| identification of novel type iii effectors using latent dirichlet allocation. | among the six secretion systems identified in gram-negative bacteria, the type iii secretion system (t3ss) plays important roles in the disease development of pathogens. t3ss has attracted a great deal of research interests. however, the secretion mechanism has not been fully understood yet. especially, the identification of effectors (secreted proteins) is an important and challenging task. this paper adopts machine learning methods to identify type iii secreted effectors (t3ses). we extract fe ... | 2012 | 22997537 |
| mpk11-a fourth elicitor-responsive mitogen-activated protein kinase in arabidopsis thaliana. | recognition of pathogen attack or elicitation with pathogen-associated molecular patterns (pamps) leads to defense signaling that includes activation of the three mitogen-activated protein kinases (mpks), mpk3, mpk4 and mpk6 in arabidopsis. recently, we demonstrated the activation of a fourth mpk, mpk11, after treatment with flg22, a 22 amino acid pamp derived from bacterial flagellin. here, we extended the study by examining elicitation with two other pamps, elf18 (derived from bacterial elonga ... | 2012 | 22899057 |
| sgt1b is required for hopz3-mediated suppression of the epiphytic growth of pseudomonas syringae on n. benthamiana. | type iii secreted effectors shape the potential of bacterial pathogens to cause disease on plants. some effectors affect pathogen growth only in specific niches. for example, hopz3 causes reduced epiphytic growth of pseudomonas syringae strain b728a on nicotiana benthamiana. this raises the question of whether genes important for effector-triggered disease resistance are needed for responses to effectors whose major effect is in the epiphytic niche. we report that sgt1b, a protein known to be im ... | 2012 | 22899059 |
| cml9, a multifunctional arabidopsis thaliana calmodulin-like protein involved in stress responses and plant growth? | plants have evolved complex signaling networks to respond to their fluctuating environment and adapt their growth and development. calcium-dependent signaling pathways play key role in the onset of these adaptive responses. in plant cells, the intracellular calcium transients are triggered by numerous stimuli and it is supposed that the large repertory of calcium sensors present in higher plants could contribute to integrate these signals in physiological responses. here, we present data on cml9 ... | 2012 | 22899061 |
| plant erd2s self-interact and interact with gtpase-activating proteins and adp-ribosylation factor 1. | erd2s (er luminal protein receptors)-mediated retrograde transport is one of the most substantial processes to maintain the endoplasmic reticulum (er) homeostasis. it is completed by the recognition of the escaped er luminal proteins, the gathering into cop i vesicle, and the fusion and releasing into the er. erd2s can recognize hdel/kdel motifs at the c-terminal of the escaped er luminal proteins at the golgi to initiate the retrograde transport. however, these mechanisms remain largely unknown ... | 2012 | 22899072 |
| disease resistance to pectobacterium carotovorum is negatively modulated by the arabidopsis lectin receptor kinase lecrk-v.5. | plant stomata function in disease resistance by restricting bacteria entry inside leaves. during plant-bacteria interactions, stomatal closure is initiated by the recognition of microbe-associated molecular patterns (mamps). recently, we have shown that the lectin receptor kinase v.5 (lecrk-v.5) negatively regulates bacterium- and mamp-induced stomatal closure upstream of reactive oxygen species (ros) production mediated by abscisic acid signaling. closed stomata in lecrk-v.5 mutants are correla ... | 2012 | 22899085 |
| gene discovery using mutagen-induced polymorphisms and deep sequencing: application to plant disease resistance. | next-generation sequencing technologies are accelerating gene discovery by combining multiple steps of mapping and cloning used in the traditional map-based approach into one step using dna sequence polymorphisms existing between two different accessions/strains/backgrounds of the same species. the existing next-generation sequencing method, like the traditional one, requires the use of a segregating population from a cross of a mutant organism in one accession with a wild-type (wt) organism in ... | 2012 | 22714407 |
| hcp2, a secreted protein of the phytopathogen pseudomonas syringae pv. tomato dc3000, is required for fitness for competition against bacteria and yeasts. | when analyzing the secretome of the plant pathogen pseudomonas syringae pv. tomato dc3000, we identified hemolysin-coregulated protein (hcp) as one of the secreted proteins. hcp is assumed to be an extracellular component of the type vi secretion system (t6ss). two copies of hcp genes are present in the p. syringae pv. tomato dc3000 genome, hcp1 (pspto_2539) and hcp2 (pspto_5435). we studied the expression patterns of the hcp genes and tested the fitness of hcp knockout mutants in host plant col ... | 2012 | 22753062 |
| contribution of surfactin and swra to flagellin expression, swimming, and surface motility in bacillus subtilis. | multicellular communities produced by bacillus subtilis can adopt sliding or swarming to translocate over surfaces. while sliding is a flagellum-independent motility produced by the expansive forces in a growing colony, swarming requires flagellar functionality and is characterized by the appearance of hyperflagellated swarm cells that associate in bundles or rafts during movement. previous work has shown that swarming by undomesticated b. subtilis strains requires swra, a gene that upregulates ... | 2012 | 22773650 |
| 14-3-3-regulated ca(2+)-dependent protein kinase cpk3 is required for sphingolipid-induced cell death in arabidopsis. | in eukaryotic cells, sphingoid long chain bases (lcbs) such as sphingosine or phytosphingosine (phs) behave as second messengers involved in various processes including programmed cell death (pcd). in plants, induction of pcd by lcbs has now been described, but the signalling pathway is still enigmatic. using arabidopsis, we identify new key steps in this pathway. we demonstrate that phs induces activation of the calcium-dependent kinase cpk3, which phosphorylates its binding partners, the 14-3- ... | 2012 | 22935611 |
| 14-3-3-regulated ca(2+)-dependent protein kinase cpk3 is required for sphingolipid-induced cell death in arabidopsis. | in eukaryotic cells, sphingoid long chain bases (lcbs) such as sphingosine or phytosphingosine (phs) behave as second messengers involved in various processes including programmed cell death (pcd). in plants, induction of pcd by lcbs has now been described, but the signalling pathway is still enigmatic. using arabidopsis, we identify new key steps in this pathway. we demonstrate that phs induces activation of the calcium-dependent kinase cpk3, which phosphorylates its binding partners, the 14-3- ... | 2012 | 22935611 |
| polyphenol oxidases in physcomitrella: functional ppo1 knockout modulates cytokinin-dependent development in the moss physcomitrella patens. | polyphenol oxidases (ppos) are copper-binding enzymes of the plant secondary metabolism that oxidize polyphenols to quinones. although ppos are nearly ubiquitous in seed plants, knowledge on their evolution and function in other plant groups is missing. this study reports on the ppo gene family in the moss physcomitrella patens (hedw.) b.s.g. asan example for an early divergent plant. the p. patens ppo multigene family comprises 13 paralogues. phylogenetic analyses suggest that plant ppos evolve ... | 2012 | 22865913 |
