| e-2-hexenal promotes susceptibility to pseudomonas syringae by activating jasmonic acid pathways in arabidopsis. | green leaf volatiles (glvs) are c6-molecules - alcohols, aldehydes, and esters - produced by plants upon herbivory or during pathogen infection. exposure to this blend of volatiles induces defense-related responses in neighboring undamaged plants, thus assigning a role to glvs in regulating plant defenses. here we compared arabidopsis thaliana ecotype landsberg erecta (ler) with a hydroperoxide lyase line, hpl1, unable to synthesize glvs, for susceptibility to pseudomonas syringae pv. tomato (dc ... | 2013 | 23630530 |
| comparative transcriptome analysis of gossypium hirsutum l. in response to sap sucking insects: aphid and whitefly. | cotton (gossypium hirsutum l.) is a major fiber crop that is grown worldwide; it faces extensive damage from sap-sucking insects, including aphids and whiteflies. genome-wide transcriptome analysis was performed to understand the molecular details of interaction between gossypium hirsutum l. and sap-sucking pests, namely aphis gossypii (aphid) and bemisia tabacci (whiteflies). roche's gs-titanium was used to sequence transcriptomes of cotton infested with aphids and whiteflies for 2 h and 24 h. | 2013 | 23577705 |
| cell death control: the interplay of apoptosis and autophagy in the pathogenicity of sclerotinia sclerotiorum. | programmed cell death is characterized by a cascade of tightly controlled events that culminate in the orchestrated death of the cell. in multicellular organisms autophagy and apoptosis are recognized as two principal means by which these genetically determined cell deaths occur. during plant-microbe interactions cell death programs can mediate both resistant and susceptible events. via oxalic acid (oa), the necrotrophic phytopathogen sclerotinia sclerotiorum hijacks host pathways and induces ce ... | 2013 | 23592997 |
| a nuclear localization for avr2 from fusarium oxysporum is required to activate the tomato resistance protein i-2. | plant pathogens secrete effector proteins to promote host colonization. during infection of tomato xylem vessels, fusarium oxysporum f. sp. lycopersici (fol) secretes the avr2 effector protein. besides being a virulence factor, avr2 is recognized intracellularly by the tomato i-2 resistance protein, resulting in the induction of host defenses. here, we show that avr2 is highly expressed in root- and xylem-colonizing hyphae three days post inoculation of roots. co-expression of i-2 with avr2 dele ... | 2013 | 23596453 |
| antibacterial constituents of three cameroonian medicinal plants: garcinia nobilis, oricia suaveolens and balsamocitrus camerunensis. | multidrug resistance is a worrying cause of treatment failure in bacterial infections. the search of bioactive constituents from medicinal plants against multidrug resistant (mdr) bacteria has significantly evolved in the two last decades. in the present study, twenty-two compounds (three terpenoids, eleven phenolics and eight alkaloids) isolated from three cameroonian medicinal plants, namely garcinia nobilis, oricia suaveolens and balsamocitrus camerunensis, as well as the crude extracts were ... | 2013 | 23574627 |
| direct regulation of wrky70 by atmyb44 in plant defense responses. | cross-talk between hormones is required for plant response to developmental cues and environmental stresses. this cross-talk is achieved through several regulators located in convergence point of distinct hormonal signaling. in plant defense responses, salicylic acid and jasmonic acid affect each other in antagonistic manner. in a recent study we showed that atmyb44 transcription factor positively regulates sa-mediated defense expression and enhanced resistance to pst dc3000. on the other hand, ... | 2013 | 23603962 |
| differential requirement of oryza sativa rar1 in immune receptor-mediated resistance of rice to magnaporthe oryzae. | the required for mla12 resistance (rar1) protein is essential for the plant immune response. in rice, a model monocot species, the function of oryza sativa rar1 (osrar1) has been little explored. in our current study, we characterized the response of a rice osrar1 t-dna insertion mutant to infection by magnaporthe oryzae, the causal agent of rice blast disease. osrar1 mutants displayed reduced resistance compared with wild type rice when inoculated with the normally virulent m. oryzae isolate po ... | 2013 | 23563801 |
| modifying lignin to improve bioenergy feedstocks: strengthening the barrier against pathogens? | lignin is a ubiquitous polymer present in cell walls of all vascular plants, where it rigidifies and strengthens the cell wall structure through covalent cross-linkages to cell wall polysaccharides. the presence of lignin makes the cell wall recalcitrant to conversion into fermentable sugars for bioenergy uses. therefore, reducing lignin content and modifying its linkages have become major targets for bioenergy feedstock development through either biotechnology or traditional plant breeding. in ... | 2013 | 23577013 |
| diatom assemblages promote ice formation in large lakes. | we present evidence for the directed formation of ice by planktonic communities dominated by filamentous diatoms sampled from the ice-covered laurentian great lakes. we hypothesize that ice formation promotes attachment of these non-motile phytoplankton to overlying ice, thereby maintaining a favorable position for the diatoms in the photic zone. however, it is unclear whether the diatoms themselves are responsible for ice nucleation. scanning electron microscopy revealed associations of bacteri ... | 2013 | 23552624 |
| jasmonates: biosynthesis, perception, signal transduction and action in plant stress response, growth and development. an update to the 2007 review in annals of botany. | jasmonates are important regulators in plant responses to biotic and abiotic stresses as well as in development. synthesized from lipid-constituents, the initially formed jasmonic acid is converted to different metabolites including the conjugate with isoleucine. important new components of jasmonate signalling including its receptor were identified, providing deeper insight into the role of jasmonate signalling pathways in stress responses and development. | 2013 | 23558912 |
| the plant actin cytoskeleton responds to signals from microbe-associated molecular patterns. | plants are constantly exposed to a large and diverse array of microbes; however, most plants are immune to the majority of potential invaders and susceptible to only a small subset of pathogens. the cytoskeleton comprises a dynamic intracellular framework that responds rapidly to biotic stresses and supports numerous fundamental cellular processes including vesicle trafficking, endocytosis and the spatial distribution of organelles and protein complexes. for years, the actin cytoskeleton has bee ... | 2013 | 23593000 |
| a novel l-isoleucine-4'-dioxygenase and l-isoleucine dihydroxylation cascade in pantoea ananatis. | a unique operon structure has been identified in the genomes of several plant- and insect-associated bacteria. the distinguishing feature of this operon is the presence of tandem hila and hilb genes encoding dioxygenases belonging to the pf13640 and pf10014 (bsma) pfam families, respectively. the genes encoding hila and hilb from pantoea ananatis aj13355 were cloned and expressed in escherichia coli. the culturing of e. coli cells expressing hila (e. coli-hila) or both hila and hilb (e. coli-hil ... | 2013 | 23554367 |
