| arabidopsis thaliana serpins atsrp4 and atsrp5 negatively regulate stress-induced cell death and effector-triggered immunity induced by bacterial effector avrrpt2. | protease inhibitors and their cognate proteases regulate growth, development and defense. serine protease inhibitors (serpins) constitute a large family of genes in most metazoans and plants. drosophila necrotic (nec) gene and its homologues in the mammalian system are well-characterized serpins, which play a role in regulating proteases that participate in cell death pathways. although the arabidopsis genome contains several serpin homologs, biological function is not known for most of them. he ... | 2017 | 27709637 |
| 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 ... | 2016 | 27664099 |
| idl6-hae/hsl2 impacts pectin degradation and resistance to pseudomonas syringae pv tomato dc3000 in arabidopsis leaves. | plant cell walls undergo dynamic structural and chemical changes during plant development and growth. floral organ abscission and lateral root emergence are both accompanied by cell-wall remodeling, which involves the inflorescence deficient in abscission (ida)-derived peptide and its receptors, haesa (hae) and haesa-like2 (hsl2). plant cell walls also act as barriers against pathogenic invaders. thus, the cell-wall remodeling during plant development could have an influence on plant resistance ... | 2017 | 27618493 |
| 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 ... | 2016 | 27596822 |
| 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. | 2016 | 27555496 |
| a proposal for a genome similarity-based taxonomy for plant-pathogenic bacteria that is sufficiently precise to reflect phylogeny, host range, and outbreak affiliation applied to pseudomonas syringae sensu lato as a proof of concept. | taxonomy of plant pathogenic bacteria is challenging because pathogens of different crops often belong to the same named species but current taxonomy does not provide names for bacteria below the subspecies level. the introduction of the host range-based pathovar system in the 1980s provided a temporary solution to this problem but has many limitations. the affordability of genome sequencing now provides the opportunity for developing a new genome-based taxonomic framework. we already proposed t ... | 2017 | 27552324 |
| multiple xanthomonas euvesicatoria type iii effectors inhibit flg22-triggered immunity. | xanthomonas euvesicatoria is the causal agent of bacterial spot disease in pepper and tomato. x. euvesicatoria bacteria interfere with plant cellular processes by injecting effector proteins into host cells through the type iii secretion (t3s) system. about 35 t3s effectors have been identified in x. euvesicatoria 85-10, and a few of them were implicated in suppression of pattern-triggered immunity (pti). we used an arabidopsis thaliana pathogen-free protoplast-based assay to identify x. euvesic ... | 2016 | 27529660 |
| a set of pcrs for rapid identification and characterization of pseudomonas syringae phylogroups. | | 2016 | 27528015 |
| structure of a pathogen effector reveals the enzymatic mechanism of a novel acetyltransferase family. | effectors secreted by the type iii secretion system are essential for bacterial pathogenesis. members of the yersinia outer-protein j (yopj) family of effectors found in diverse plant and animal pathogens depend on a protease-like catalytic triad to acetylate host proteins and produce virulence. however, the structural basis for this noncanonical acetyltransferase activity remains unknown. here, we report the crystal structures of the yopj effector hopz1a, produced by the phytopathogen pseudomon ... | 2016 | 27525589 |
| pseudomonas syringae differentiates into phenotypically distinct subpopulations during colonization of a plant host. | bacterial microcolonies with heterogeneous sizes are formed during colonization of phaseolus vulgaris by pseudomonas syringae. heterogeneous expression of structural and regulatory components of the p. syringae type iii secretion system (t3ss), essential for colonization of the host apoplast and disease development, is likewise detected within the plant apoplast. t3ss expression is bistable in the homogeneous environment of nutrient-limited t3ss-inducing medium, suggesting that subpopulation for ... | 2016 | 27516206 |
| bacterial ice nucleation in monodisperse d2o and h2o-in-oil emulsions. | ice nucleation is of fundamental significance in many areas, including atmospheric science, food technology, and cryobiology. in this study, we investigated the ice-nucleation characteristics of picoliter-sized drops consisting of different d2o and h2o mixtures with and without the ice-nucleating bacteria pseudomonas syringae. we also studied the effects of commonly used cryoprotectants such as ethylene glycol, propylene glycol, and trehalose on the nucleation characteristics of d2o and h2o mixt ... | 2016 | 27495973 |
| a low frequency persistent reservoir of a genomic island in a pathogen population ensures island survival and improves pathogen fitness in a susceptible host. | the co-evolution of bacterial plant pathogens and their hosts is a complex and dynamic process. host resistance imposes stress on invading pathogens that can lead to changes in the bacterial genome enabling the pathogen to escape host resistance. we have observed this phenomenon with the plant pathogen pseudomonas syringae pv. phaseolicola where isolates that have lost the genomic island pphgi-1 carrying the effector gene avrpphb from its chromosome are infective against previously resistant pla ... | 2016 | 27491006 |
| pathogen infection and morc proteins affect chromatin accessibility of transposable elements and expression of their proximal genes in arabidopsis. | to assess the role of morc1 in epigenetics in relation to plant immunity, genome-wide chromatin accessibility was compared between mock- or pseudomonas syringae pv. tomato-inoculated wild type (wt) arabidopsis, the morc1/2 double mutant, or both. most changes in chromatin accessibility, scored by dnase i hypersensitive sites (dhss), were located in the promoters of genes and transposable elements (tes). comparisons between morc1/2 and wt receiving the same treatment revealed differential dhss (d ... | 2016 | 27482822 |
| cooperative functioning between phenylalanine ammonia lyase and isochorismate synthase activities contributes to salicylic acid biosynthesis in soybean. | salicylic acid (sa), an essential regulator of plant defense, is derived from chorismate via either the phenylalanine ammonia lyase (pal) or the isochorismate synthase (ics) catalyzed steps. the ics pathway is thought to be the primary contributor of defense-related sa, at least in arabidopsis. we investigated the relative contributions of pal and ics to defense-related sa accumulation in soybean (glycine max). soybean plants silenced for five pal isoforms or two ics isoforms were analyzed for s ... | 2016 | 27411159 |