| dissection of two soybean qtl conferring partial resistance to phytophthora sojae through sequence and gene expression analysis. | phytophthora sojae is the primary pathogen of soybeans that are grown on poorly drained soils. race-specific resistance to p. sojae in soybean is gene-for-gene, although in many areas of the us and worldwide there are populations that have adapted to the most commonly deployed resistance to p. sojae ( rps) genes. hence, this system has received increased attention towards identifying mechanisms and molecular markers associated with partial resistance to this pathogen. several quantitative trait ... | 2012 | 22925529 |
| nitric oxide-mediated maintenance of redox homeostasis contributes to npr1-dependent plant innate immunity triggered by lipopolysaccharides. | the perception of lipopolysaccharides (lps) by plant cells can lead to nitric oxide (no) production and defense gene induction. however, the signaling cascades underlying these cellular responses have not yet been resolved. this work investigated the biosynthetic origin of no and the role of nonexpressor of pathogenesis-related genes1 (npr1) to gain insight into the mechanism involved in lps-induced resistance of arabidopsis (arabidopsis thaliana). analysis of inhibitors and mutants showed that ... | 2012 | 22926319 |
| the shoot apical meristem regulatory peptide clv3 does not activate innate immunity. | the arabidopsis thaliana leucine-rich repeat receptor kinase flagellin sensing2 (fls2) is required for the recognition of bacterial flagellin in innate immunity. recently, fls2 was proposed to act as a multispecific receptor recognizing unrelated exogenous and endogenous peptide ligands, including clavata3 (clv3), a key regulator of shoot meristem stem cell production. here, we report experimental evidence demonstrating that fls2 does not recognize clv3 and that the shoot apical meristem is immu ... | 2012 | 22923673 |
| complexity in differential peptide-receptor signaling: response to segonzac et al. and mueller et al. commentaries. | | 2012 | 22923676 |
| fls2-mediated responses to ax21-derived peptides: response to the mueller et al. commentary. | | 2012 | 22923675 |
| receptor-like kinase complexes in plant innate immunity. | receptor-like kinases (rlks) are surface localized, transmembrane receptors comprising a large family of well-studied kinases. rlks signal through their transmembrane and juxtamembrane domains with the aid of various interacting partners and downstream components. the n-terminal extracellular domain defines ligand specificity, and rlk families are sub-classed according to this domain. the most studied of these subfamilies include those with (1) leucine-rich repeat (lrr) domains, (2) lysm domains ... | 2012 | 22936944 |
| evolutionary genomics of host-use in bifurcating demes of rna virus phi-6. | viruses are exceedingly diverse in their evolved strategies to manipulate hosts for viral replication. however, despite these differences, most virus populations will occasionally experience two commonly-encountered challenges: growth in variable host environments, and growth under fluctuating population sizes. we used the segmented rna bacteriophage ϕ6 as a model for studying the evolutionary genomics of virus adaptation in the face of host switches and parametrically varying population sizes. ... | 2012 | 22913547 |
| minutissamides e-l, antiproliferative cyclic lipodecapeptides from the cultured freshwater cyanobacterium cf. anabaena sp. | the extract of uic 10035, a strain obtained from a sample collected near the town of homestead, south florida, showed antiproliferative activity against mda-mb-435 cells. bioassay-guided fractionation led to the isolation of a series of cyclic lipodecapeptides, named minutissamides e-l (1-8). the planar structures were determined by analysis of hresims, tandem ms, and 1d and 2d nmr data, and the stereoconfigurations were assigned by lc-ms analysis of the marfey's derivatives after acid hydrolysi ... | 2012 | 22980217 |
| dissecting phaseolus vulgaris innate immune system against colletotrichum lindemuthianum infection. | the genus colletotrichum is one of the most economically important plant pathogens, causing anthracnose on a wide range of crops including common beans (phaseolus vulgaris l.). crop yield can be dramatically decreased depending on the plant cultivar used and the environmental conditions. this study aimed to identify potential genetic components of the bean immune system to provide environmentally friendly control measures against this fungus. | 2012 | 22912818 |
| two novel ring-type ubiquitin ligases, rglg3 and rglg4, are essential for jasmonate-mediated responses in arabidopsis. | jasmonates (jas) regulate various stress responses and development processes in plants, and the ja pathway is tightly controlled. in this study, we report the functional characterization of two novel ring-type ubiquitin ligases, ring domain ligase3 (rglg3) and rglg4, in modulating ja signaling. both rglg3 and rglg4 possessed ubiquitin ligase activities and were widely distributed in arabidopsis (arabidopsis thaliana) tissues. altered expression of rglg3 and rglg4 affected methyl ja-inhibited roo ... | 2012 | 22898498 |
| attenuation of quorum sensing in the pathogen acinetobacter baumannii using non-native n-acyl homoserine lactones. | many bacterial pathogens use quorum sensing (qs) to control virulence. as a result, the development of methods to intercept qs has attracted significant interest as a potential anti-infective therapy. acinetobacter baumannii has emerged as a pan-drug-resistant pathogen and displays a remarkable ability to persist in hospital settings despite desiccation and antimicrobial treatment. recent studies have shown that a. baumannii qs mutants have limited motility and fail to form mature biofilms; thes ... | 2012 | 22853441 |
| the arabidopsis della rga-like3 is a direct target of myc2 and modulates jasmonate signaling responses. | gibberellins (gas) are plant hormones involved in the regulation of plant growth in response to endogenous and environmental signals. ga promotes growth by stimulating the degradation of nuclear growth-repressing della proteins. in arabidopsis thaliana, dellas consist of a small family of five proteins that display distinct but also overlapping functions in repressing ga responses. this study reveals that della rga-like3 (rgl3) protein is essential to fully enhance the jasmonate (ja)-mediated re ... | 2012 | 22892320 |
| hspro controls early nicotiana attenuata seedling growth during interaction with the fungus piriformospora indica. | in a previous study aimed at identifying regulators of nicotiana attenuata responses against chewing insects, a 26-nucleotide tag matching the hspro (ortholog of sugar beet hs1(pro)(-)(1)) gene was found to be strongly induced after simulated herbivory (gilardoni et al., 2010). here we characterized the function of hspro during biotic interactions in transgenic n. attenuata plants silenced in its expression (ir-hspro). in wild-type plants, hspro expression was not only induced during simulated h ... | 2012 | 22892352 |
| discovery of stress responsive dna regulatory motifs in arabidopsis. | the discovery of dna regulatory motifs in the sequenced genomes using computational methods remains challenging. here, we present motifindexer--a comprehensive strategy for de novo identification of dna regulatory motifs at a genome level. using word-counting methods, we indexed the existence of every 8-mer oligo composed of bases a, c, g, t, r, y, s, w, m, k, n or 12-mer oligo composed of a, c, g, t, n, in the promoters of all predicted genes of arabidopsis thaliana genome and of selected stres ... | 2012 | 22912824 |