| escherichia coli o157:h7 induces stronger plant immunity than salmonella enterica typhimurium sl1344. | consumption of fresh produce contaminated with bacterial human pathogens has resulted in various, sometimes deadly, disease outbreaks. in this study, we assessed plant defense responses induced by the fully pathogenic bacteria escherichia coli o157:h7 and salmonella enterica serovar typhimurium sl1344 in both arabidopsis thaliana and lettuce (lactuca sativa). unlike sl1344, o157:h7 induced strong plant immunity at both pre-invasion and post-invasion steps of infection. for instance, o157:h7 trig ... | 2013 | 23301812 |
| nonhost resistance of tomato to the bean pathogen pseudomonas syringae pv. syringae b728a is due to a defective e3 ubiquitin ligase domain in avrptobb728a. | the bean pathogen pseudomonas syringae pv. syringae b728a expresses homologs of the type iii effectors avrpto and avrptob, either of which can trigger resistance in tomato cultivars expressing pto and prf genes. we found that strain b728a also elicits nonhost resistance in tomato cultivars vfnt cherry and moneymaker that lack pto but express other members of the pto family (e.g., slfen and slptoc). here, we show that the avrptob homolog from b728a, termed avrptobb728a (also known as hopab1), is ... | 2013 | 23252461 |
| catalyzing plant science research with rna-seq. | next generation dna sequencing technologies are driving increasingly rapid, affordable and high resolution analyses of plant transcriptomes through sequencing of their associated cdna (complementary dna) populations; an analytical platform commonly referred to as rna-sequencing (rna-seq). since entering the arena of whole genome profiling technologies only a few years ago, rna-seq has proven itself to be a powerful tool with a remarkably diverse range of applications, from detailed studies of bi ... | 2013 | 23554602 |
| pseudomonas syringae pv. syringae uses proteasome inhibitor syringolin a to colonize from wound infection sites. | infection of plants by bacterial leaf pathogens at wound sites is common in nature. plants defend wound sites to prevent pathogen invasion, but several pathogens can overcome spatial restriction and enter leaf tissues. the molecular mechanisms used by pathogens to suppress containment at wound infection sites are poorly understood. here, we studied pseudomonas syringae strains causing brown spot on bean and blossom blight on pear. these strains exist as epiphytes that can cause disease upon woun ... | 2013 | 23555272 |
| a circadian clock-regulated toggle switch explains atgrp7 and atgrp8 oscillations in arabidopsis thaliana. | the circadian clock controls many physiological processes in higher plants and causes a large fraction of the genome to be expressed with a 24h rhythm. the transcripts encoding the rna-binding proteins atgrp7 (arabidopsis thaliana glycine rich protein 7) and atgrp8 oscillate with evening peaks. the circadian clock components cca1 and lhy negatively affect atgrp7 expression at the level of transcription. atgrp7 and atgrp8, in turn, negatively auto-regulate and reciprocally cross-regulate post-tra ... | 2013 | 23555221 |
| transcriptional profiling of rice early response to magnaporthe oryzae identified oswrkys as important regulators in rice blast resistance. | rice blast disease is a major threat to rice production worldwide, but the mechanisms underlying rice resistance to the causal agent magnaporthe oryzae remain elusive. therefore, we carried out a transcriptome study on rice early defense response to m. oryzae. we found that the transcriptional profiles of rice compatible and incompatible interactions with m. oryzae were mostly similar, with genes regulated more prominently in the incompatible interactions. the functional analysis showed that the ... | 2013 | 23544090 |
| characterization of aphanizomenon ovalisporum amidinotransferase involved in cylindrospermopsin synthesis. | an increasing abundance of aphanizomenon ovalisporum in water bodies from diverse world regions has been reported in the last few years, with the majority of the isolated strains producing the toxin cylindrospermopsin (cyn), leading to a rise in ecological and health risks. the understanding of cyn synthesis is crucial in the control of cyn production. an amidinotransferase (amdt) seems to be the first enzyme involved in the synthesis of cyn. in this study, we have cloned and overexpressed the a ... | 2013 | 23533111 |
| higher order asymptotics for negative binomial regression inferences from rna-sequencing data. | rna sequencing (rna-seq) is the current method of choice for characterizing transcriptomes and quantifying gene expression changes. this next generation sequencing-based method provides unprecedented depth and resolution. the negative binomial (nb) probability distribution has been shown to be a useful model for frequencies of mapped rna-seq reads and consequently provides a basis for statistical analysis of gene expression. negative binomial exact tests are available for two-group comparisons b ... | 2013 | 23502340 |
| alternative oxidase: a mitochondrial respiratory pathway to maintain metabolic and signaling homeostasis during abiotic and biotic stress in plants. | alternative oxidase (aox) is a non-energy conserving terminal oxidase in the plant mitochondrial electron transport chain. while respiratory carbon oxidation pathways, electron transport, and atp turnover are tightly coupled processes, aox provides a means to relax this coupling, thus providing a degree of metabolic homeostasis to carbon and energy metabolism. beside their role in primary metabolism, plant mitochondria also act as "signaling organelles", able to influence processes such as nucle ... | 2013 | 23531539 |
| multiple exoribonucleases catalyze maturation of the 3' terminus of 16s ribosomal rna (rrna). | processing of ribosomal rna (rrna) precursors is an important component of rna metabolism in all cells. however, in no system have we yet identified all the rnases involved in this process. here, we show that four 3'→5'-exoribonucleases, rnases ii, r, and ph, and polynucleotide phosphorylase (pnpase), participate in maturation of the 3' end of 16s rrna. in their absence, 16s precursor molecules with 33 extra 3'-nt accumulate; however, the presence of any one of the four rnases is sufficient to a ... | 2013 | 23532845 |
| raba members act in distinct steps of subcellular trafficking of the flagellin sensing2 receptor. | cell surface proteins play critical roles in the perception of environmental stimuli at the plasma membrane (pm) and ensuing signal transduction. intracellular localization of such proteins must be strictly regulated, which requires elaborate integration of exocytic and endocytic trafficking pathways. subcellular localization of arabidopsis thaliana flagellin sensing2 (fls2), a receptor that recognizes bacterial flagellin, also depends on membrane trafficking. however, our understanding about th ... | 2013 | 23532067 |
| br-signaling kinase1 physically associates with flagellin sensing2 and regulates plant innate immunity in arabidopsis. | pathogen-associated molecular pattern (pamp)-trigged immunity (pti) is the first defensive line of plant innate immunity and is mediated by pattern recognition receptors. here, we show that a mutation in br-signaling kinase1 (bsk1), a substrate of the brassinosteroid (br) receptor brassinosteroid insensitive1, suppressed the powdery mildew resistance caused by a mutation in enhanced disease resistance2, which negatively regulates powdery mildew resistance and programmed cell death, in arabidopsi ... | 2013 | 23532072 |
| in vitro gene silencing of independent phosphoglycerate mutase (ipgm) in the filarial parasite brugia malayi. | the phosphoglycerate mutase (pgm) enzyme catalyzes the interconversion of 2- and 3-phosphoglycerate in the glycolytic /gluconeogenic pathways that are present in the majority of cellular organisms. they can be classified as cofactor-dependent pgm (dpgm) or cofactor-independent pgm (ipgm). vertebrates, yeasts, and many bacteria have only dpgm, while higher plants, nematodes, archaea, and many other bacteria have only ipgm. a small number of bacteria, including escherichia coli and certain archaea ... | 2013 | 23849829 |