| the arabidopsis thaliana lectin receptor kinase lecrk-i.9 is required for full resistance to pseudomonas syringae and affects jasmonate signalling. | on microbial attack, plants can detect invaders and activate plant innate immunity. for the detection of pathogen molecules or cell wall damage, plants employ receptors that trigger the activation of defence responses. cell surface proteins that belong to large families of lectin receptor kinases are candidates to function as immune receptors. here, the function of lecrk-i.9 (at5g60300), a legume-type lectin receptor kinase involved in cell wall-plasma membrane contacts and in extracellular atp ... | 2016 | 27399963 |
| metabolomic analysis reveals the relationship between azi1 and sugar signaling in systemic acquired resistance of arabidopsis. | the function of azi1 in systemic acquired resistance of arabidopsis was confirmed by investigation of the phenotypic features of wild-type col-0, azi1 t-dna knockout and azi1 overexpressing plants after infection with virulent and avirulent pseudomonas syringae. real-time quantitative pcr and northern blotting analyses showed that the transcript abundances of pr genes increased significantly in local and systemic leaves of wild-type col-0 and azi1 overexpressing plants challenged with avirulent ... | 2016 | 27337039 |
| algu controls expression of virulence genes in pseudomonas syringae pv. tomato dc3000. | plant-pathogenic bacteria are able to integrate information about their environment and adjust gene expression to provide adaptive functions. algu, an extracytoplasmic function (ecf) sigma factor encoded by pseudomonas syringae, controls expression of genes for alginate biosynthesis and genes involved with resisting osmotic and oxidative stress. algu is active while these bacteria are associated with plants, where its presence supports bacterial growth and disease symptoms. we found that algu is ... | 2016 | 27325679 |
| the arabidopsis malectin-like/lrr-rlk ios1 is critical for bak1-dependent and bak1-independent pattern-triggered immunity. | plasma membrane-localized pattern recognition receptors (prrs) such as flagellin sensing2 (fls2), ef-tu receptor (efr), and chitin elicitor receptor kinase1 (cerk1) recognize microbe-associated molecular patterns (mamps) to activate pattern-triggered immunity (pti). a reverse genetics approach on genes responsive to the priming agent β-aminobutyric acid (baba) revealed impaired oomycete susceptibility1 (ios1) as a critical pti player. arabidopsis thaliana ios1 mutants were hypersusceptible to ps ... | 2016 | 27317676 |
| getting to pti of bacterial rnas: triggering plant innate immunity by extracellular rnas from bacteria. | defense against diverse biotic and abiotic stresses requires the plant to distinguish between self and non-self signaling molecules. pathogen/microbe-associated molecular patterns (pamps/mamps) are pivotal for triggering innate immunity in plants. unlike in animals and humans, the precise roles of nucleic acids in plant innate immunity are unclear. we therefore investigated the effects of infiltration of total pseudomonas syringae pv. tomato dc3000 (pto dc3000) rnas into arabidopsis plants. the ... | 2016 | 27301792 |
| selective photoreceptor gene knock-out reveals a regulatory role for the growth behavior of pseudomonas syringae. | the plant pathogen pseudomonas syringae (ps) is a well-established model organism for bacterial infection of plants. the genome sequences of two pathovars, pv. syringae and pv. tomato, revealed one gene encoding a blue and two genes encoding red/far red light-sensing photoreceptors. continuing former molecular characterization of the photoreceptor proteins, we here report selective photoreceptor gene disruption for pv. tomato aiming at identification of potentially regulatory functions of these ... | 2016 | 27289014 |
| wide distribution of airborne ice-nucleation active pseudomonas syringae in agricultural environments. | pseudomonas syringae, a phytopathogen with a wide host range, inhabits various environments. among these habitats, air is an important transport environment for microbes, allowing them to disperse over long distances; however, information on the distribution and composition of airborne p. syringae is limited. here, we report the isolation of several groups of airborne p. syringae in japan. since 2013, we have trapped 43 strains of airborne p. syringae species complex, most of which were ice-nucl ... | 2016 | 27247081 |
| the type iii effector avrxccb in xanthomonas campestris pv. campestris targets putative methyltransferases and suppresses innate immunity in arabidopsis. | xanthomonas campestris pv. campestris (xcc) causes black rot, one of the most important diseases of brassica crops worldwide. the type iii effector inventory plays important roles in the virulence and pathogenicity of the pathogen. however, little is known about the virulence function(s) of the putative type iii effector avrxccb in xcc. here, we investigated the immune suppression ability of avrxccb and the possible underlying mechanisms. avrxccb was demonstrated to be secreted in a type iii sec ... | 2016 | 27241588 |
| proteomics and functional analyses of arabidopsis nitrilases involved in the defense response to microbial pathogens. | proteomics and functional analyses of the arabidopsis - pseudomonas syringae pv. tomato interactions reveal that arabidopsis nitrilases are required for plant defense and r gene-mediated resistant responses to microbial pathogens. a high-throughput in planta proteome screen has identified arabidopsis nitrilase 2 (atnit2), which was de novo-induced by pseudomonas syringae pv. tomato (pst) infection. the atnit2, atnit3, and atnit4 genes, but not atnit1, were distinctly induced in arabidopsis leave ... | 2016 | 27095107 |
| detection of peroxynitrite in plants exposed to bacterial infection. | peroxynitrite is a highly reactive derivative of nitric oxide (no) which is gaining attention in the plant biology community because it may play a role in no signaling during biotic stress. peroxynitrite can react with many different biomolecules, but its ability to nitrate the tyrosine residues of proteins is particularly important because this may regulate defense signaling in response to pathogens. the analysis of peroxynitrite levels in the context of its proposed defense role requires an ac ... | 2016 | 27094421 |
| the hopf family of pseudomonas syringae type iii secreted effectors. | pseudomonas syringae is a bacterial phytopathogen that utilizes the type iii secretion system to inject effector proteins into plant host cells. pseudomonas syringae can infect a wide range of plant hosts, including agronomically important crops such as tomatoes and beans. the ability of p. syringae to infect such numerous hosts is caused, in part, by the diversity of effectors employed by this phytopathogen. over 60 different effector families exist in p. syringae; one such family is hopf, whic ... | 2017 | 27061875 |