| ghwrky15, a member of the wrky transcription factor family identified from cotton (gossypium hirsutum l.), is involved in disease resistance and plant development. | as a large family of regulatory proteins, wrky transcription factors play essential roles in the processes of adaptation to diverse environmental stresses and plant growth and development. although several studies have investigated the role of wrky transcription factors during these processes, the mechanisms underlying the function of wrky members need to be further explored, and research focusing on the wrky family in cotton crops is extremely limited. | 2012 | 22883108 |
| host protein bsl1 associates with phytophthora infestans rxlr effector avr2 and the solanum demissum immune receptor r2 to mediate disease resistance. | plant pathogens secrete effector proteins to modulate plant immunity and promote host colonization. plant nucleotide binding leucine-rich repeat (nb-lrr) immunoreceptors recognize specific pathogen effectors directly or indirectly. little is known about how nb-lrr proteins recognize effectors of filamentous plant pathogens, such as phytophthora infestans. avr2 belongs to a family of 13 sequence-divergent p. infestans rxlr effectors that are differentially recognized by members of the r2 nb-lrr f ... | 2012 | 22885736 |
| atpase site architecture is required for self-assembly and remodeling activity of a hexameric aaa+ transcriptional activator. | aaa+ proteins (atpases associated with various cellular activities) are oligomeric atpases that use atp hydrolysis to remodel their substrates. by similarity with gtpases, a dynamic organization of the nucleotide-binding pockets between atpase protomers is proposed to regulate functionality. using the transcription activator pspf as an aaa+ model, we investigated contributions of conserved residues for roles in atp hydrolysis and intersubunit communication. we determined the r-finger residue and ... | 2012 | 22789710 |
| genome-wide mapping of nbs-lrr genes and their association with disease resistance in soybean. | r genes are a key component of genetic interactions between plants and biotrophic bacteria and are known to regulate resistance against bacterial invasion. the most common r proteins contain a nucleotide-binding site and a leucine-rich repeat (nbs-lrr) domain. some nbs-lrr genes in the soybean genome have also been reported to function in disease resistance. in this study, the number of nbs-lrr genes was found to correlate with the number of disease resistance quantitative trait loci (qtl) that ... | 2012 | 22877146 |
| lysin motif-containing proteins lyp4 and lyp6 play dual roles in peptidoglycan and chitin perception in rice innate immunity. | plant innate immunity relies on successful detection of microbe-associated molecular patterns (mamps) of invading microbes via pattern recognition receptors (prrs) at the plant cell surface. here, we report two homologous rice (oryza sativa) lysin motif-containing proteins, lyp4 and lyp6, as dual functional prrs sensing bacterial peptidoglycan (pgn) and fungal chitin. live cell imaging and microsomal fractionation consistently revealed the plasma membrane localization of these proteins in rice c ... | 2012 | 22872757 |
| characterization of the nrt2.6 gene in arabidopsis thaliana: a link with plant response to biotic and abiotic stress. | the high affinity nitrate transport system in arabidopsis thaliana involves one gene and potentially seven genes from the nrt1 and nrt2 family, respectively. among them, nrt2.1, nrt2.2, nrt2.4 and nrt2.7 proteins have been shown to transport nitrate and are localized on the plasmalemma or the tonoplast membranes. nrt2.1, nrt2.2 and nrt2.4 play a role in nitrate uptake from soil solution by root cells while nrt2.7 is responsible for nitrate loading in the seed vacuole. we have undertaken the func ... | 2012 | 22880003 |
| transcriptome profiling of resistant and susceptible cavendish banana roots following inoculation with fusarium oxysporum f. sp. cubense tropical race 4. | fusarium wilt, caused by the fungal pathogen fusarium oxysporum f. sp. cubense tropical race 4 (foc tr4), is considered the most lethal disease of cavendish bananas in the world. the disease can be managed in the field by planting resistant cavendish plants generated by somaclonal variation. however, little information is available on the genetic basis of plant resistance to foc tr4. to a better understand the defense response of resistant banana plants to the fusarium wilt pathogen, the transcr ... | 2012 | 22863187 |
| solution nmr and x-ray crystal structures of pseudomonas syringae pspto_3016 from protein domain family pf04237 (duf419) adopt a "double wing" dna binding motif. | the protein pspto_3016 is a 117-residue member of the protein domain family pf04237 (duf419), which is to date a functionally uncharacterized family of proteins. in this report, we describe the structure of pspto_3016 from pseudomonas syringae solved by both solution nmr and x-ray crystallography at 2.5 å resolution. in both cases, the structure of pspto_3016 adopts a "double wing" α/β sandwich fold similar to that of protein yjbr from escherichia coli and to the c-terminal dna binding domain of ... | 2012 | 22865330 |
| ft-icr/ms and gc-ei/ms metabolomics networking unravels global potato sprout's responses to rhizoctonia solani infection. | the complexity of plant-pathogen interactions makes their dissection a challenging task for metabolomics studies. here we are reporting on an integrated metabolomics networking approach combining gas chromatography/mass spectrometry (gc/ms) with fourier transform ion cyclotron resonance/mass spectrometry (ft-icr/ms) and bioinformatics analyses for the study of interactions in the potato sprout-rhizoctonia solani pathosystem and the fluctuations in the global metabolome of sprouts. the developed ... | 2012 | 22880040 |
| protein phosphorylation in plant immunity: insights into the regulation of pattern recognition receptor-mediated signaling. | plants are continuously challenged by pathogens including viruses, bacteria, and fungi. the plant immune system recognizes invading pathogens and responds by activating an immune response. these responses occur rapidly and often involve post-translational modifications (ptms) within the proteome. protein phosphorylation is a common and intensively studied form of these ptms and regulates many plant processes including plant growth, development, and immunity. most well-characterized pattern recog ... | 2012 | 22876255 |
| methylation--an uncommon modification of glycans. | a methyl (me) group on a sugar residue is a rarely reported event. until now, this type of modification has been found in the animal kingdom only in worms and molluscs, whereas it is more frequently present in some species of bacteria, fungi, algae and plants, but not in mammals. the monosaccharides involved as well as the positions of the me groups on the sugar vary with species. methylation appears to play a role in some recognition events, but details are still unknown. this review summarises ... | 2012 | 22944672 |
| the function of calreticulin in plant immunity: new discoveries for an old protein. | since its initial discovery as a high affinity ca ( 2+) -binding protein in the sarcoplasmic reticulum and endoplasmic reticulum (er), calreticulin (crt) has been documented to be a multifunctional protein in both animal and plant cells. this protein is well recognized as a ca ( 2+) -binding molecular chaperone that facilitates the folding of newly synthesized glycoproteins and regulates the ca ( 2+) homeostasis in the er lumen. however, functional relevance associated with its localization in o ... | 2012 | 22827946 |