| purification and characterization of ases protein: a subtilisin secreted by acremonium strictum is a novel plant defense elicitor. | in this work, the purification and characterization of an extracellular elicitor protein, designated ases, produced by an avirulent isolate of the strawberry pathogen acremonium strictum, are reported. the defense eliciting activity present in culture filtrates was recovered and purified by ultrafiltration (cutoff, 30 kda), anionic exchange (q-sepharose, ph 7.5), and hydrophobic interaction (phenyl-sepharose) chromatographies. two-dimensional sds-page of the purified active fraction revealed a s ... | 2013 | 23530047 |
| combined roles of ethylene and endogenous peptides in regulating plant immunity and growth. | | 2013 | 23530253 |
| molecular signatures in arabidopsis thaliana in response to insect attack and bacterial infection. | under the threat of global climatic change and food shortages, it is essential to take the initiative to obtain a comprehensive understanding of common and specific defence mechanisms existing in plant systems for protection against different types of biotic invaders. we have implemented an integrated approach to analyse the overall transcriptomic reprogramming and systems-level defence responses in the model plant species arabidopsis thaliana (a. thaliana henceforth) during insect brevicoryne b ... | 2013 | 23536844 |
| phosphorylation of an erf transcription factor by arabidopsis mpk3/mpk6 regulates plant defense gene induction and fungal resistance. | arabidopsis thaliana mpk3 and mpk6, two mitogen-activated protein kinases (mapks or mpks), play critical roles in plant disease resistance by regulating multiple defense responses. previously, we characterized the regulation of phytoalexin biosynthesis by arabidopsis mpk3/mpk6 cascade and its downstream wrky33 transcription factor. here, we report another substrate of mpk3/mpk6, ethylene response factor6 (erf6), in regulating arabidopsis defense gene expression and resistance to the necrotrophic ... | 2013 | 23524660 |
| mrna export: threading the needle. | after mrna biogenesis, several proteins interact with the messenger to ensure its proper export to the cytoplasm. some of these proteins will bind rna early on, at the onset of transcription by rna polymerase ii holoenzyme, while others will join later for downstream processing steps, such as poly-adenylation or splicing, or may direct mrna ribonucleoprotein particle migration to the nucleopore. we recently discovered that arabidopsis plant knockout for the protein mos11 (modifier of snc1, 11) p ... | 2013 | 23526740 |
| metabolite profiling and biological activities of bioactive compounds produced by chrysosporium lobatum strain bk-3 isolated from kaziranga national park, assam, india. | in an ongoing survey for bioactive potential of microorganisms from different biosphere zones of india, a new chrysosporium lobatum strain bk-3 was isolated from soil sample collected from a biodiversity hotspot, kaziranga national park, assam, india. bioactivity-guided purification resulted in the isolation of two bioactive compounds whose chemical structures were elucidated by (1)h and (13)c nuclear magnetic resonance (nmr), 2d-nmr, fourier transform infra-red (ft-ir) and mass spectroscopic te ... | 2013 | 23565355 |
| recognition of bacterial plant pathogens: local, systemic and transgenerational immunity. | bacterial pathogens can cause multiple plant diseases and plants rely on their innate immune system to recognize and actively respond to these microbes. the plant innate immune system comprises extracellular pattern recognition receptors that recognize conserved microbial patterns and intracellular nucleotide binding leucine-rich repeat (nlr) proteins that recognize specific bacterial effectors delivered into host cells. plants lack the adaptive immune branch present in animals, but still afford ... | 2013 | 23909802 |
| xrn 5'→3' exoribonucleases: structure, mechanisms and functions. | the xrn family of 5'→3' exoribonucleases is critical for ensuring the fidelity of cellular rna turnover in eukaryotes. highly conserved across species, the family is typically represented by one cytoplasmic enzyme (xrn1/pacman or xrn4) and one or more nuclear enzymes (xrn2/rat1 and xrn3). cytoplasmic and/or nuclear xrns have proven to be essential in all organisms tested, and deficiencies can have severe developmental phenotypes, demonstrating that xrns are indispensable in fungi, plants and ani ... | 2013 | 23517755 |
| overexpression of the transcription factor rap2.6 leads to enhanced callose deposition in syncytia and enhanced resistance against the beet cyst nematode heterodera schachtii in arabidopsis roots. | cyst nematodes invade the roots of their host plants as second stage juveniles and induce a syncytium which is their source of nutrients throughout their life. a transcriptome analysis of syncytia induced by the beet cyst nematode heterodera schachtii in arabidopsis roots has shown that gene expression in the syncytium is different from that of the root with thousands of genes upregulated or downregulated. among the downregulated genes are many which code for defense-related proteins. one gene w ... | 2013 | 23510309 |
| an abscisic acid-independent oxylipin pathway controls stomatal closure and immune defense in arabidopsis. | plant stomata function in innate immunity against bacterial invasion and abscisic acid (aba) has been suggested to regulate this process. using genetic, biochemical, and pharmacological approaches, we demonstrate that (i) the arabidopsis thaliana nine-specific-lipoxygenase encoding gene, lox1, which is expressed in guard cells, is required to trigger stomatal closure in response to both bacteria and the pathogen-associated molecular pattern flagellin peptide flg22; (ii) lox1 participates in stom ... | 2013 | 23526882 |
| how plants shut out bacteria. | | 2013 | 23526883 |
| spatio-temporal expression patterns of arabidopsis thaliana and medicago truncatula defensin-like genes. | plant genomes contain several hundred defensin-like (defl) genes that encode short cysteine-rich proteins resembling defensins, which are well known antimicrobial polypeptides. little is known about the expression patterns or functions of many defls because most were discovered recently and hence are not well represented on standard microarrays. we designed a custom affymetrix chip consisting of probe sets for 317 and 684 defls from arabidopsis thaliana and medicago truncatula, respectively for ... | 2013 | 23527067 |
| mechanisms of small rna generation from cis-nats in response to environmental and developmental cues. | a large proportion of eukaryotic genomes is transcribed from both positive and negative strands of dna and thus may generate overlapping sense and antisense transcripts. some of these so-called natural antisense transcripts (nats) are possibly co-regulated. when the overlapping sense and antisense transcripts are expressed at the same time in the same cell in response to various developmental and environmental cues; they may form double-stranded rnas, which could be recognized by the small rna b ... | 2013 | 23505223 |