| 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- ... | 2016 | 27060745 |
| 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 ... | 2016 | 26993968 |
| 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 ... | 2016 | 26991928 |
| divorcing strain classification from species names. | confusion about strain classification and nomenclature permeates modern microbiology. although taxonomists have traditionally acted as gatekeepers of order, the numbers of, and speed at which, new strains are identified has outpaced the opportunity for professional classification for many lineages. furthermore, the growth of bioinformatics and database-fueled investigations have placed metadata curation in the hands of researchers with little taxonomic experience. here i describe practical chall ... | 2016 | 26947794 |
| elongator plays a positive role in exogenous nad-induced defense responses in arabidopsis. | extracellular nad is emerging as an important signal molecule in animal cells, but its role in plants has not been well-established. although it has been shown that exogenous nad(+) activates defense responses in arabidopsis, components in the exogenous nad(+)-activated defense pathway remain to be fully discovered. in a genetic screen for mutants insensitive to exogenous nad(+) (ien), we isolated a mutant named ien2. map-based cloning revealed that ien2 encodes elongata3 (elo3)/atelp3, a subuni ... | 2016 | 26926998 |
| phytopathogen genome announcement: draft genome sequences of 62 pseudomonas syringae type and pathotype strains. | pseudomonas syringae is a diverse species-complex that includes many important crop pathogens. here, we report the draft genomes of 62 type and pathotype strains, which provide a genomic reference for the diversity of this species complex and will contribute to the elucidation of the genomic basis of pathogenicity and host specificity. | 2016 | 26883489 |
| 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 ... | 2016 | 26880144 |
| 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 ... | 2016 | 26867635 |
| 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 ... | 2016 | 26828402 |
| bri1-ems-suppressor 1 gain-of-function mutant shows higher susceptibility to necrotrophic fungal infection. | brassinosteroids (brs) are plant-specific steroids that are involved in plant growth and defense responses. however, the exact roles of br in plant defense are unclear. we used the bes1-d gain-of-function mutant to define the underlying relationship between plant growth and defense through br signaling and innate immunity. in bes1-d, further downstream component bes1 transcription factor is stabilized, leading to the activation of br signaling. previous reports on bes1 target genes showed that a ... | 2016 | 26809089 |
| regulatory and functional aspects of indolic metabolism in plant systemic acquired resistance. | tryptophan-derived, indolic metabolites possess diverse functions in arabidopsis innate immunity to microbial pathogen infection. here, we investigate the functional role and regulatory characteristics of indolic metabolism in arabidopsis systemic acquired resistance (sar) triggered by the bacterial pathogen pseudomonas syringae. indolic metabolism is broadly activated in both p. syringae-inoculated and distant, non-inoculated leaves. at inoculation sites, camalexin, indol-3-ylmethylamine (i3a), ... | 2016 | 26802249 |
| 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 ... | 2016 | 26795461 |
| 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 ... | 2016 | 26795143 |
| detection and characterization of pseudomonas syringae pv. actinidifoliorum in kiwifruit in spain. | bacterial canker of kiwifruit caused by pseudomonas syringae pv. actinidiae (psa) is currently the major threat to its commercial production worldwide. in 2011, the most virulent type (psa3) was detected for the first time in northwest-spain, in the province of pontevedra. in 2013 surveys, leaves and flower buds with mild symptoms were observed in actinidia deliciosa 'hayward' vines in an orchard at the province of a coruña, suggesting the presence of p. syringae pv. actinidifoliorum (psaf). | 2015 | 26768357 |
| a bacterial effector co-opts calmodulin to target the plant microtubule network. | the bacterial pathogen pseudomonas syringae depends on effector proteins secreted by its type iii secretion system for the pathogenesis of plants. the majority of these effector proteins are known suppressors of immunity, but their plant targets remain elusive. using arabidopsis thaliana as a model host, we report that the hope1 effector uses the host calcium sensor, calmodulin (cam), as a co-factor to target the microtubule-associated protein 65 (map65), an important component of the microtubul ... | 2016 | 26764598 |
| 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. | 2016 | 26764591 |
| 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 ... | 2016 | 26753535 |
| transcriptional control of quorum sensing and associated metabolic interactions in pseudomonas syringae strain b728a. | pseudomonas syringae pv. syringae cell densities fluctuate regularly during host plant colonization. previously we identified nine genes dependent on the quorum-sensing-associated luxr homolog ahlr during epiphytic and apoplastic stages of host colonization. yet their contributions to host colonization remain obscure, despite ahlr regulon presence within and beyond the p. syringae pan-genome. to elucidate ahir regulon member functions, we characterized their regulation, interactions with each ot ... | 2016 | 26713670 |
| the pepper gna-related lectin and pan domain protein gene, caglp1, is required for plant cell death and defense signaling during bacterial infection. | carbohydrate-binding proteins, commonly referred to as lectins or agglutinins, function in defense responses to microbial pathogens. pepper (capsicum annuum) gna-related lectin and pan-domain protein gene caglp1 was isolated and functionally characterized from pepper leaves infected with xanthomonas campestris pv. vesicatoria (xcv). caglp1 contained an amine-terminus prokaryotic membrane lipoprotein lipid attachment site, a galanthus nivalis agglutinin (gna)-related lectin domain responsible for ... | 2015 | 26706081 |
| 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. | 2016 | 26661140 |
| the pathogenicity factor hrpf interacts with hrpa and hrpg to modulate type iii secretion system (t3ss) function and t3ss expression in pseudomonas syringae pv. averrhoi. | to ensure the optimal infectivity on contact with host cells, pathogenic pseudomonas syringae has evolved a complex mechanism to control the expression and construction of the functional type iii secretion system (t3ss) that serves as a dominant pathogenicity factor. in this study, we showed that the hrpf gene of p. syringae pv. averrhoi, which is located upstream of hrpg, encodes a t3ss-dependent secreted/translocated protein. mutation of hrpf leads to the loss of bacterial ability on elicitati ... | 2016 | 26638129 |