| modulation of ros production and hormone levels by ahk5 during abiotic and biotic stress signaling. | histidine kinases have been shown to mediate responses to endogenous and exogenous stimuli in organisms such as yeast, bacteria and plants. in the model plant arabidopsis, histidine kinases have been shown to function in hormone signaling, and abiotic and biotic stress responses. more recently, the least characterized of the arabidopsis histidine kinases, ahk5, was demonstrated to function in resistance toward the virulent bacterium pseudomonas syringae pv tomato dc3000 (pstdc3000) and the necro ... | 2012 | 22827948 |
| the prolific atl family of ring-h2 ubiquitin ligases. | an abundant class of e3 ubiquitin ligases encodes the ring-finger domain. the ring finger binds to the e2 ubiquitin-conjugating enzyme and brings together both the e2 and substrate. it is predicted that 477 ring finger e3 ligases exist in arabidopsis thaliana. a particular family among them, named arabidopsis tóxicos en levadura (atl), consists of 91 members that contain the ring-h2 variation and a hydrophobic domain located at the n-terminal end. transmembrane e3 ligases are important in severa ... | 2012 | 22827943 |
| expanded roles for multicargo and class 1b effector chaperones in type iii secretion. | bacterial type iii secretion systems (t3ss) are complex protein assemblies that mediate the secretion of protein substrates outside the cell. type iii secretion chaperones (t3sc) are always found associated with t3ss, and they serve in multiple roles to ensure that protein substrates are efficiently targeted for secretion. bacterial pathogens with t3ss express t3sc proteins that bind effectors, a process important for effector protein delivery into eukaryotic cells during infection. in this mini ... | 2012 | 22636784 |
| involvement of two-component system cbo0366/cbo0365 in the cold shock response and growth of group i (proteolytic) clostridium botulinum atcc 3502 at low temperatures. | the role of the two-component system (tcs) cbo0366/cbo0365 in the cold shock response and growth of the mesophilic clostridium botulinum atcc 3502 at 15°c was demonstrated by induced expression of the tcs genes upon cold shock and impaired growth of the tcs mutants at 15°c. | 2012 | 22660717 |
| a high-throughput forward genetic screen identifies genes required for virulence of pseudomonas syringae pv. maculicola es4326 on arabidopsis. | successful pathogenesis requires a number of coordinated processes whose genetic bases remain to be fully characterized. we utilized a high-throughput, liquid media-based assay to screen transposon disruptants of the phytopathogen pseudomonas syringae pv. maculicola es4326 to identify genes required for virulence on arabidopsis. many genes identified through this screen were involved in processes such as type iii secretion, periplasmic glucan biosynthesis, flagellar motility, and amino acid bios ... | 2012 | 22870224 |
| the novel kasugamycin 2'-n-acetyltransferase gene aac(2')-iia, carried by the incp island, confers kasugamycin resistance to rice-pathogenic bacteria. | kasugamycin (ksm), a unique aminoglycoside antibiotic, has been used in agriculture for many years to control not only rice blast caused by the fungus magnaporthe grisea but also rice bacterial grain and seedling rot or rice bacterial brown stripe caused by burkholderia glumae or acidovorax avenae subsp. avenae, respectively. since both bacterial pathogens are seed-borne and cause serious injury to rice seedlings, the emergence of ksm-resistant b. glumae and a. avenae isolates highlights the urg ... | 2012 | 22660700 |
| ketoglutarate transport protein kgtp is secreted through the type iii secretion system and contributes to virulence in xanthomonas oryzae pv. oryzae. | the phytopathogenic prokaryote xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight (bb) of rice and utilizes a type iii secretion system (t3ss) to deliver t3ss effectors into rice cells. in this report, we show that the ketoglutarate transport protein (kgtp) is secreted in an hpab-independent manner through the t3ss of x. oryzae pv. oryzae pxo99(a) and localizes to the host cell membrane for α-ketoglutaric acid export. kgtp contained an imperfect pip box (plant-inducible p ... | 2012 | 22685129 |
| influence of the plant defense response to escherichia coli o157:h7 cell surface structures on survival of that enteric pathogen on plant surfaces. | consumption of fresh and fresh-cut fruits and vegetables contaminated with escherichia coli o157:h7 has resulted in hundreds of cases of illness and, in some instances, death. in this study, the influence of cell surface structures of e. coli o157:h7, such as flagella, curli fimbriae, lipopolysaccharides, or exopolysaccharides, on plant defense responses and on survival or colonization on the plant was investigated. the population of the e. coli o157:h7 atcc 43895 wild-type strain was significan ... | 2012 | 22706044 |
| phytohormone signaling pathway analysis method for comparing hormone responses in plant-pest interactions. | phytohormones mediate plant defense responses to pests and pathogens. in particular, the hormones jasmonic acid, ethylene, salicylic acid, and abscisic acid have been shown to dictate and fine-tune defense responses, and identification of the phytohormone components of a particular defense response is commonly used to characterize it. identification of phytohormone regulation is particularly important in transcriptome analyses. currently there is no computational tool to determine the relative a ... | 2012 | 22846705 |
| genetic and physical mapping of candidate genes for resistance to fusarium oxysporum f.sp. tracheiphilum race 3 in cowpea [vigna unguiculata (l.) walp]. | fusarium oxysporum f.sp. tracheiphilum (fot) is a soil-borne fungal pathogen that causes vascular wilt disease in cowpea. fot race 3 is one of the major pathogens affecting cowpea production in california. identification of fot race 3 resistance determinants will expedite delivery of improved cultivars by replacing time-consuming phenotypic screening with selection based on perfect markers, thereby generating successful cultivars in a shorter time period. resistance to fot race 3 was studied in ... | 2012 | 22860000 |
| genome-wide identification of pseudomonas aeruginosa virulence-related genes using a caenorhabditis elegans infection model. | pseudomonas aeruginosa strain pa14 is an opportunistic human pathogen capable of infecting a wide range of organisms including the nematode caenorhabditis elegans. we used a non-redundant transposon mutant library consisting of 5,850 clones corresponding to 75% of the total and approximately 80% of the non-essential pa14 orfs to carry out a genome-wide screen for attenuation of pa14 virulence in c. elegans. we defined a functionally diverse 180 mutant set (representing 170 unique genes) necessar ... | 2012 | 22911607 |
| dynamic differential methylation facilitates pathogen stress response in arabidopsis. | | 2012 | 22837399 |
| atp hydrolyzing salivary enzymes of caterpillars suppress plant defenses. | the oral secretions of herbivores are important recognition cues that can be used by plants to mediate induced defenses. in this study, a degradation of adenosine-5'-triphosphate (atp) in tomato leaves was detected after treatment with helicoverpa zea saliva. correspondingly, a high level of atpase activity in saliva was detected and three atp hydrolyzing enzymes: apyrase, atp synthase and atpase 13a1 were identified in salivary glands. to determine the functions of these proteins in mediating d ... | 2012 | 22848670 |