| advances in biotechnology and informatics to link variation in the genome to phenotypes in plants and animals. | advances in our understanding of genome structure provide consistent evidence for the existence of a core genome representing species classically defined by phenotype, as well as conditionally dispensable components of the genome that shows extensive variation between individuals of a given species. generally, conservation of phenotypic features between species reflects conserved features of the genome; however, this is evidently not necessarily always the case as demonstrated by the analysis of ... | 2013 | 23494190 |
| horizontal transfer of a subtilisin gene from plants into an ancestor of the plant pathogenic fungal genus colletotrichum. | the genus colletotrichum contains a large number of phytopathogenic fungi that produce enormous economic losses around the world. the effect of horizontal gene transfer (hgt) has not been studied yet in these organisms. inter-kingdom hgt into fungal genomes has been reported in the past but knowledge about the hgt between plants and fungi is particularly limited. we describe a gene in the genome of several species of the genus colletotrichum with a strong resemblance to subtilisins typically fou ... | 2013 | 23554975 |
| specialized roles of the conserved subunit ost3/6 of the oligosaccharyltransferase complex in innate immunity and tolerance to abiotic stresses. | asparagine-linked glycosylation of proteins is an essential cotranslational and posttranslational protein modification in plants. the central step in this process is the transfer of a preassembled oligosaccharide to nascent proteins in the endoplasmic reticulum by the oligosaccharyltransferase (ost) complex. despite the importance of the catalyzed reaction, the composition and the function of individual ost subunits are still ill defined in plants. here, we report the function of the highly cons ... | 2013 | 23493405 |
| characterization of five ecf sigma factors in the genome of pseudomonas syringae pv. syringae b728a. | pseudomonas syringae pv. syringae b728a, a bacterial pathogen of bean, utilizes large surface populations and extracellular signaling to initiate a fundamental change from an epiphytic to a pathogenic lifestyle. extracytoplasmic function (ecf) sigma (σ) factors serve as important regulatory factors in responding to various environmental signals. bioinformatic analysis of the b728a genome revealed 10 ecf sigma factors. this study analyzed deletion mutants of five previously uncharacterized ecf si ... | 2013 | 23516563 |
| trichoderma-plant root colonization: escaping early plant defense responses and activation of the antioxidant machinery for saline stress tolerance. | trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. microarrays analysis of arabidopsis thaliana roots inoculated with trichoderma asperelloides t203, coupled with qpcr analysis of 137 stress responsive genes and transcription factors, revealed wide gene transcript reprogramming, proceeded by a transient repression of the plant immune responses supposedly to allow root colonization. enhancement in the expression of wrky18 and wrky40, which ... | 2013 | 23516362 |
| transcriptomic analysis of the role of carboxylic acids in metabolite signaling in arabidopsis leaves. | the transcriptional response to metabolites is an important mechanism by which plants integrate information about cellular energy and nutrient status. although some carboxylic acids have been implicated in the regulation of gene expression for select transcripts, it is unclear whether all carboxylic acids have the same effect, how many transcripts are affected, and how carboxylic acid signaling is integrated with other metabolite signals. in this study, we demonstrate that perturbations in cellu ... | 2013 | 23487434 |
| della proteins and their interacting ring finger proteins repress gibberellin responses by binding to the promoters of a subset of gibberellin-responsive genes in arabidopsis. | della proteins, consisting of ga insensitive, repressor of ga1-3, rga-like1 (rgl1), rgl2, and rgl3, are central repressors of gibberellin (ga) responses, but their molecular functions are not fully understood. we isolated four della-interacting ring domain proteins, previously designated as botrytis susceptible1 interactor (boi), boi-related gene1 (brg1), brg2, and brg3 (collectively referred to as bois). single mutants of each boi gene failed to significantly alter ga responses, but the boi qua ... | 2013 | 23482857 |
| profligate biotin synthesis in α-proteobacteria - a developing or degenerating regulatory system? | biotin (vitamin h) is a key enzyme cofactor required in all three domains of life. although this cofactor was discovered over 70 years ago and has long been recognized as an essential nutrient for animals, our knowledge of the strategies bacteria use to sense biotin demand is very limited. the paradigm mechanism is that of escherichia coli in which bira protein, the prototypical bi-functional biotin protein ligase, both covalently attaches biotin to the acceptor proteins of central metabolism an ... | 2013 | 23387333 |
| de-novo assembly and characterization of the transcriptome of metschnikowia fructicola reveals differences in gene expression following interaction with penicillium digitatum and grapefruit peel. | the yeast metschnikowia fructicola is an antagonist with biological control activity against postharvest diseases of several fruits. we performed a transcriptome analysis, using rna-seq technology, to examine the response of m. fructicola with citrus fruit and with the postharvest pathogen, penicillium digitatum. | 2013 | 23496978 |
| context-dependent protein folding of a virulence peptide in the bacterial and host environments: structure of an sych-yoph chaperone-effector complex. | yersinia pestis injects numerous bacterial proteins into host cells through an organic nanomachine called the type 3 secretion system. one such substrate is the tyrosine phosphatase yoph, which requires an interaction with a cognate chaperone in order to be effectively injected. here, the first crystal structure of a sych-yoph complex is reported, determined to 1.9 å resolution. the structure reveals the presence of (i) a nonglobular polypeptide in yoph, (ii) a so-called β-motif in yoph and (iii ... | 2013 | 23519663 |
| pskr1 and psy1r-mediated regulation of plant defense responses. | plant peptide signaling is an upcoming topic in many areas of plant research. our recent findings show that the tyrosine sulfated peptide receptors pskr1 and psy1r are not only involved in growth and development but also in plant defense. they modulate salicylate- and jasmonate-dependent defense pathways in an antagonistic manner and this phenomenon might be dependent on the age and developmental stage of the plant. here we discuss how the endogenous peptides might integrate growth, wounding, se ... | 2013 | 23470723 |
| arabidopsis and brachypodium distachyon transgenic plants expressing aspergillus nidulans acetylesterases have decreased degree of polysaccharide acetylation and increased resistance to pathogens. | the plant cell wall has many significant structural and physiological roles, but the contributions of the various components to these roles remain unclear. modification of cell wall properties can affect key agronomic traits such as disease resistance and plant growth. the plant cell wall is composed of diverse polysaccharides often decorated with methyl, acetyl, and feruloyl groups linked to the sugar subunits. in this study, we examined the effect of perturbing cell wall acetylation by making ... | 2013 | 23463782 |
| bioactive flavanoids from glycosmis arborea. | glycosmis is a genus of evergreen glabrous shrub and distributed all over india. it possesses various medicinal properties and is used in indigenous medicine for cough, rheumatism, anemia, and jaundice. glycosmis arborea is a rich source of alkaloids, terpenoids, coumarins, as well as flavonoids. | 2013 | 23497605 |