| isolation and characterization of bacteriophages against pseudomonas syringae pv. actinidiae causing bacterial canker disease in kiwifruit. | pseudomonas syringae pv. actinidiae causes bacterial canker disease in kiwifruit. owing to the prohibition of agricultural antibiotic use in major kiwifruit-cultivating countries, alternative methods need to be developed to manage this disease. bacteriophages are viruses that specifically infect target bacteria and have recently been reconsidered as potential biological control agents for bacterial pathogens owing to their specificity in terms of host range. in this study, we isolated bacterioph ... | 2016 | 26628254 |
| isolation and identification of pseudomonas syringae facilitated by a pcr targeting the whole p. syringae group. | we present a reliable pcr-based method to avoid the biases related to identification based on the conventional phenotypes currently used in the identification of pseudomonas syringae sensu lato, a ubiquitous environmental bacterium including plant pathogens. we identified a dna target suitable for this purpose by applying a comparative genomic pipeline to pseudomonas genomes. we designed primers and developed pcr conditions that led to a clean and strong pcr product from 97% of the 185 strains o ... | 2016 | 26610434 |
| competitive index: mixed infection-based virulence assays for genetic analysis in pseudomonas syringae-plant interactions. | when studying bacterial plant pathogens, the genetic analysis of the contribution of virulence factors to the infection process has traditionally been hindered by their high degree of functional redundancy. in recent years, it has become clear that the use of competitive index in mixed infections provides an accurate and sensitive manner of establishing virulence phenotypes for mutants for which other assays have failed. such increases in sensitivity and accuracy are due to the direct comparison ... | 2016 | 26577792 |
| amrz regulates cellulose production in pseudomonas syringae pv. tomato dc3000. | in pseudomonas syringae pv. tomato dc3000, the second messenger c-di-gmp has been previously shown to stimulate pellicle formation and cellulose biosynthesis. a screen for genes involved in cellulose production under high c-di-gmp intracellular levels led to the identification of insertions in two genes, wssb and wsse, belonging to the pto dc3000 cellulose biosynthesis operon wssabcdefghi. interestingly, beside cellulose-deficient mutants, colonies with a rougher appearance than the wild type al ... | 2016 | 26564578 |
| pseudomonas syringae pv. tomato oxyr is required for virulence in tomato and arabidopsis. | reactive oxygen species (ros) have been shown to have a crucial role in plant defense responses and signaling pathways. in addition, ros also have direct toxicity against pathogens. however, the molecular mechanisms of plant ros in the direct effects against pathogens is still unclear. to investigate the function of plant ros in the interactions of plant and bacterial pathogens, we focused on oxyr, encoding an oxidative stress-regulated transcription factor in pseudomonas syringae pv. tomato dc3 ... | 2016 | 26554736 |
| the hexapeptide repeated segment liagy is a hot spot of aggregation of the pseudomonas syringae ice nucleation protein. | ice nucleation proteins (inps) form oligomeric structures by self-assembly and aggregation. we looked for the presence of potential aggregating sequences inside the inp from pseudomonas syringae by a computational approach with the aggrescan, fomdamyloid and tango softwares. a total of 38 hot spots of aggregation were predicted in the inp sequence: 7 localized in the nterminal domain, 2 in the c-terminal region, 28 in the highly repetitive central (hrc) region and 1 shared between the hrc and th ... | 2016 | 26548995 |
| calcium-dependent protein kinase (cdpk) and cdpk-related kinase (crk) gene families in tomato: genome-wide identification and functional analyses in disease resistance. | calcium-dependent protein kinases (cdpks) and cdpk-related kinases (crks) play multiple roles in plant. nevertheless, genome-wide identification of these two families is limited to several plant species, and role of crks in disease resistance remains unclear. in this study, we identified the cdpk and crk gene families in genome of the economically important crop tomato (solanum lycopersicum l.) and analyzed their function in resistance to various pathogens. twenty-nine cdpk and six crk genes wer ... | 2016 | 26520101 |
| from filaments to function: the role of the plant actin cytoskeleton in pathogen perception, signaling and immunity. | the eukaryotic actin cytoskeleton is required for numerous cellular processes, including cell shape, development and movement, gene expression and signal transduction, and response to biotic and abiotic stress. in recent years, research in both plants and animal systems have described a function for actin as the ideal surveillance platform, linking the function and activity of primary physiological processes to the immune system. in this review, we will highlight recent advances that have define ... | 2016 | 26514830 |
| membrane-associated ubiquitin ligase saul1 suppresses temperature- and humidity-dependent autoimmunity in arabidopsis. | plants have evolved elaborate mechanisms to regulate pathogen defense. imbalances in this regulation may result in autoimmune responses that are affecting plant growth and development. in arabidopsis, saul1 encodes a plant u-box ubiquitin ligase and regulates senescence and cell death. here, we show that saul1-1 plants exhibit characteristics of an autoimmune mutant. a decrease in relative humidity or temperature resulted in reduced growth and systemic lesioning of saul1-1 rosettes. these physio ... | 2016 | 26505534 |
| bacterial rnas activate innate immunity in arabidopsis. | the common molecular patterns of microbes play a critical role in the regulation of plant innate immunity. however, little is known about the role of nucleic acids in this process in plants. we pre-infiltrated arabidopsis leaves with total rnas from pseudomonas syringae pv. tomato dc3000 (pto dc3000) and subsequently inoculated these plants with the same bacterial cells. total pto dc3000 rnas pre-infiltrated into arabidopsis leaves elicited plant immune responses against pto dc3000. however, she ... | 2016 | 26499893 |
| bacterial leaf infiltration assay for fine characterization of plant defense responses using the arabidopsis thaliana-pseudomonas syringae pathosystem. | in the absence of specialized mobile immune cells, plants utilize their localized programmed cell death and systemic acquired resistance to defend themselves against pathogen attack. the contribution of a specific arabidopsis gene to the overall plant immune response can be specifically and quantitatively assessed by assaying the pathogen growth within the infected tissue. for over three decades, the hemibiotrophic bacterium pseudomonas syringae pv. maculicola es4326 (psm es4326) has been widely ... | 2015 | 26485301 |