| map kinase cascades in arabidopsis innate immunity. | plant mitogen-activated protein kinase (mapk) cascades generally transduce extracellular stimuli into cellular responses. these stimuli include the perception of pathogen-associated molecular patterns (pamps) by host transmembrane pattern recognition receptors which trigger mapk-dependent innate immune responses. in the model arabidopsis, molecular genetic evidence implicates a number of mapk cascade components in pamp signaling, and in responses to immunity-related phytohormones such as ethylen ... | 2012 | 22837762 |
| plant innate immunity induced by flagellin suppresses the hypersensitive response in non-host plants elicited by pseudomonas syringae pv. averrhoi. | a new pathogen, pseudomonas syringae pv. averrhoi (pav), which causes bacterial spot disease on carambola was identified in taiwan in 1997. many strains of this pathovar have been isolated from different locations and several varieties of hosts. some of these strains, such as hl1, are nonmotile and elicit a strong hypersensitive response (hr) in nonhost tobacco leaves, while other strains, such as pa5, are motile and elicit a weak hr. based on the image from a transmission electron microscope, t ... | 2012 | 22911741 |
| a nac transcription factor and sni1 cooperatively suppress basal pathogen resistance in arabidopsis thaliana. | transcriptional repression of pathogen defense-related genes is essential for plant growth and development. several proteins are known to be involved in the transcriptional regulation of plant defense responses. however, mechanisms by which expression of defense-related genes are regulated by repressor proteins are poorly characterized. here, we describe the in planta function of cbnac, a calmodulin-regulated nac transcriptional repressor in arabidopsis. a t-dna insertional mutant (cbnac1) displ ... | 2012 | 22826500 |
| lipid profiling of the arabidopsis hypersensitive response reveals specific lipid peroxidation and fragmentation processes: biogenesis of pimelic and azelaic acid. | lipid peroxidation (lpo) is induced by a variety of abiotic and biotic stresses. although lpo is involved in diverse signaling processes, little is known about the oxidation mechanisms and major lipid targets. a systematic lipidomics analysis of lpo in the interaction of arabidopsis (arabidopsis thaliana) with pseudomonas syringae revealed that lpo is predominantly confined to plastid lipids comprising galactolipid and triacylglyceride species and precedes programmed cell death. singlet oxygen w ... | 2012 | 22822212 |
| the arabidopsis mediator subunit med25 differentially regulates jasmonate and abscisic acid signaling through interacting with the myc2 and abi5 transcription factors. | transcriptional regulation plays a central role in plant hormone signaling. at the core of transcriptional regulation is the mediator, an evolutionarily conserved, multisubunit complex that serves as a bridge between gene-specific transcription factors and the rna polymerase machinery to regulate transcription. here, we report the action mechanisms of the mediator25 (med25) subunit of the arabidopsis thaliana mediator in regulating jasmonate- and abscisic acid (aba)-triggered gene transcription. ... | 2012 | 22822206 |
| genes involved in the evolution of herbivory by a leaf-mining, drosophilid fly. | herbivorous insects are among the most successful radiations of life. however, we know little about the processes underpinning the evolution of herbivory. we examined the evolution of herbivory in the fly, scaptomyza flava, whose larvae are leaf miners on species of brassicaceae, including the widely studied reference plant, arabidopsis thaliana (arabidopsis). scaptomyza flava is phylogenetically nested within the paraphyletic genus drosophila, and the whole genome sequences available for 12 spe ... | 2012 | 22813779 |
| canopy light and plant health. | | 2012 | 22802612 |
| effector-triggered post-translational modifications and their role in suppression of plant immunity. | plant-pathogen interactions feature complex signaling exchanges between host and microbes that ultimately determine association outcomes. plants deploy pattern recognition receptors to perceive pathogen-associated molecular patterns, mount pattern-triggered immunity (pti), and fend off potential pathogens. in recent years an increasing number of defense-signaling components have been identified along with a mechanistic understanding of their regulation during immune responses. post-translational ... | 2012 | 22811685 |
| the lateral organ boundaries domain transcription factor lbd20 functions in fusarium wilt susceptibility and jasmonate signaling in arabidopsis. | the lateral organ boundaries (lob) domain (lbd) gene family encodes plant-specific transcriptional regulators functioning in organ development. in a screen of arabidopsis (arabidopsis thaliana) sequence-indexed transferred dna insertion mutants, we found disruption of the lob domain-containing protein20 (lbd20) gene led to increased resistance to the root-infecting vascular wilt pathogen fusarium oxysporum. in wild-type plants, lbd20 transcripts were barely detectable in leaves but abundant in r ... | 2012 | 22786889 |
| antisense rna that affects rhodopseudomonas palustris quorum-sensing signal receptor expression. | quorum sensing in the bacterium rhodopseudomonas palustris involves the rpai signal synthase, which produces p-coumaroyl-homoserine lactone (pc-hsl) and rpar, which is a pc-hsl-dependent transcriptional activator. there is also an antisense rpar transcript (asrpar) of unknown function. recent rnaseq studies have revealed that bacterial antisense rnas are abundant, but little is known about the function of these molecules. because asrpar expression is quorum sensing dependent, we sought to charac ... | 2012 | 22778415 |
| histological examination of horse chestnut infection by pseudomonas syringae pv. aesculi and non-destructive heat treatment to stop disease progression. | since its emergence in northwest europe as a pathogen that infects trunks and branches of aesculus spp. (the horse chestnuts) approximately one decade ago, pseudomonas syringae pv. aesculi has rapidly established itself as major threat to these trees. infected trees exhibit extensive necrosis of phloem and cambium, which can ultimately lead to dieback. the events after host entry leading to extensive necrosis are not well documented. in this work, the histopathology of this interaction is invest ... | 2012 | 22808044 |
| identification of three mapkkks forming a linear signaling pathway leading to programmed cell death in nicotiana benthamiana. | the mitogen-activated protein kinase (mapk) cascade is an evolutionarily ancient mechanism of signal transduction found in eukaryotic cells. in plants, mapk cascades are associated with responses to various abiotic and biotic stresses such as plant pathogens. mapk cascades function through sequential phosphorylation: mapk kinase kinases (mapkkks) phosphorylate mapk kinases (mapkks), and phosphorylated mapkks phosphorylate mapks. of these three types of kinase, the mapkkks exhibit the most diverg ... | 2012 | 22770370 |