| synthetic molecules: helping to unravel plant signal transduction. | the application of small molecules has played a crucial role in identifying novel components involved in plant signalling. compared to classic genetic approaches, small molecule screens offer notable advantages in dissecting plant biological processes, such as technical simplicity, low start-up costs, and most importantly, bypassing the problems of lethality and redundancy. to identify small molecules that target a biological process or protein of interest, robust and well-reasoned high-throughp ... | 2013 | 24432124 |
| theobroxide treatment inhibits wild fire disease occurrence in nicotiana benthamiana by the overexpression of defense-related genes. | theobroxide, a novel compound isolated from a fungus lasiodiplodia theobromae, stimulates potato tuber formation and induces flowering of morning glory by initiating the jasmonic acid synthesis pathway. to elucidate the effect of theobroxide on pathogen resistance in plants, nicotiana benthamiana plants treated with theobroxide were immediately infiltrated with pseudomonas syringae pv. tabaci. exogenous application of theobroxide inhibited development of lesion symptoms, and growth of the bacter ... | 2013 | 25288936 |
| heterotrimeric g protein signalling in the plant kingdom. | in animals, heterotrimeric g proteins, comprising α-, β-and γ-subunits, perceive extracellular stimuli through cell surface receptors, and transmit signals to ion channels, enzymes and other effector proteins to affect numerous cellular behaviours. in plants, g proteins have structural similarities to the corresponding molecules in animals but transmit signals by atypical mechanisms and effector proteins to control growth, cell proliferation, defence, stomate movements, channel regulation, sugar ... | 2013 | 23536550 |
| the shigella type three secretion system effector ospg directly and specifically binds to host ubiquitin for activation. | the genus shigella infects human gut epithelial cells to cause diarrhea and gastrointestinal disorders. like many other gram-negative bacterial pathogens, the virulence of shigella spp. relies on a conserved type three secretion system that delivers a handful of effector proteins into host cells to manipulate various host cell physiology. however, many of the shigella type iii effectors remain functionally uncharacterized. here we observe that ospg, one of the shigella effectors, interacted with ... | 2013 | 23469023 |
| a genome-wide analysis of the lbd (lateral organ boundaries domain) gene family in malus domestica with a functional characterization of mdlbd11. | the plant-specific lbd (lateral organ boundaries domain) genes belong to a major family of transcription factor that encode a zinc finger-like domain. it has been shown that lbd genes play crucial roles in the growth and development of arabidopsis and other plant species. however, no detailed information concerning this family is available for apple. in the present study, we analyzed the apple (malus domestica) genome and identified 58 lbd genes. this gene family was tested for its phylogenetic ... | 2013 | 23468909 |
| mutualistic co-evolution of type iii effector genes in sinorhizobium fredii and bradyrhizobium japonicum. | two diametric paradigms have been proposed to model the molecular co-evolution of microbial mutualists and their eukaryotic hosts. in one, mutualist and host exhibit an antagonistic arms race and each partner evolves rapidly to maximize their own fitness from the interaction at potential expense of the other. in the opposing model, conflicts between mutualist and host are largely resolved and the interaction is characterized by evolutionary stasis. we tested these opposing frameworks in two line ... | 2013 | 23468637 |
| phytopathogen type iii effectors as probes of biological systems. | bacterial phytopathogens utilize a myriad of virulence factors to modulate their plant hosts in order to promote successful pathogenesis. one potent virulence strategy is to inject these virulence proteins into plant cells via the type iii secretion system. characterizing the host targets and the molecular mechanisms of type iii secreted proteins, known as effectors, has illuminated our understanding of eukaryotic cell biology. as a result, these effectors can serve as molecular probes to aid in ... | 2013 | 23433088 |
| genetic and genomic analysis of rhizoctonia solani interactions with arabidopsis; evidence of resistance mediated through nadph oxidases. | rhizoctonia solani is an important soil-borne necrotrophic fungal pathogen, with a broad host range and little effective resistance in crop plants. arabidopsis is resistant to r. solani ag8 but susceptible to r. solani ag2-1. a screen of 36 arabidopsis ecotypes and mutants affected in the auxin, camalexin, salicylic acid, abscisic acid and ethylene/jasmonic acid pathways did not reveal any variation in response to r. solani and demonstrated that resistance to ag8 was independent of these defense ... | 2013 | 23451091 |
| proteomic insights into intra- and intercellular plant-bacteria symbiotic association during root nodule formation. | over the last several decades, there have been a large number of studies done on the all aspects of legumes and bacteria which participate in nitrogen-fixing symbiosis. the analysis of legume-bacteria interaction is not just a matter of numerical complexity in terms of variants of gene products that can arise from a single gene. bacteria regulate their quorum-sensing genes to enhance their ability to induce conjugation of plasmids and symbiotic islands, and various protein secretion mechanisms; ... | 2013 | 23443347 |
| protein tyrosine nitration in higher plants grown under natural and stress conditions. | protein tyrosine nitration is a post-translational modification (ptm) mediated by reactive nitrogen species (rns) that is linked to nitro-oxidative damages in plant cells. during the last decade, the identification of proteins undergoing this ptm under adverse environmental conditions has increased. however, there is also a basal endogenous nitration which seems to have a regulatory function. the technological advances in proteome analysis have allowed identifying these modified proteins and hav ... | 2013 | 23444154 |
| competition and the origins of novelty: experimental evolution of niche-width expansion in a virus. | competition for resources has long been viewed as a key agent of divergent selection. theory holds that populations facing severe intraspecific competition will tend to use a wider range of resources, possibly even using entirely novel resources that are less in demand. yet, there have been few experimental tests of these ideas. using the bacterial virus (bacteriophage) 6 as a model system, we examined whether competition for host resources promotes the evolution of novel resource use. in the la ... | 2013 | 23075527 |
| the arabidopsis elongator complex subunit2 epigenetically regulates plant immune responses. | the arabidopsis thaliana elongator complex subunit2 (elp2) genetically interacts with nonexpressor of pathogenesis-related genes1 (npr1), a key transcription coactivator of plant immunity, and regulates the induction kinetics of defense genes. however, the mechanistic relationship between elp2 and npr1 and how elp2 regulates the kinetics of defense gene induction are unclear. here, we demonstrate that elp2 is an epigenetic regulator required for pathogen-induced rapid transcriptome reprogramming ... | 2013 | 23435660 |