| functional analysis of ntmpk2 uncovers its positive role in response to pseudomonas syringae pv. tomato dc3000 in tobacco. | mitogen-activated protein kinase cascades are highly conserved signaling modules downstream of receptors/sensors and play pivotal roles in signaling plant defense against pathogen attack. extensive studies on arabidopsis mpk4 have implicated that the map kinase is involved in multilayered plant defense pathways. in this study, we identified tobacco ntmpk2 as an ortholog of atmpk4. transgenic tobacco overexpressing ntmpk2 markedly enhances resistance to pseudomonas syringae pv. tomato dc3000 (pst ... | 2016 | 26482478 |
| enhancement of thiamin content in arabidopsis thaliana by metabolic engineering. | thiamin is an essential nutrient in the human diet. severe thiamin deficiency leads to beriberi, a lethal disease which is common in developing countries. thiamin biofortification of staple food crops is a possible strategy to alleviate thiamin deficiency-related diseases. in plants, thiamin plays a role in the response to abiotic and biotic stresses, and data from the literature suggest that boosting thiamin content could increase resistance to stresses. here, we tested an engineering strategy ... | 2015 | 26454882 |
| using the plant vacuole as a biological system to investigate the functional properties of exogenous channels and transporters. | plant cells possess a large intracellular compartment that animal cells do not, the central vacuole, which has been investigated for a long time. the central vacuole can occupy up to 90% of the cellular volume and, differently from intracellular organelles from animal cells such as lysosomes or endosomes, it is easy to isolate. because of its large dimension (up to 40 μm diameter) it can be successfully studied using the classical patch-clamp technique. following the idea that the vacuolar membr ... | 2016 | 26431786 |
| the hrp pathogenicity island of pseudomonas syringae pv. tomato dc3000 is induced by plant phenolic acids. | plants produce a wide array of antimicrobial compounds, such as phenolic compounds, to combat microbial pathogens. the hrp pai is one of the major virulence factors in the plant pathogen, pseudomonas syringae. a major role of hrp pai is to disable the plant defense system during bacterial invasion. we examined the influence of phenolic compounds on hrp pai gene expression at low and high concentrations. there was approximately 2.5 times more hrpa and hrpz mrna in ptodc3000 that was grown in mini ... | 2015 | 26428924 |
| functional analysis of the aefr mutation and identification of its binding site in pseudomonas syringae pv. tabaci 11528. | the tetr family transcriptional regulator aefr contributes to the regulation of the quorum-sensing system. however, the role of aefr in the regulatory network of the phytopathogen pseudomonas syringae pathovars is not known. in this study, the phenotype of a p. syringae pv. tabaci 11528 aefr deletion mutant strain was examined. the aefr gene expression and aefr dna-binding affinity were examined by quantitative real-time polymerase chain reaction and electrophoretic mobility shift assay, respect ... | 2015 | 26376742 |
| the decoy substrate of a pathogen effector and a pseudokinase specify pathogen-induced modified-self recognition and immunity in plants. | in plants, host response to pathogenic microbes is driven both by microbial perception and detection of modified-self. the xanthomonas campestris effector protein avrac/xopac uridylylates the arabidopsis bik1 kinase to dampen basal resistance and thereby promotes bacterial virulence. here we show that pbl2, a paralog of bik1, is similarly uridylylated by avrac. however, in contrast to bik1, pbl2 uridylylation is specifically required for host recognition of avrac to trigger immunity, but not avr ... | 2015 | 26355215 |
| identification of pseudomonas syringae pv. actinidiae strains causing bacterial canker of kiwifruit in the anhui province of china, and determination of their streptomycin sensitivities. | bacterial canker, caused by pseudomonas syringae pv. actinidiae, is one of the most severe diseases of kiwifruit. it has become an international pandemic and threatens the sustainable development of kiwifruit production in all main kiwi-growing regions worldwide. streptomycin has been the major bactericide for the control of kiwifruit canker, especially in anhui province, one of the main kiwifruit production regions in china. however, until now, no studies on the baseline sensitivity to streptom ... | 2015 | 26345745 |
| the arabidopsis lectin euls3 is involved in stomatal closure. | plants synthesize carbohydrate binding proteins in response to adverse environmental conditions such as drought, heat, pathogen attack, etc. the arabidopsis euls3 lectin (referred to as aratheuls3, encoded by at2g39050) has recently been linked to the drought stress response. in this study, endogenous binding partners for this protein have been investigated. tandem affinity purifications and mass spectrometry analyses allowed the identification of two putative interacting proteins, embryo-specif ... | 2015 | 26259197 |
| the pepper phosphoenolpyruvate carboxykinase capepck1 is involved in plant immunity against bacterial and oomycete pathogens. | phosphoenolpyruvate carboxykinase, a member of the lyase family, is involved in the metabolic pathway of gluconeogenesis in organisms. although the major function of pepck in gluconeogenesis is well established, it is unclear whether this enzyme is involved in plant immunity. here, we isolated and identified the pepper (capsicum annuum) pepck (capepck1) gene from pepper leaves infected with xanthomonas campestris pv. vesicatoria (xcv). capepck1 was strongly expressed in pepper leaves during the ... | 2015 | 26233534 |
| tolerance of an antarctic bacterium to multiple environmental stressors. | a population of cold-tolerant antarctic bacteria was screened for their ability to tolerate other environmental stress factors. besides low temperature, they were predominantly found to be tolerant to alkali. attempt was also made to postulate a genetic basis of their multistress-tolerance. transposon mutagenesis of an isolate pseudomonas syringae lz4w was performed, and mutants with delayed growth at low temperature were further screened for sensitivity to some other stress factors. a number of ... | 2015 | 26198412 |