| genes for plant autophagy: functions and interactions. | autophagy, or self-consuming of cytoplasmic constituents in a lytic compartment, plays a crucial role in nutrient recycling, development, cell homeostasis, and defense against pathogens and toxic products. autophagy in plant cells uses a conserved machinery of core autophagy-related (atg) proteins. recently, research on plant autophagy has been expanding and other components interacting with the core atg proteins are being revealed. in addition, growing evidence suggests that autophagy communica ... | 2012 | 22772908 |
| acyl-homoserine lactone-dependent eavesdropping promotes competition in a laboratory co-culture model. | many proteobacteria use acyl-homoserine lactone (ahl)-mediated quorum sensing to activate the production of antibiotics at high cell density. extracellular factors like antibiotics can be considered public goods shared by individuals within a group. quorum-sensing control of antibiotic production may be important for protecting a niche or competing for limited resources in mixed bacterial communities. to begin to investigate the role of quorum sensing in interspecies competition, we developed a ... | 2012 | 22763647 |
| variation in extragenic repetitive dna sequences in pseudomonas syringae and potential use of modified rep primers in the identification of closely related isolates. | in this study, pseudomonas syringe pathovars isolated from olive, tomato and bean were identified by species-specific pcr and their genetic diversity was assessed by repetitive extragenic palindromic (rep)-pcr. reverse universal primers for rep-pcr were designed by using the bases of a, t, g or c at the positions of 1, 4 and 11 to identify additional polymorphism in the banding patterns. binding of the primers to different annealing sites in the genome revealed additional fingerprint patterns in ... | 2012 | 23055805 |
| uv-b irradiation changes specifically the secondary metabolite profile in broccoli sprouts: induced signaling overlaps with defense response to biotic stressors. | only a few environmental factors have such a pronounced effect on plant growth and development as ultraviolet light (uv). concerns have arisen due to increased uv-b radiation reaching the earth's surface as a result of stratospheric ozone depletion. ecologically relevant low to moderate uv-b doses (0.3-1 kj m(-2) d(-1)) were applied to sprouts of the important vegetable crop brassica oleracea var. italica (broccoli), and eco-physiological responses such as accumulation of non-volatile secondary ... | 2012 | 22773681 |
| influence of atp-binding cassette transporters in root exudation of phytoalexins, signals, and in disease resistance. | the roots of plants secrete compounds as a way to exchange information with organisms living in the soil. here, we report the involvement of seven root-expressed atp-binding cassette (abc) transporters corresponding to both full and half-size molecules (atabcg36, atabcg37, atabcc5, atabcf1, atabcf3, atnap5, and atath10) in root exudation processes using arabidopsis thaliana. root exuded phytochemicals were analyzed by high-performance liquid chromatography-mass spectrometry (hplc-ms) and gas chr ... | 2012 | 22783269 |
| the crystal structure of the periplasmic domain of vibrio parahaemolyticus cpxa. | the cpx two-component system of gram-negative bacteria senses extracytoplasmic stresses using the histidine kinase cpxa, a membrane-bound sensor, and controls the transcription of the genes involved in stress response by the cytosolic response regulator cpxr, which is activated by the phosphorelay from cpxa. cpxp, a cpxa-associated protein, also plays an important role in the regulation of the cpx system by inhibiting the autophosphorylation of cpxa. although the stress signals and physiological ... | 2012 | 22760860 |
| the beginnings of crop phosphoproteomics: exploring early warning systems of stress. | this review examines why a knowledge of plant protein phosphorylation events is important in devising strategies to protect crops from both biotic and abiotic stresses, and why proteomics should be included when studying stress pathways. most of the achievements in elucidating phospho-signaling pathways in biotic and abiotic stress are reported from model systems: while these are discussed, this review attempts mainly to focus on work done with crops, with examples of achievements reported from ... | 2012 | 22783265 |
| compartment-specific antioxidative defense in arabidopsis against virulent and avirulent pseudomonas syringae. | the accumulation of reactive oxygen species (ros) during biotic stress is either part of a hypersensitive response of the plant or induced directly by the pathogen. antioxidants such as ascorbate and glutathione counteract the accumulation of ros and are part of the defense reaction. the aim of the present study was to investigate the compartment-specific importance of ascorbate and glutathione during a virulent and avirulent pseudomonas syringae infection in arabidopsis thaliana. peroxisomes we ... | 2012 | 22571419 |
| exploring optimization parameters to increase ssdna recombineering in lactococcus lactis and lactobacillus reuteri. | single-stranded dna (ssdna) recombineering is a technology which is used to make subtle changes in the chromosome of several bacterial genera. cells which express a single-stranded dna binding protein (rect or bet) are transformed with an oligonucleotide which is incorporated via an annealing and replication-dependent mechanism. by in silico analysis we identified ssdna binding protein homologs in the genus lactobacillus and lactococcus lactis. to assess whether we could further improve the reco ... | 2012 | 22750793 |
| draft genome sequence of pseudomonas syringae pathovar syringae strain ff5, causal agent of stem tip dieback disease on ornamental pear. | pseudomonas syringae ff5 causes stem tip dieback disease on ornamental pear (pyrus calleryana). its genome encodes a complete type iii secretion system (t3ss) and hopac1, hopm1, avre1, hopi1, hopaa1, hopj1, hopah2, hopah1, hopag1, and hopaz1. lacking detectable homologues of other t3ss effectors, it may encode novel, undiscovered effectors. | 2012 | 22740663 |
| novel miniature transposable elements in thermophilic synechococcus strains and their impact on an environmental population. | the genomes of the two closely related freshwater thermophilic cyanobacteria synechococcus sp. strain ja-3-3ab and synechococcus sp. strain ja-2-3b'a(2-13) each host several families of insertion sequences (issoc families) at various copy numbers, resulting in an overall high abundance of insertion sequences in the genomes. in addition to full-length copies, a large number of internal deletion variants have been identified. issoc2 has two variants (issoc2∂-1 and issoc2∂-2) that are observed to h ... | 2012 | 22563047 |
| lyk4, a lysin motif receptor-like kinase, is important for chitin signaling and plant innate immunity in arabidopsis. | chitin is commonly found in fungal cell walls and is one of the well-studied microbe/pathogen-associated molecular patterns. previous studies showed that lysin motif (lysm)-containing proteins are essential for plant recognition of chitin, leading to the activation of plant innate immunity. in arabidopsis (arabidopsis thaliana), the lyk1/cerk1 (for lysm-containing receptor-like kinase1/chitin elicitor receptor kinase1) was shown to be essential for chitin recognition, whereas in rice (oryza sati ... | 2012 | 22744984 |
| the ankyrin-repeat transmembrane protein bda1 functions downstream of the receptor-like protein snc2 to regulate plant immunity. | plants utilize a large number of immune receptors to recognize pathogens and activate defense responses. a small number of these receptors belong to the receptor-like protein family. previously, we showed that a gain-of-function mutation in the receptor-like protein snc2 (for suppressor of npr1, constitutive2) leads to constitutive activation of defense responses in snc2-1d mutant plants. to identify defense signaling components downstream of snc2, we carried out a suppressor screen in the snc2- ... | 2012 | 22740615 |
