pfps) are sources of accessory genes for their hosts that can include genes important for virulence and epiphytic colonization of plant leaf surfaces. the occurrence of repeated sequences including duplicated insertion sequences on pfps has made obtaining close ...201728486968
respective contribution of cml8 and cml9, two arabidopsis calmodulin-like proteins, to plant stress responses.in their natural environment, plants have to continuously face constraints such as biotic and abiotic stresses. to achieve their life cycle, plants have to perceive and interpret the nature, but also the strength of environmental stimuli to activate appropriate physiological responses. nowadays, it is well established that signaling pathways are crucial steps in the implementation of rapid and efficient plant responses such as genetic reprogramming. it is also reported that rapid raises in calci ...201728471263
use of ice-nucleating proteins to improve the performance of freeze-thaw valves in microfluidic devices.currently, reliable valving on integrated microfluidic devices fabricated from rigid materials is confined to expensive and complex methods. freeze-thaw valves (ftvs) can provide a low cost, low complexity valving mechanism, but reliable implementation of them has been greatly hindered by the lack of ice nucleation sites within the valve body's small volume. work to date has required very low temperatures (on the order of -40 °c or colder) to induce freezing without nucleation sites, making ftvs ...201728467855
selection and assessment of plant growth-promoting rhizobacteria for biological control of multiple plant diseases.a study was designed to screen individual strains of plant growth-promoting rhizobacteria (pgpr) for broad-spectrum disease suppression in vitro and in planta. in a preliminary screen, 28 of 196 strains inhibited eight different tested pathogens in vitro. in a secondary screen, these 28 strains showed broad spectrum antagonistic activity to six different genera of pathogens, and 24 of the 28 strains produced five traits reported to be related to plant growth promotion, including nitrogen fixatio ...201728440700
evading plant immunity: feedback control of the t3ss in pseudomonas syringae.microbes are responsible for over 10% of the global yield losses in staple crops such as wheat, rice, and maize. understanding the decision-making strategies that enable bacterial plant pathogens to evade the host immune system and cause disease is essential for managing their ever growing threat to food security. many utilise the needle-like type iii secretion system (t3ss) to suppress plant immunity, by injecting effector proteins that inhibit eukaryotic signalling pathways into the host cell ...201728435841
structural and stereoelectronic insights into oxygenase-catalyzed formation of ethylene from 2-oxoglutarate.ethylene is important in industry and biological signaling. in plants, ethylene is produced by oxidation of 1-aminocyclopropane-1-carboxylic acid, as catalyzed by 1-aminocyclopropane-1-carboxylic acid oxidase. bacteria catalyze ethylene production, but via the four-electron oxidation of 2-oxoglutarate to give ethylene in an arginine-dependent reaction. crystallographic and biochemical studies on the pseudomonas syringae ethylene-forming enzyme reveal a branched mechanism. in one branch, an appar ...201728420789
a signature of tree health? shifts in the microbiome and the ecological drivers of horse chestnut bleeding canker disease.host susceptibility to pathogens can be shaped by genetic, ecological, and evolutionary factors. the ability to predict the spread of disease therefore requires an integrated understanding of these factors, including effects of pests on pathogen growth and competition between pathogens and commensal microbiota for host resources. we examined interactions between the leaf-mining moth cameraria ohridella, the bacterial causal agent of bleeding canker disease pseudomonas syringae pv aesculi, and th ...201728418070
lsu network hubs integrate abiotic and biotic stress responses via interaction with the superoxide dismutase fsd2.in natural environments, plants often experience different stresses simultaneously, and adverse abiotic conditions can weaken the plant immune system. interactome mapping revealed that the low sulphur upregulated (lsu) proteins are hubs in an arabidopsis protein interaction network that are targeted by virulence effectors from evolutionarily diverse pathogens. here we show that lsu proteins are up-regulated in several abiotic and biotic stress conditions, such as nutrient depletion or salt stres ...201728207043