| visualizing the relevance of bacterial blue- and red-light receptors during plant-pathogen interaction. | the foliar pathogen pseudomonas syringae pv. tomato dc3000 (pst) leads to consistent losses in tomato crops, urging to multiply investigations on the physiological bases for its infectiveness. as other p. syringae pathovars, pst is equipped with photoreceptors for blue and red light, mimicking the photosensing ability of host plants. in this work we have investigated pst strains lacking the genes for a blue-light sensing protein (pstlov), for a bacteriophytochrome (pstbph1) or for heme-oxygenase ... | 2015 | 26147514 |
| ltp3 contributes to disease susceptibility in arabidopsis by enhancing abscisic acid (aba) biosynthesis. | several plant lipid transfer proteins (ltps) act positively in plant disease resistance. here, we show that ltp3 (at5g59320), a pathogen and abscisic acid (aba)-induced gene, negatively regulates plant immunity in arabidopsis. the overexpression of ltp3 (ltp3-ox) led to an enhanced susceptibility to virulent bacteria and compromised resistance to avirulent bacteria. on infection of ltp3-ox plants with pseudomonas syringae pv. tomato, genes involved in aba biosynthesis, nced3 and aao3, were highl ... | 2016 | 26123657 |
| cellulose production in pseudomonas syringae pv. syringae: a compromise between epiphytic and pathogenic lifestyles. | genome sequencing and annotation have revealed a putative cellulose biosynthetic operon in the strain pseudomonas syringae pv. syringae umaf0158, the causal agent of bacterial apical necrosis. bioinformatics analyses and experimental methods were used to confirm the functionality of the cellulose biosynthetic operon. in addition, the results showed the contribution of the cellulose operon to important aspects of p. syringae pv. syringae biology, such as the formation of biofilms and adhesion to ... | 2015 | 26109133 |
| the chromatin remodeler splayed negatively regulates snc1-mediated immunity. | snc1 (suppressor of npr1, constitutive 1) is one of a suite of intracellular arabidopsis nod-like receptor (nlr) proteins which, upon activation, result in the induction of defense responses. however, the molecular mechanisms underlying nlr activation and the subsequent provocation of immune responses are only partially characterized. to identify negative regulators of nlr-mediated immunity, a forward genetic screen was undertaken to search for enhancers of the dwarf, autoimmune gain-of-function ... | 2015 | 26063389 |
| changes in the proteome of pad2-1, a glutathione depleted arabidopsis mutant, during pseudomonas syringae infection. | the involvement of glutathione (gsh) in plant defense against pathogen invasion is an established fact. however, the molecular mechanism conferring this tolerance remains to be explored. here, proteomic analysis of pad2-1, an arabidopsis thaliana gsh-depleted mutant, in response to pseudomonas syringae infection has been performed to explore the intricate position of gsh in defense against biotrophic pathogens. the pad2-1 mutant displayed severe susceptibility to p. syringae infection compared t ... | 2015 | 26032221 |
| arabidopsis abscisic acid receptors play an important role in disease resistance. | stomata are natural pores of plants and constitute the entry points for water during transpiration. however, they also facilitate the ingress of potentially harmful bacterial pathogens. the phytohormone abscisic acid (aba) plays a pivotal role in protecting plants against biotic stress, by regulating stomatal closure. in the present study, we investigated the mechanism whereby aba influences plant defense responses to pseudomonas syringae pv. tomato (pst) dc3000, which is a virulent bacterial pa ... | 2015 | 25969135 |
| melatonin regulates carbohydrate metabolism and defenses against pseudomonas syringae pv. tomato dc3000 infection in arabidopsis thaliana. | melatonin has been reported to promote plant growth and development. our experiments with arabidopsis thaliana showed that exogenous applications of this molecule mediated invertase inhibitor (c/vif)-regulated invertase activity and enhanced sucrose metabolism. hexoses were accumulated in response to elevated activities by cell wall invertase (cwi) and vacuolar invertase (vi). analyses of sugar metabolism-related genes revealed differential expression during plant development that was modulated ... | 2015 | 25958775 |
| salicylic acid and cysteine contribute to arbutin-induced alleviation of angular leaf spot disease development in cucumber. | arbutin induced suppression of angular leaf spot disease in cucumber resulting from lower populations of pseudomonas syringae pv lachrymans in the infected tissues. this study provides insight into mechanisms that may potentially account for this effect. in the absence of the pathogen, exogenous arbutin-induced expression of pr1, the marker of salicylic acid signaling, increased the content of salicylic acid and modulated the cysteine pool. this suggested that arbutin promoted cucumber plants to ... | 2015 | 25955697 |
| the zinc-binding nuclear protein hipp3 acts as an upstream regulator of the salicylate-dependent plant immunity pathway and of flowering time in arabidopsis thaliana. | biotic and abiotic stress responses of plants are linked to developmental programs. proteins involved in different signaling pathways are the molecular basis of this concerted interplay. in our study, we show that arabidopsis thaliana heavy metal-associated isoprenylated plant protein3 (hipp3; at5g60800) acts as an upstream regulator of stress- and development-related regulatory networks. localization, metal-binding and stress-responsive gene expression of hipp3 were analyzed via microscopy, pro ... | 2015 | 25913773 |
| synthesis, characterization, and application of microbe-triggered controlled-release kasugamycin-pectin conjugate. | the controlled and targeted release of pesticides with high water solubility has been a challenge for integrated pest management. in this paper, kasugamycin, an antibiotic broadly used in plant disease control, was covalently conjugated to pectin to form a kasugamycin-pectin conjugate by an amide bond. the conjugate was structurally characterized by fourier transform infrared spectroscopy, ultraviolet spectrophotometry, and thermal gravimetric analysis. the results showed that the conjugate was ... | 2015 | 25876441 |
| the co-4 locus on chromosome pv08 contains a unique cluster of 18 cok-4 genes and is regulated by immune response in common bean. | the common bean locus co - 4, traditionally referred to as an anthracnose-resistant gene, contains a cluster of predicted receptor-like kinases (cok-4 and crrlk1-like), and at least two of these kinases are co-regulated with the plant's basal immunity. genetic resistance to anthracnose, caused by the fungus colletotrichum lindemuthianum (sacc. and magnus) briosi and cavara, is conferred by major loci throughout the phaseolus vulgaris genome, named co. the complex co-4 locus was previously report ... | 2015 | 25805316 |