| salicylic acid suppresses jasmonic acid signaling downstream of scfcoi1-jaz by targeting gcc promoter motifs via transcription factor ora59. | antagonism between the defense hormones salicylic acid (sa) and jasmonic acid (ja) plays a central role in the modulation of the plant immune signaling network, but the molecular mechanisms underlying this phenomenon are largely unknown. here, we demonstrate that suppression of the ja pathway by sa functions downstream of the e3 ubiquitin-ligase skip-cullin-f-box complex scf(coi1), which targets jasmonate zim-domain transcriptional repressor proteins (jazs) for proteasome-mediated degradation. i ... | 2013 | 23435661 |
| using fundamental knowledge of induced resistance to develop control strategies for bacterial canker of kiwifruit caused by pseudomonas syringae pv. actinidiae. | | 2013 | 23437017 |
| nuclear dynamics of arabidopsis calcium-dependent protein kinases in effector-triggered immunity. | plants have evolved sophisticated innate immune systems to protect themselves from potential microbial invasions. recognition of pathogen-derived virulence effector proteins is mediated by plant resistance (r) proteins and elicits potent defense responses, collectively termed as effector-triggered immunity (eti). it has long been known that eti is often accompanied with the increase of cytosolic ca(2+) levels. we recently identified six closely related calcium-dependent protein kinases (cpks) in ... | 2013 | 23425856 |
| plant-associated bacteria and their role in the success or failure of metal phytoextraction projects: first observations of a field-related experiment. | phytoextraction has been reported as an economically and ecologically sound alternative for the remediation of metal-contaminated soils. willow is a metal phytoextractor of interest because it allows to combine a gradual contaminant removal with production of biomass that can be valorized in different ways. in this work two willow clones growing on a metal-contaminated site were selected: 'belgisch rood' (br) with a moderate metal extraction capacity and 'tora' (to) with a twice as high metal ac ... | 2013 | 23425076 |
| layered pattern receptor signaling via ethylene and endogenous elicitor peptides during arabidopsis immunity to bacterial infection. | recognition of molecular patterns characteristic of microbes or altered-self leads to immune activation in multicellular eukaryotes. in arabidopsis thaliana, the leucine-rich-repeat receptor kinases flagellin-sensing2 (fls2) and ef-tu receptor (efr) recognize bacterial flagellin and elongation factor ef-tu (and their elicitor-active epitopes flg22 and elf18), respectively. likewise, pep1 receptor1 (pepr1) and pepr2 recognize the elicitor-active pep epitopes conserved in arabidopsis elicitor pept ... | 2013 | 23431187 |
| heterotrimeric g proteins serve as a converging point in plant defense signaling activated by multiple receptor-like kinases. | in fungi and metazoans, extracellular signals are often perceived by g-protein-coupled receptors (gpcrs) and transduced through heterotrimeric g-protein complexes to downstream targets. plant heterotrimeric g proteins are also involved in diverse biological processes, but little is known about their upstream receptors. moreover, the presence of bona fide gpcrs in plants is yet to be established. in arabidopsis (arabidopsis thaliana), heterotrimeric g protein consists of one gα subunit (g protein ... | 2013 | 23424249 |
| the deinococcus radiodurans dr1245 protein, a ddrb partner homologous to ybjn proteins and reminiscent of type iii secretion system chaperones. | the bacterium deinococcus radiodurans exhibits an extreme resistance to ionizing radiation. a small subset of deinococcus genus-specific genes were shown to be up-regulated upon exposure to ionizing radiation and to play a role in genome reconstitution. these genes include an ssb-like protein called ddrb. here, we identified a novel protein encoded by the dr1245 gene as an interacting partner of ddrb. a strain devoid of the dr1245 protein is impaired in growth, exhibiting a generation time appro ... | 2013 | 23441204 |
| structure of ldtmt2, an l,d-transpeptidase from mycobacterium tuberculosis. | the transpeptidase ltdmt2 catalyzes the formation of the (3-3) cross-links characteristic of the peptidoglycan layer in the mycobacterium tuberculosis cell wall. bioinformatics analysis suggests that the extramembrane part of the enzyme consists of three domains: two smaller domains (denoted as a and b domains) and a transpeptidase domain (the c domain) at the c-terminus. the crystal structures of two fragments comprising the ab domains and the bc domains have been determined. the structure of t ... | 2013 | 23519418 |
| the pseudomonas syringae effector hopq1 promotes bacterial virulence and interacts with tomato 14-3-3 proteins in a phosphorylation-dependent manner. | a key virulence strategy of bacterial pathogens is the delivery of multiple pathogen effector proteins into host cells during infection. the hrp outer protein q (hopq1) effector from pseudomonas syringae pv tomato (pto) strain dc3000 is conserved across multiple bacterial plant pathogens. here, we investigated the virulence function and host targets of hopq1 in tomato (solanum lycopersicum). transgenic tomato lines expressing dexamethasone-inducible hopq1 exhibited enhanced disease susceptibilit ... | 2013 | 23417089 |
| a modular cell-based biosensor using engineered genetic logic circuits to detect and integrate multiple environmental signals. | cells perceive a wide variety of cellular and environmental signals, which are often processed combinatorially to generate particular phenotypic responses. here, we employ both single and mixed cell type populations, pre-programmed with engineered modular cell signalling and sensing circuits, as processing units to detect and integrate multiple environmental signals. based on an engineered modular genetic and logic gate, we report the construction of a set of scalable synthetic microbe-based bio ... | 2013 | 22981411 |
| sugars, the clock and transition to flowering. | sugars do not only act as source of energy, but they also act as signals in plants. this mini review summarizes the emerging links between sucrose-mediated signaling and the cellular networks involved in flowering time control and defense. cross-talks with gibberellin and jasmonate signaling pathways are highlighted. the circadian clock fulfills a crucial role at the heart of cellular networks and the bilateral relation between sugar signaling and the clock is discussed. it is proposed that impo ... | 2013 | 23420760 |
| the cytoskeleton is disrupted by the bacterial effector hrpz, but not by the bacterial pamp flg22, in tobacco by-2 cells. | plant innate immunity is composed of two layers. basal immunity is triggered by pathogen-associated molecular patterns (pamps) such as the flagellin-peptide flg22 and is termed pamp-triggered immunity (pti). in addition, effector-triggered immunity (eti) linked with programmed cell death and cytoskeletal reorganization can be induced by pathogen-derived factors, such as the harpin proteins originating from phytopathogenic bacteria. to get insight into the link between cytoskeleton and pti or eti ... | 2013 | 23408828 |
| coronatine inhibits stomatal closure and delays hypersensitive response cell death induced by nonhost bacterial pathogens. | pseudomonas syringae is the most widespread bacterial pathogen in plants. several strains of p. syringae produce a phytotoxin, coronatine (cor), which acts as a jasmonic acid mimic and inhibits plant defense responses and contributes to disease symptom development. in this study, we found that cor inhibits early defense responses during nonhost disease resistance. stomatal closure induced by a nonhost pathogen, p. syringae pv. tabaci, was disrupted by cor in tomato epidermal peels. in addition, ... | 2013 | 23638370 |