absence of phosphatidylcholine in bacterial membranes facilitates translocation of sec-dependent β-lactamase ampc from cytoplasm to periplasm in two pseudomonas strains.phosphatidylcholine (pc) is a rare membrane lipid in bacteria but crucial for virulence of various plant and animal pathogens. the pcs- mutant lacking pc in bacterial membranes of pseudomonas syringae pv. syringae van hall 1336 displayed more ampicillin resistance. ampicillin susceptibility tests gave an ic50 (half maximal inhibitory concentration) of 52 mg/ml for pseudomonas syringae pv. syringae van hall 1336, 53 mg/ml for the complemented strain 1336 rm (pcs-/+) and 90 mg/ml for the 1336 pcs- ...201627060745
natural variation in tomato reveals differences in the recognition of avrpto and avrptob effectors from pseudomonas syringae.the pto protein kinase from solanum pimpinellifolium interacts with pseudomonas syringae effectors avrpto or avrptob to activate effector-triggered immunity. the previously solved crystal structures of the avrpto-pto and avrptob-pto complexes revealed that pto binds each effector through both a shared and a unique interface. here we use natural variation in wild species of tomato to further investigate pto recognition of these two effectors. one species, solanum chmielewskii, was found to have m ...201626993968
production of the streptomyces scabies coronafacoyl phytotoxins involves a novel biosynthetic pathway with an f420 -dependent oxidoreductase and a short-chain dehydrogenase/reductase.coronafacoyl phytotoxins are secondary metabolites that are produced by various phytopathogenic bacteria, including several pathovars of the gram-negative bacterium pseudomonas syringae as well as the gram-positive potato scab pathogen streptomyces scabies. the phytotoxins are composed of the polyketide coronafacic acid (cfa) linked via an amide bond to amino acids or amino acid derivatives, and their biosynthesis involves the cfa and cfa-like gene clusters that are found in p. syringae and s. s ...201626991928
mapping the function of phytopathogen effectors.pseudomonas syringae secretes effectors from its type iii secretion system to infect plants. in this issue of cell host & microbe, guo et al. (2016) determine that the t3ss effector, hope1, targets calmodulin and the microtubule-associated protein map65-1 to subvert plant immunity.201626764591
structure-function relationship of a novel pr-5 protein with antimicrobial activity from soy hulls.an alkaline isoform of the pr-5 protein (designated gmolpc) has been purified from soybean hulls and identified by maldi-tof/tof-ms. gmolpc effectively inhibited in vitro the growth of phytophthora soja spore and pseudomonas syringae pv glycinea. the antimicrobial activity of gmolpc should be mainly ascribed to its high binding affinity with vesicles composed of dppg, (1,3)-β-d-glucans, and weak endo-(1,3)-β-d-glucanase activity. from the 3d models, predicted by the homology modeling, gmolpc con ...201626753535
pseudomonas syringae pv. phaseolicola isolated from weeds in bean crop fields.pseudomonas syringae pv. phaseolicola, the causative agent of halo blight in common bean (phaseolus vulgaris l.), was isolated from weeds associated with bean crops in spain. the bacterium was recovered from fumaria sp, mercurialis annua, solanum nigrum and sonchus oleraceus. ps. s. pv. phaseolicola had previously been isolated from leguminous plants and s. nigrum, but to our knowledge, this is the first time it was recovered from the other three species. the isolates were phenotypically and gen ...201626880144
analysis of the lmmunity-related oxidative bursts by a luminol-based assay.the rapid production of reactive oxygen species (ros) in response to biotic and abiotic cues is a conserved hallmark of plant responses. the detection and quantification of ros generation during immune responses is an excellent readout to analyze signaling triggered by the perception of pathogens. the assay described here is easy to employ and versatile, allowing its use in a multitude of variations. for example, ros production can be analyzed using different tissues including whole seedlings, r ...201626867635
the μ subunit of arabidopsis adaptor protein-2 is involved in effector-triggered immunity mediated by membrane-localized resistance proteins.endocytosis has been suggested to be important in the cellular processes of plant immune responses. however, our understanding of its role during effector-triggered immunity (eti) is still limited. we have previously shown that plant endocytosis, especially clathrin-coated vesicle formation at the plasma membrane, is mediated by the adaptor protein-2 (ap-2) complex and that loss of the μ subunit of ap-2 (ap2m) affects plant growth and floral organ development. here, we report that ap2m is requir ...201626828402