| functional genomics of tomato for the study of plant immunity. | tomato (solanum lycopersicum), along with many other economically valuable species, belongs to the solanaceae family. understanding how plants in this family defend themselves against pathogens offers the opportunity of improving yield and quality of their edible products. the use of functional genomics has contributed to this purpose through both traditional and recently developed techniques that allow determination of changes in transcript abundance during pathogen attack. such changes can imp ... | 2015 | 25797691 |
| antibacterial activity of essential oils mixture against psa. | pseudomonas syringae pv. actinidiae (psa) is the causal agent of bacterial canker of kiwifruit. it is very difficult to treat pandemic disease. the prolonged treatment with antibiotics, has resulted in failure and resistance and alternatives to conventional antimicrobial therapy are needed. the aim of our study was to analyse the phenotypic characteristics of psa, identify new substances from natural source i.e. essential oils (eos) able to contain the kiwifruit canker and investigate their pote ... | 2016 | 25782920 |
| arabidopsis ef-tu receptor enhances bacterial disease resistance in transgenic wheat. | perception of pathogen (or microbe)-associated molecular patterns (pamps/mamps) by pattern recognition receptors (prrs) is a key component of plant innate immunity. the arabidopsis prr ef-tu receptor (efr) recognizes the bacterial pamp elongation factor tu (ef-tu) and its derived peptide elf18. previous work revealed that transgenic expression of atefr in solanaceae confers elf18 responsiveness and broad-spectrum bacterial disease resistance. in this study, we developed a set of bioassays to stu ... | 2015 | 25760815 |
| two linked pairs of arabidopsis tnl resistance genes independently confer recognition of bacterial effector avrrps4. | plant immunity requires recognition of pathogen effectors by intracellular nb-lrr immune receptors encoded by resistance (r) genes. most r proteins recognize a specific effector, but some function in pairs that recognize multiple effectors. arabidopsis thaliana tir-nb-lrr proteins rrs1-r and rps4 together recognize two bacterial effectors, avrrps4 from pseudomonas syringae and popp2 from ralstonia solanacearum. however, avrrps4, but not popp2, is recognized in rrs1/rps4 mutants. we reveal an r g ... | 2015 | 25744164 |
| synthesis and antibacterial activities of yanglingmycin analogues. | the synthesis of yanglingmycin and its enantiomer, along with eighteen yanglingmycin analogues is reported. the structures were confirmed mainly by analyses of nmr spectral data. antibacterial activity assays showed that yanglingmycin and some of its analogues exhibited significant antibacterial activities against two important agricultural pathogenic bacteria, ralstonia solanacearum and pseudomonas syringae pv. actinidiae, with minimum inhibitory concentration (mic) values ranging from 3.91 to ... | 2015 | 25743192 |
| identification of plant defence regulators through transcriptional profiling of arabidopsis thaliana cdd1 mutant. | a sustainable balance between defence and growth is essential for optimal fitness under pathogen stress. plants activate immune response at the cost of normal metabolic requirements. thus, plants that constitutively activate defence are deprived of growth. arabidopsis thaliana mutant constitutive defence without defect in growth and development1 (cdd1) is an exception. the cdd1 mutant is constitutive for salicylic acid accumulation, signalling, and defence against biotrophic and hemibiotrophic p ... | 2015 | 25740148 |
| expression and functional roles of the pepper pathogen-induced bzip transcription factor cabzip2 in enhanced disease resistance to bacterial pathogen infection. | a pepper bzip transcription factor gene, cabzip2, was isolated from pepper leaves infected with a virulent strain of xanthomonas campestris pv. vesicatoria. transient expression analysis of the cabzip2-gfp fusion protein in nicotiana benthamiana revealed that the cabzip2 protein is localized in the cytoplasm as well as the nucleus. the acidic domain in the n-terminal region of cabzip2 that is fused to the gal4 dna-binding domain is required to activate the transcription of reporter genes in yeas ... | 2015 | 25738319 |
| a lectin s-domain receptor kinase mediates lipopolysaccharide sensing in arabidopsis thaliana. | the sensing of microbe-associated molecular patterns (mamps) triggers innate immunity in animals and plants. lipopolysaccharide (lps) from gram-negative bacteria is a potent mamp for mammals, with the lipid a moiety activating proinflammatory responses via toll-like receptor 4 (tlr4). here we found that the plant arabidopsis thaliana specifically sensed lps of pseudomonas and xanthomonas. we isolated lps-insensitive mutants defective in the bulb-type lectin s-domain-1 receptor-like kinase lore ( ... | 2015 | 25729922 |
| the plant-specific rab5 gtpase ara6 is required for starch and sugar homeostasis in arabidopsis thaliana. | endosomal trafficking plays integral roles in various eukaryotic cell activities. in animal cells, a member of the rab gtpase family, rab5, is a key regulator of various endosomal functions. in addition to orthologs of animal rab5, plants harbor the plant-specific rab5 group, the ara6 group, which is conserved in land plant lineages. in arabidopsis thaliana, ara6 and conventional rab5 act in distinct endosomal trafficking pathways; ara6 mediates trafficking from endosomes to the plasma membrane, ... | 2015 | 25713173 |
| the receptor-like cytoplasmic kinase pcrk1 contributes to pattern-triggered immunity against pseudomonas syringae in arabidopsis thaliana. | in this paper we describe pattern-triggered immunity (pti) compromised receptor-like cytoplasmic kinase 1 (pcrk1) of arabidopsis thaliana, an rlck that is important for defense against the pathogen pseudomonas syringae pv. maculicola es4326 (pma es4326). we examined defense responses such as bacterial growth, production of reactive oxygen species (ros) and callose deposition in pcrk1 mutant plants to determine the role of pcrk1 during pathogen infection. expression of pcrk1 was induced following ... | 2015 | 25711411 |
| the npr1 homolog ghnpr1 plays an important role in the defense response of gladiolus hybridus. | ghnpr1 shares similar functions as arabidopsis npr1 . silencing of ghnpr1 in gladiolus results in an enhanced susceptibility to curvularia gladioli. we propose that ghnpr1 plays important roles in plant immunity. gladiolus plants and corms are susceptible to various types of pathogens including fungi, bacteria and viruses. understanding the innate defense mechanism in gladiolus is a prerequisite for the development of new protection strategies. the non-expressor of pathogenesis-related gene 1 (n ... | 2015 | 25708873 |