| reduced expression of glycolate oxidase leads to enhanced disease resistance in rice. | glycolate oxidase (glo) is a key enzyme in photorespiration, catalyzing the oxidation of glycolate to glyoxylate. arabidopsis glo is required for nonhost defense responses to pseudomonas syringae and for tobacco pto/avrpto-mediated defense responses. we previously described identification of rice glo1 that interacts with a glutaredoxin protein, which in turn interacts with tga transcription factors. tga transcription factors are well known to participate in npr1/nh1-mediated defense signaling, w ... | 2013 | 23638363 |
| the rab gtpase rabg3b positively regulates autophagy and immunity-associated hypersensitive cell death in arabidopsis. | a central component of the plant defense response to pathogens is the hypersensitive response (hr), a form of programmed cell death (pcd). rapid and localized induction of hr pcd ensures that pathogen invasion is prevented. autophagy has been implicated in the regulation of hr cell death, but the functional relationship between autophagy and hr pcd and the regulation of these processes during the plant immune response remain controversial. here, we show that a small gtp-binding protein, rabg3b, ... | 2013 | 23404918 |
| description of plant trna-derived rna fragments (trfs) associated with argonaute and identification of their putative targets. | trna-derived rna fragments (trfs) are 19mer small rnas that associate with argonaute (ago) proteins in humans. however, in plants, it is unknown if trfs bind with ago proteins. here, using public deep sequencing libraries of immunoprecipitated argonaute proteins (ago-ip) and bioinformatics approaches, we identified the arabidopsis thaliana ago-ip trfs. moreover, using three degradome deep sequencing libraries, we identified four putative trf targets. the expression pattern of trfs, based on deep ... | 2013 | 23402430 |
| epidemiological study of hazelnut bacterial blight in central italy by using laboratory analysis and geostatistics. | incidence of xanthomonas arboricola pv. corylina, the causal agent of hazelnut bacterial blight, was analyzed spatially in relation to the pedoclimatic factors. hazelnut grown in twelve municipalities situated in the province of viterbo, central italy was studied. a consistent number of bacterial isolates were obtained from the infected tissues of hazelnut collected in three years (2010-2012). the isolates, characterized by phenotypic tests, did not show any difference among them. spatial patter ... | 2013 | 23424654 |
| acclimation responses of arabidopsis thaliana to sustained phosphite treatments. | phosphite (h₂po⁻₃) induces a range of physiological and developmental responses in plants by disturbing the homeostasis of the macronutrient phosphate. because of its close structural resemblance to phosphate, phosphite impairs the sensing, membrane transport, and subcellular compartmentation of phosphate. in addition, phosphite induces plant defence responses by an as yet unknown mode of action. in this study, the acclimation of arabidopsis thaliana plants to a sustained phosphite supply in the ... | 2013 | 23404904 |
| the anticipation of danger: microbe-associated molecular pattern perception enhances atpep-triggered oxidative burst. | the endogenous arabidopsis (arabidopsis thaliana) peptides, atpeps, elicit an innate immune response reminiscent of pattern-triggered immunity. detection of various danger signals, including microbe-associated molecular patterns (mamps), leads to elevated transcription of propeps, the atpep precursors, and peprs, the atpep receptors. it has been hypothesized that atpeps are involved in enhancing pattern-triggered immunity. following this idea, we analyzed the relationship between mamp- and atpep ... | 2013 | 23400703 |
| pseudomonas hopu1 modulates plant immune receptor levels by blocking the interaction of their mrnas with grp7. | pathogens target important components of host immunity to cause disease. the pseudomonas syringae type iii-secreted effector hopu1 is a mono-adp-ribosyltransferase required for full virulence on arabidopsis thaliana. hopu1 targets several rna-binding proteins including grp7, whose role in immunity is still unclear. here, we show that grp7 associates with translational components, as well as with the pattern recognition receptors fls2 and efr. moreover, grp7 binds specifically fls2 and efr transc ... | 2013 | 23395902 |
| engineered resistance and hypersusceptibility through functional metabolic studies of 100 genes in soybean to its major pathogen, the soybean cyst nematode. | during pathogen attack, the host plant induces genes to ward off the pathogen while the pathogen often produces effector proteins to increase susceptibility of the host. gene expression studies of syncytia formed in soybean root by soybean cyst nematode (heterodera glycines) identified many genes altered in expression in resistant and susceptible roots. however, it is difficult to assess the role and impact of these genes on resistance using gene expression patterns alone. we selected 100 soybea ... | 2013 | 23389673 |
| dna methylation mediated control of gene expression is critical for development of crown gall tumors. | crown gall tumors develop after integration of the t-dna of virulent agrobacterium tumefaciens strains into the plant genome. expression of the t-dna-encoded oncogenes triggers proliferation and differentiation of transformed plant cells. crown gall development is known to be accompanied by global changes in transcription, metabolite levels, and physiological processes. high levels of abscisic acid (aba) in crown galls regulate expression of drought stress responsive genes and mediate drought st ... | 2013 | 23408907 |
| the epiphytic fungus pseudozyma aphidis induces jasmonic acid- and salicylic acid/nonexpressor of pr1-independent local and systemic resistance. | pseudozyma spp. are yeast-like fungi, classified in the ustilaginales, which are mostly epiphytic or saprophytic and are not pathogenic to plants. several pseudozyma species have been reported to exhibit biological activity against powdery mildews. however, previous studies have reported that pseudozyma aphidis, which can colonize plant surfaces, is not associated with the collapse of powdery mildew colonies. in this report, we describe a novel p. aphidis strain and study its interactions with i ... | 2013 | 23388119 |
| enhanced botrytis cinerea resistance of arabidopsis plants grown in compost may be explained by increased expression of defense-related genes, as revealed by microarray analysis. | composts are the products obtained after the aerobic degradation of different types of organic matter waste and can be used as substrates or substrate/soil amendments for plant cultivation. there is a small but increasing number of reports that suggest that foliar diseases may be reduced when using compost, rather than standard substrates, as growing medium. the purpose of this study was to examine the gene expression alteration produced by the compost to gain knowledge of the mechanisms involve ... | 2013 | 23405252 |
| developmental and environmental regulation of aquaporin gene expression across populus species: divergence or redundancy? | aquaporins (aqps) are membrane channels belonging to the major intrinsic proteins family and are known for their ability to facilitate water movement. while in populus trichocarpa, aqp proteins form a large family encompassing fifty-five genes, most of the experimental work focused on a few genes or subfamilies. the current work was undertaken to develop a comprehensive picture of the whole aqp gene family in populus species by delineating gene expression domain and distinguishing responsiveness ... | 2013 | 23393587 |