spatial and temporal variability in the potential of river water biofilms to degrade p-nitrophenol.in order to predict the fate of chemicals in the environment, a range of regulatory tests are performed with microbial inocula collected from environmental compartments to investigate the potential for biodegradation. the abundance and distribution of microbes in the environment is affected by a range of variables, hence diversity and biomass of inocula used in biodegradation tests can be highly variable in space and time. the use of artificial or natural biofilms in regulatory tests could enabl ...201627596822
root-mediated signal transmission of systemic acquired resistance against above-ground and below-ground pathogens.plants modulate defence signalling networks in response to various biotic stresses via inter-organ communications. the root-mediated transmission of systemic acquired resistance (sar) against soil-borne and air-borne plant pathogens from sar-induced plants to neighbouring plants subjected to local chemical and pathogen treatments was evaluated.201627555496
the bacteriophage-derived transcriptional regulator, lscr, activates the expression of levansucrase genes in pseudomonas syringae.synthesis of the exopolysaccharide levan occurs in the bacterial blight pathogen of soybean, pseudomonas syringae pv. glycinea pg4180, when this bacterium encounters moderate to high concentrations of sucrose inside its host plant. the process is mediated by the temperature-dependent expression and secretion of two levansucrases, lscb and lscc. previous studies showed the importance of a prophage-associated promoter element in driving the expression of levansucrase genes. herein, heterologous sc ...201627664099
activation-dependent destruction of a co-receptor by a pseudomonas syringae effector dampens plant immunity.the arabidopsis immune receptor fls2 and co-receptor bak1 perceive the bacterial flagellin epitope flg22 to activate plant immunity. to prevent this response, phytopathogenic bacteria deploy a repertoire of effector proteins to perturb immune signaling. however, the effector-induced perturbation is often sensed by the host, triggering another layer of immunity. we report that the pseudomonas syringae effector hopb1 acts as a protease to cleave immune-activated bak1. prior to activation, hopb1 co ...201627736646
exogenous n-acyl-homoserine lactones enhance the expression of flagella of pseudomonas syringae and activate defence responses in plants.in order to cope with pathogens, plants have evolved sophisticated mechanisms to sense pathogenic attacks and to induce defence responses. the n-acyl-homoserine lactone (ahl)-mediated quorum sensing in bacteria regulates diverse physiological processes, including those involved in pathogenicity. in this work, we study the interactions between ahl-producing transgenic tobacco plants and pseudomonas syringae pv. tabaci 11528 (p. syringae 11528). both a reduced incidence of disease and decrease in ...201627756102
a set of pcrs for rapid identification and characterization of pseudomonas syringae phylogroups.the aim of this study was to develop a rapid pcr-based method for the specific detection of individual phylogroups of the pseudomonas syringae complex.201626661140
expression of antimicrobial peptides under control of a camalexin-biosynthetic promoter confers enhanced resistance against pseudomonas syringae.in arabidopsis thaliana phytoalexin biosynthesis is tightly regulated. the camalexin biosynthetic gene cyp71b15/pad3 is highly expressed in response to pathogens and specific abiotic triggers, while constitutive expression is very low. based on this property we expressed artificial antimicrobial peptides under control of the cyp71b15 promoter avoiding potential toxic effects to the plant related to constitutive expression. significant and substantial growth inhibition of pseudomonas syringae was ...201626795461
the pseudomonas syringae type iii effectors avrrpm1 and avrrpt2 promote virulence dependent on the f-box protein coi1.type iii effectors avrrpm1 and avrrpt2 promote bacterial growth dependent on a coi1-mediated pathway in the absence of the rpm1 and rps2 resistance proteins. the type iii effectors, avrrpm1 and avrrpt2, promote bacterial virulence by suppressing host defense responses. the defense suppressing activities of avrrpm1 and avrrpt2 are best studied in the absence of the resistance proteins rpm1 and rps2, which induce defense responses to them. we tested whether the type iii effectors could modulate a ...201626795143
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