| crystal structure of the effector protein hopa1 from pseudomonas syringae. | plants have evolved to protect themselves against pathogen attack; in these competitions, many gram-negative bacteria translocate pathogen-originated proteins known as effectors directly into plant cells to interfere with cellular processes. effector-triggered immunity (eti) is a plant defense mechanism in which plant resistance proteins recognize the presence of effectors and initiate immune responses. enhanced disease susceptibility 1 (eds1) in arabidopsis thaliana serves as a central node pro ... | 2015 | 25681297 |
| environmental stresses modulate abundance and timing of alternatively spliced circadian transcripts in arabidopsis. | environmental stresses profoundly altered accumulation of nonsense mrnas including intron-retaining (ir) transcripts in arabidopsis. temporal patterns of stress-induced ir mrnas were dissected using both oscillating and non-oscillating transcripts. broad-range thermal cycles triggered a sharp increase in the long ir cca1 isoforms and altered their phasing to different times of day. both abiotic and biotic stresses such as drought or pseudomonas syringae infection induced a similar increase. ther ... | 2015 | 25680774 |
| the stringent response mediated by (p)ppgpp is required for virulence of pseudomonas syringae pv. tomato and its survival on tomato. | the hypersensitive response and pathogenicity (hrp) type iii secretion system (t3ss) is a key pathogenicity factor in pseudomonas syringae pv. tomato dc3000 (dc3000). in this study, the role of the second messenger (p)ppgpp on virulence and survival of dc3000 was investigated. results have demonstrated that (p)ppgpp-deficient mutant (ppgpp(0)) of dc3000 exhibited lower levels of expression of the t3ss and genes of other virulence traits, such as coronatine toxin. the ppgpp(0) mutant of dc3000 wa ... | 2015 | 25675257 |
| a high-throughput screen for ligand binding reveals the specificities of three amino acid chemoreceptors from pseudomonas syringae pv. actinidiae. | chemoreceptors play a central role in chemotaxis, allowing bacteria to detect chemical gradients and bias their swimming behavior in order to navigate toward favorable environments. the genome of the kiwifruit pathogen, pseudomonas syringae pv. actinidiae (psa) strain nz-v13 encodes 43 predicted chemoreceptors, none of which has been characterized. we developed a high-throughput fluorescence-based thermal shift assay for identifying the signal molecules that are recognized by a given chemorecept ... | 2015 | 25656450 |
| dissection of two complex clusters of resistance genes in lettuce (lactuca sativa). | of the over 50 phenotypic resistance genes mapped in lettuce, 25 colocalize to three major resistance clusters (mrc) on chromosomes 1, 2, and 4. similarly, the majority of candidate resistance genes encoding nucleotide binding-leucine rich repeat (nlr) proteins genetically colocalize with phenotypic resistance loci. mrc1 and mrc4 span over 66 and 63 mb containing 84 and 21 nlr-encoding genes, respectively, as well as 765 and 627 genes that are not related to nlr genes. forward and reverse geneti ... | 2015 | 25650829 |
| levansucrases of a pseudomonas syringae pathovar as catalysts for the synthesis of potentially prebiotic oligo- and polysaccharides. | gut microbiota influences more physiological and developmental processes of humans and animals than earlier expected. therefore, the possibility to shape the composition and activity of this bacterial population by prebiotics becomes especially important. inulin, a β-2,1 linked fructan polymer, from plants and fructooligosaccharides (fos) derived from it are recognized and already widely used as prebiotics while β-2,6 linked fructans have received much less attention from scientific community. i ... | 2015 | 25644638 |
| biochemical characterization of uronate dehydrogenases from three pseudomonads, chromohalobacter salixigens, and polaromonas naphthalenivorans. | enzyme catalysts will be vital in the development of synthetic biology approaches for converting pectinic monosaccharides from citrus and beet processing waste streams to value-added materials. we describe here the biophysical and mechanistic characterization of uronate dehydrogenases from a wide variety of bacterial sources that convert galacturonic acid, the predominate building block of pectin from these plant sources, and glucuronic acid to their corresponding dicarboxylic acids galactarate ... | 2015 | 25640726 |
| identification of qtls controlling resistance to pseudomonas syringae pv. tomato race 1 strains from the wild tomato, solanum habrochaites la1777. | screening of wild tomato accessions revealed a source of resistance to pseudomonas syringe pv. tomato race 1 from solanum habrochaites and facilitated mapping of qtls controlling disease resistance. pseudomonas syringae pv. tomato (pst) causes bacterial speck of tomato, which is one of the most persistent bacterial diseases in tomato worldwide. existing pst populations have overcome genetic resistance mediated by the tomato genes pto and prf. the objective of this study was to identify sources o ... | 2015 | 25634105 |
| pseudomonas syringae effector avrpphb suppresses avrb-induced activation of rpm1 but not avrrpm1-induced activation. | the pseudomonas syringae effector avrb triggers a hypersensitive resistance response in arabidopsis and soybean plants expressing the disease resistance (r) proteins rpm1 and rpg1b, respectively. in arabidopsis, avrb induces rpm1-interacting protein kinase (ripk) to phosphorylate a disease regulator known as rin4, which subsequently activates rpm1-mediated defenses. here, we show that avrpphb can suppress activation of rpm1 by avrb and this suppression is correlated with the cleavage of ripk by ... | 2015 | 25625821 |
| the arabidopsis ceramidase atacer functions in disease resistance and salt tolerance. | ceramidases hydrolyze ceramide into sphingosine and fatty acids. in mammals, ceramidases function as key regulators of sphingolipid homeostasis, but little is known about their roles in plants. here we characterize the arabidopsis ceramidase atacer, a homolog of human alkaline ceramidases. the acer-1 t-dna insertion mutant has pleiotropic phenotypes, including reduction of leaf size, dwarfing and an irregular wax layer, compared with wild-type plants. quantitative sphingolipid profiling showed t ... | 2015 | 25619405 |
| chloroplasts play a central role in plant defence and are targeted by pathogen effectors. | microbe associated molecular pattern (mamp) receptors in plants recognize mamps and activate basal defences; however a complete understanding of the molecular and physiological mechanisms conferring immunity remains elusive. pathogens suppress active defence in plants through the combined action of effector proteins. here we show that the chloroplast is a key component of early immune responses. mamp perception triggers the rapid, large-scale suppression of nuclear encoded chloroplast-targeted g ... | 2015 | 27250009 |