| identification of soybean micrornas involved in soybean cyst nematode infection by deep sequencing. | soybean cyst nematode (scn), heterodera glycines, is the most devastating pathogen of soybean worldwide. micrornas (mirnas) are a class of small, non-coding rnas that are known to play important role in plant stress response. however, there are few reports profiling the mirna expression patterns during pathogen stress. we sequenced four small rna libraries from two soybean cultivar (hairbin xiaoheidou, scn race 3 resistant, liaodou 10, scn race 3 susceptible) that grown under un-inoculated and s ... | 2012 | 22802924 |
| madp-rts: versatile virulence factors from bacterial pathogens of plants and mammals. | mono adp-ribosyltransferases (madp-rts) are a family of enzymes that cleave nad(+) and covalently attach the adp-ribosyl moiety to target proteins. madp-rts are well established as important virulence factors of bacteria that infect mammals. cholera toxin, pertussis toxin, and diphtheria toxin are three of the best-known examples of madp-rts. they modify host target proteins in order to promote infection and/or killing of the host cell. despite low sequence similarity at the primary amino acid l ... | 2012 | 22754560 |
| smaller fleas: viruses of microorganisms. | life forms can be roughly differentiated into those that are microscopic versus those that are not as well as those that are multicellular and those that, instead, are unicellular. cellular organisms seem generally able to host viruses, and this propensity carries over to those that are both microscopic and less than truly multicellular. these viruses of microorganisms, or voms, in fact exist as the world's most abundant somewhat autonomous genetic entities and include the viruses of domain bact ... | 2012 | 24278736 |
| widespread dynamic dna methylation in response to biotic stress. | regulation of gene expression by dna methylation is crucial for defining cellular identities and coordinating organism-wide developmental programs in many organisms. in plants, modulation of dna methylation in response to environmental conditions represents a potentially robust mechanism to regulate gene expression networks; however, examples of dynamic dna methylation are largely limited to gene imprinting. here we report an unexpected role for dna methylation in regulation of the arabidopsis t ... | 2012 | 22733782 |
| control of fusarium wilt in banana with chinese leek. | the inhibitory effects of chinese leek(allium tuberosum) on fusarium oxysporum f. sp. cubense (foc) and on fusarium wilt incidence were studied in order to identify a potential efficient way to control the disease. adopting the rotation system of chinese leek-banana reduced the fusarium wilt incidence and disease severity index by 88 %-97 % and 91 %-96 %, respectively, improved the crop value by 36 %-86 %, in an area heavily infested by foc between 2007 and 2009. as a result of inoculation in th ... | 2012 | 23144534 |
| oxidative stress and programmed cell death in yeast. | yeasts, such as saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies. this review will discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ros), their molecular targets, and the metabolic responses elicited by cellular ros accumulation. responses of yeast to accumulated ros include upregulation of antioxidants mediated by complex transcriptional changes, activ ... | 2012 | 22737670 |
| microbial population and community dynamics on plant roots and their feedbacks on plant communities. | the composition of the soil microbial community can be altered dramatically due to association with individual plant species, and these effects on the microbial community can have important feedbacks on plant ecology. negative plant-soil feedback plays primary roles in maintaining plant community diversity, whereas positive plant-soil feedback may cause community conversion. host-specific differentiation of the microbial community results from the trade-offs associated with overcoming plant defe ... | 2012 | 22726216 |
| an ultra-fast metabolite prediction algorithm. | small molecules are central to all biological processes and metabolomics becoming an increasingly important discovery tool. robust, accurate and efficient experimental approaches are critical to supporting and validating predictions from post-genomic studies. to accurately predict metabolic changes and dynamics, experimental design requires multiple biological replicates and usually multiple treatments. mass spectra from each run are processed and metabolite features are extracted. because of ma ... | 2012 | 22745711 |
| the coprs two-component system is responsible for resistance to copper in the cyanobacterium synechocystis sp. pcc 6803. | photosynthetic organisms need copper for cytochrome oxidase and for plastocyanin in the fundamental processes of respiration and photosynthesis. however, excess of free copper is detrimental inside the cells and therefore organisms have developed homeostatic mechanisms to tightly regulate its acquisition, sequestration, and efflux. herein we show that the coprs two-component system (also known as hik31-rre34) is essential for copper resistance in synechocystis sp. pcc 6803. it regulates expressi ... | 2012 | 22715108 |
| silencing nicotiana attenuata calcium-dependent protein kinases, cdpk4 and cdpk5, strongly up-regulates wound- and herbivory-induced jasmonic acid accumulations. | the plant hormone jasmonic acid (ja) plays a pivotal role in plant-insect interactions. herbivore attack usually elicits dramatic increases in ja concentrations, which in turn activate the accumulation of metabolites that function as defenses against herbivores. although almost all enzymes involved in the biosynthesis pathway of ja have been identified and characterized, the mechanism by which plants regulate ja biosynthesis remains unclear. calcium-dependent protein kinases (cdpks) are plant-sp ... | 2012 | 22715110 |
| molecular communications between plant heat shock responses and disease resistance. | as sessile, plants are continuously exposed to potential dangers including various abiotic stresses and pathogen attack. although most studies focus on plant responses under an ideal condition to a specific stimulus, plants in nature must cope with a variety of stimuli at the same time. this indicates that it is critical for plants to fine-control distinct signaling pathways temporally and spatially for simultaneous and effective responses to various stresses. global warming is currently a big i ... | 2012 | 22710621 |
| translocation of phospholipase a2α to apoplasts is modulated by developmental stages and bacterial infection in arabidopsis. | phospholipase a(2) (pla(2)) hydrolyzes phospholipids at the sn-2 position to yield lysophospholipids and free fatty acids. of the four paralogs expressed in arabidopsis, the cellular functions of pla(2)α in planta are poorly understood. the present study shows that pla(2)α possesses unique characteristics in terms of spatiotemporal subcellular localization, as compared with the other paralogs that remain in the er and/or golgi apparatus during secretory processes. only pla(2)α is secreted out to ... | 2012 | 22719742 |