| activation of defense mechanisms against pathogens in mosses and flowering plants. | during evolution, plants have developed mechanisms to cope with and adapt to different types of stress, including microbial infection. once the stress is sensed, signaling pathways are activated, leading to the induced expression of genes with different roles in defense. mosses (bryophytes) are non-vascular plants that diverged from flowering plants more than 450 million years ago, allowing comparative studies of the evolution of defense-related genes and defensive metabolites produced after mic ... | 2013 | 23380962 |
| a novel peroxidase canpod gene of pepper is involved in defense responses to phytophtora capsici infection as well as abiotic stress tolerance. | peroxidases are involved in many plant processes including plant defense responses to biotic and abiotic stresses. we isolated a novel peroxidase gene canpod from leaves of pepper cultivar a3. the full-length gene has a 1353-bp cdna sequence and contains an open reading frame (orf) of 975-bp, which encodes a putative polypeptide of 324 amino acids with a theoretical protein size of 34.93 kda. canpod showed diverse expression levels in different tissues of pepper plants. to evaluate the role of c ... | 2013 | 23380961 |
| differential contribution of transcription factors to arabidopsis thaliana defense against spodoptera littoralis. | in response to insect herbivory, arabidopsis plants activate the synthesis of the phytohormone jasmonate-isoleucine, which binds to a complex consisting of the receptor coi1 and jaz repressors. upon proteasome-mediated jaz degradation, basic helix-loop-helix transcription factors (tfs) myc2, myc3, and myc4 become activated and this results in the expression of defense genes. although the jasmonate (ja) pathway is known to be essential for the massive transcriptional reprogramming that follows he ... | 2013 | 23382734 |
| genomic era analyses of rna secondary structure and rna-binding proteins reveal their significance to post-transcriptional regulation in plants. | the eukaryotic transcriptome is regulated both transcriptionally and post-transcriptionally. transcriptional control was the major focus of early research efforts, while more recently post-transcriptional mechanisms have gained recognition for their significant regulatory importance. at the heart of post-transcriptional regulatory pathways are cis- and trans-acting features and factors including rna secondary structure as well as rna-binding proteins and their recognition sites on target rnas. r ... | 2013 | 23498863 |
| the mangotoxin biosynthetic operon (mbo) is specifically distributed within pseudomonas syringae genomospecies 1 and was acquired only once during evolution. | mangotoxin production was first described in pseudomonas syringae pv. syringae strains. a phenotypic characterization of 94 p. syringae strains was carried out to determine the genetic evolution of the mangotoxin biosynthetic operon (mbo). we designed a pcr primer pair specific for the mbo operon to examine its distribution within the p. syringae complex. these primers amplified a 692-bp dna fragment from 52 mangotoxin-producing strains and from 7 non-mangotoxin-producing strains that harbor the ... | 2013 | 23144138 |
| diverse microhabitats experienced by halomonas variabilis on salt-secreting leaves. | the leaf surfaces of the salt-excreting tree tamarix aphylla harbor a wide diversity of halophilic microorganisms, including halomonas sp., but little is known of the factors that shape community composition in this extreme habitat. we isolated a strain of halomonas variabilis from the leaf surface of t. aphylla and used it to determine the heterogeneity of salt concentrations experienced by bacteria in this environment. this halophilic strain was transformed with a prou::gfp reporter gene fusio ... | 2013 | 23160133 |
| structure of the hopa1(21-102)-shca chaperone-effector complex of pseudomonas syringae reveals conservation of a virulence factor binding motif from animal to plant pathogens. | pseudomonas syringae injects numerous bacterial proteins into host plant cells through a type 3 secretion system (t3ss). one of the first such bacterial effectors discovered, hopa1, is a protein that has unknown functions in the host cell but possesses close homologs that trigger the plant hypersensitive response in resistant strains. like the virulence factors in many bacterial pathogens of animals, hopa1 depends upon a cognate chaperone in order to be effectively translocated by the p. syringa ... | 2013 | 23204470 |
| the tomato prf complex is a molecular trap for bacterial effectors based on pto transphosphorylation. | the major virulence strategy of phytopathogenic bacteria is to secrete effector proteins into the host cell to target the immune machinery. avrpto and avrptob are two such effectors from pseudomonas syringae, which disable an overlapping range of kinases in arabidopsis and tomato. both effectors target surface-localized receptor-kinases to avoid bacterial recognition. in turn, tomato has evolved an intracellular effector-recognition complex composed of the nb-lrr protein prf and the pto kinase. ... | 2013 | 23382672 |
| bifurcation of arabidopsis nlr immune signaling via ca²⁺-dependent protein kinases. | nucleotide-binding domain leucine-rich repeat (nlr) protein complexes sense infections and trigger robust immune responses in plants and humans. activation of plant nlr resistance (r) proteins by pathogen effectors launches convergent immune responses, including programmed cell death (pcd), reactive oxygen species (ros) production and transcriptional reprogramming with elusive mechanisms. functional genomic and biochemical genetic screens identified six closely related arabidopsis ca²⁺-dependent ... | 2013 | 23382673 |
| multiple phytohormone signalling pathways modulate susceptibility of tomato plants to alternaria alternata f. sp. lycopersici. | three phytohormone molecules - ethylene (et), jasmonic acid (ja) and salicylic acid (sa) - play key roles in mediating disease response to necrotrophic fungal pathogens. this study investigated the roles of the et, ja, and sa pathways as well as their crosstalk during the interaction between tomato (solanum lycopersicum) plants and a necrotrophic fungal pathogen alternaria alternata f. sp. lycopersici (aal). both the et and jasmonic acid insensitive1 (jai1) receptor-dependent ja signalling pathw ... | 2013 | 23264518 |
| disease resistance gene-induced growth inhibition is enhanced by rcd1 independent of defense activation in arabidopsis. | activation of plant immune responses is often associated with an inhibition of plant growth. the molecular mechanisms underlying this fitness cost are unknown. here, we utilize the autoimmune response mutant suppressor of npr1, constitutive1 (snc1) resulting from an activated form of the disease resistance (r) gene to dissect the genetic component mediating growth inhibition in arabidopsis (arabidopsis thaliana). the radical-induced cell death1 (rcd1) mutant defective in responses to reactive ox ... | 2013 | 23365132 |
| sticking together: building a biofilm the bacillus subtilis way. | biofilms are ubiquitous communities of tightly associated bacteria encased in an extracellular matrix. bacillus subtilis has long served as a robust model organism to examine the molecular mechanisms of biofilm formation, and a number of studies have revealed that this process is regulated by several integrated pathways. in this review, we focus on the molecular mechanisms that control b. subtilis biofilm assembly, and then briefly summarize the current state of knowledge regarding biofilm disas ... | 2013 | 23353768 |