| early senescence and cell death in arabidopsis saul1 mutants involves the pad4-dependent salicylic acid pathway. | age-dependent leaf senescence and cell death in arabidopsis (arabidopsis thaliana) requires activation of the transcription factor oresara1 (ore1) and is not initiated prior to a leaf age of 28 d. here, we investigate the conditional execution of events that regulate early senescence and cell death in senescence-associated ubiquitin ligase1 (saul1) mutants, deficient in the plant u-box-armadillo e3 ubiquitin ligase saul1. in saul1 mutants challenged with low light, the switch of age-dependent ce ... | 2012 | 22706448 |
| coronatine promotes pseudomonas syringae virulence in plants by activating a signaling cascade that inhibits salicylic acid accumulation. | phytopathogens can manipulate plant hormone signaling to access nutrients and counteract defense responses. pseudomonas syringae produces coronatine, a toxin that mimics the plant hormone jasmonic acid isoleucine and promotes opening of stomata for bacterial entry, bacterial growth in the apoplast, systemic susceptibility, and disease symptoms. we examined the mechanisms underlying coronatine-mediated virulence and show that coronatine activates three homologous nac transcription factor (tf) gen ... | 2012 | 22704619 |
| tomato tft1 is required for pamp-triggered immunity and mutations that prevent t3s effector xopn from binding to tft1 attenuate xanthomonas virulence. | xopn is a type iii effector protein from xanthomonas campestris pathovar vesicatoria that suppresses pamp-triggered immunity (pti) in tomato. previous work reported that xopn interacts with the tomato 14-3-3 isoform tft1; however, tft1's role in pti and/or xopn virulence was not determined. here we show that tft1 functions in pti and is a xopn virulence target. virus-induced gene silencing of tft1 mrna in tomato leaves resulted in increased growth of xcv δxopn and xcv δhrpf demonstrating that tf ... | 2012 | 22719257 |
| arabidopsis nonhost resistance gene pss1 confers immunity against an oomycete and a fungal pathogen but not a bacterial pathogen that cause diseases in soybean. | nonhost resistance (nhr) provides immunity to all members of a plant species against all isolates of a microorganism that is pathogenic to other plant species. three arabidopsis thaliana pen (penetration deficient) genes, pen1, 2 and 3 have been shown to provide nhr against the barley pathogen blumeria graminis f. sp. hordei at the prehaustorial level. arabidopsis pen1-1 mutant lacking the pen1 gene is penetrated by the hemibiotrophic oomycete pathogen phytophthora sojae, the causal organism of ... | 2012 | 22694952 |
| time for coffee represses accumulation of the myc2 transcription factor to provide time-of-day regulation of jasmonate signaling in arabidopsis. | plants are confronted with predictable daily biotic and abiotic stresses that result from the day-night cycle. the circadian clock provides an anticipation mechanism to respond to these daily stress signals to increase fitness. jasmonate (ja) is a phytohormone that mediates various growth and stress responses. here, we found that the circadian-clock component time for coffee (tic) acts as a negative factor in the ja-signaling pathway. we showed that the tic mutant is hypersensitive to growth-rep ... | 2012 | 22693280 |
| complexity of mirna-dependent regulation in root symbiosis. | the development of root systems may be strongly affected by the symbiotic interactions that plants establish with soil organisms. legumes are able to develop symbiotic relationships with both rhizobial bacteria and arbuscular mycorrhizal fungi leading to the formation of nitrogen-fixing nodules and mycorrhizal arbuscules, respectively. both of these symbiotic interactions involve complex cellular reprogramming and profound morphological and physiological changes in specific root cells. in additi ... | 2012 | 22527400 |
| isolation and characterization of endophytic bacteria isolated from the leaves of the common bean (phaseolus vulgaris). | the common bean is one of the most important legumes in the human diet, but little is known about the endophytic bacteria associated with the leaves of this plant. the objective of this study was to characterize the culturable endophytic bacteria of common bean (phaseolus vulgaris) leaves from three different cultivars (vermelhinho, talismã, and ouro negro) grown under the same field conditions. the density of endophytic populations varied from 4.5 x 10(2) to 2.8 x 10(3) cfu g(-1) of fresh weigh ... | 2012 | 24031988 |
| a deletion in the nitrate high affinity transporter nrt2.1 alters metabolomic and transcriptomic responses to pseudomonas syringae. | a deletion in the high affinity nitrate trasporter nrt2.1 in arabidopsis results in a reduced susceptibility to pseudomonas syringae by two different mechanisms, the sa priming and an interference in the effector triggered susceptibility. in the present research we further characterized the metabolic and genetic profiles of the mutant nrt2 in the interaction with p. syringae. despite the priming found in the sa-dependent pathway, the metabolic changes in nrt2 compared with wild-type plants are m ... | 2012 | 22580578 |
| the epigenetic machinery controlling transgenerational systemic acquired resistance. | progeny from diseased arabidopsis shows enhanced resistance, which is associated with priming of defense genes. this transgenerational systemic acquired resistance (sar) is effective against biotrophic pathogens, such as the downy mildew pathogen hyaloperonospora arabidopsidis. in this study, we have examined mutants in rna-directed dna methylation (rddm) for transgenerational sar. our analysis suggests that transgenerational sar is regulated by the rddm pathway and transmitted by hypomethylatio ... | 2012 | 22580690 |
| an overall evaluation of the resistance (r) and pathogenesis-related (pr) superfamilies in soybean, as compared with medicago and arabidopsis. | plants have the ability to recognize and respond to a multitude of pathogens, resulting in a massive reprogramming of the plant to activate defense responses including resistance (r) and pathogenesis-related (pr) genes. abiotic stresses can also activate pr genes and enhance pathogen resistance, representing valuable genes for breeding purposes. the present work offers an overview of soybean r and pr genes present in the genosoja (brazilian soybean genome consortium) platform, regarding their st ... | 2012 | 22802711 |
| ccrr, a tetr family transcriptional regulator, activates the transcription of a gene of the ethylmalonyl coenzyme a pathway in methylobacterium extorquens am1. | the ethylmalonyl coenzyme a (ethylmalonyl-coa) pathway is one of the central methylotrophy pathways in methylobacterium extorquens involved in glyoxylate generation and acetyl-coa assimilation. previous studies have elucidated the operation of the ethylmalonyl-coa pathway in c(1) and c(2) assimilation, but the regulatory mechanisms for the ethylmalonyl-coa pathway have not been reported. in this study, a tetr-type activator, ccrr, was shown to regulate the expression of crotonyl-coa reductase/ca ... | 2012 | 22447902 |
| type vi secretion system-associated gene clusters contribute to pathogenesis of salmonella enterica serovar typhimurium. | the enteropathogen salmonella enterica serovar typhimurium employs a suite of tightly regulated virulence factors within the intracellular compartment of phagocytic host cells resulting in systemic dissemination in mice. a type vi secretion system (t6ss) within salmonella pathogenicity island 6 (spi-6) has been implicated in this process; however, the regulatory inputs and the roles of noncore genes in this system are not well understood. here we describe four clusters of noncore t6ss genes in s ... | 2012 | 22493086 |