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asymmetric chromosome segregation in xanthomonas citri ssp. citri.this study was intended to characterize the chromosome segregation process of xanthomonas citri ssp. citri (xac) by investigating the functionality of the parb factor encoded on its chromosome, and its requirement for cell viability and virulence. using tap tagging we show that parb is expressed in xac. disruption of parb increased the cell doubling time and precluded the ability of xac to colonize the host citrus. moreover, xac mutant cells expressing only truncated forms of parb exhibited the ...201324339434
structural and physiological analyses of the alkanesulphonate-binding protein (ssua) of the citrus pathogen xanthomonas citri.the uptake of sulphur-containing compounds plays a pivotal role in the physiology of bacteria that live in aerobic soils where organosulfur compounds such as sulphonates and sulphate esters represent more than 95% of the available sulphur. until now, no information has been available on the uptake of sulphonates by bacterial plant pathogens, particularly those of the xanthomonas genus, which encompasses several pathogenic species. in the present study, we characterised the alkanesulphonate uptak ...201324282519
the role of semidisorder in temperature adaptation of bacterial flgm proteins.probabilities of disorder for flgm proteins of 39 species whose optimal growth temperature ranges from 273 k (0°c) to 368 k (95°c) were predicted by a newly developed method called sequence-based prediction with integrated neural networks for disorder (spine-d). we showed that the temperature-dependent behavior of flgm proteins could be separated into two subgroups according to their sequence lengths. only shorter sequences evolved to adapt to high temperatures (>318 k or 45°c). their ability to ...201324314090
the lov protein of xanthomonas citri subsp. citri plays a significant role in the counteraction of plant immune responses during citrus canker.pathogens interaction with a host plant starts a set of immune responses that result in complex changes in gene expression and plant physiology. light is an important modulator of plant defense response and recent studies have evidenced the novel influence of this environmental stimulus in the virulence of several bacterial pathogens. xanthomonas citri subsp. citri is the bacterium responsible for citrus canker disease, which affects most citrus cultivars. the ability of this bacterium to coloni ...201324260514
the role of bacterial biofilms and surface components in plant-bacterial associations.the role of bacterial surface components in combination with bacterial functional signals in the process of biofilm formation has been increasingly studied in recent years. plants support a diverse array of bacteria on or in their roots, transport vessels, stems, and leaves. these plant-associated bacteria have important effects on plant health and productivity. biofilm formation on plants is associated with symbiotic and pathogenic responses, but how plants regulate such associations is unclear ...201323903045
transgenic sweet orange plants expressing a dermaseptin coding sequence show reduced symptoms of citrus canker disease.citrus canker provoked by xanthomonas axonopodis pv. citri is a bacterial disease causing severe losses in all citrus-producing areas around the world. xanthomonas infection is considered as an endemic disease in northeast and northwest argentina, affecting as much as 10% of commercial citrus plantations. there is not known natural resistance neither in orange varieties nor in rootstocks used for grafting of commercial cultivars. to introduce resistance to this disease, plants of pineapple sweet ...201323896218
identification and characterization of biofilm formation-defective mutants of xanthomonas citri subsp. citri.xanthomonas citri subsp. citri (xcc) develops a biofilm structure both in vitro and in vivo. despite all the progress achieved by studies regarding biofilm formation, many of its mechanisms remain poorly understood. this work focuses on the identification of new genes involved in biofilm formation and how they are related to motility, virulence and chemotaxis in xcc. a tn5 library of approximately 6000 xcc (strain 306) mutants was generated and screened to search for biofilm formation defective ...201323813675
increased resistance against citrus canker mediated by a citrus mitogen-activated protein kinase.mitogen-activated protein kinases (mapk) play crucial roles in plant immunity. we previously identified a citrus mapk (csmapk1) as a differentially expressed protein in response to infection by xanthomonas aurantifolii, a bacterium that causes citrus canker in mexican lime but a hypersensitive reaction in sweet oranges. here, we confirm that, in sweet orange, csmapk1 is rapidly and preferentially induced by x. aurantifolii relative to xanthomonas citri. to investigate the role of csmapk1 in citr ...201323777433
glutamate transport and xanthan gum production in the plant pathogen xanthomonas axonopodis pv. citri.l-glutamate plays a central role in nitrogen metabolism in all living organisms. in the genus xanthomonas, the nitrogen nutrition is an important factor involved in the xanthan gum production, an important exopolysaccharide with various industrial and biotechnological applications. in this report, we demonstrate that the use of l-glutamate by the phytopathogen xanthomonas axonopodis pv. citri as a nitrogen source in defined medium significantly increases the production of xanthan gum. this incre ...201323719672
structure of the pilz-fimxeal-c-di-gmp complex responsible for the regulation of bacterial type iv pilus biogenesis.signal transduction pathways mediated by cyclic-bis(3'→5')-dimeric gmp (c-di-gmp) control many important and complex behaviors in bacteria. c-di-gmp is synthesized through the action of ggdef domains that possess diguanylate cyclase activity and is degraded by eal or hd-gyp domains with phosphodiesterase activity. there is mounting evidence that some important c-di-gmp-mediated pathways require protein-protein interactions between members of the ggdef, eal, hd-gyp and pilz protein domain familie ...201323507310
variations in type iii effector repertoires, pathological phenotypes and host range of xanthomonas citri pv. citri pathotypes.the mechanisms determining the host range of xanthomonas are still undeciphered, despite much interest in their potential roles in the evolution and emergence of plant pathogenic bacteria. xanthomonas citri pv. citri (xci) is an interesting model of host specialization because of its pathogenic variants: pathotype a strains infect a wide range of rutaceous species, whereas pathotype a*/a(w) strains have a host range restricted to mexican lime (citrus aurantifolia) and alemow (citrus macrophylla) ...201323437976
characterization of a variant of xanthomonas citri subsp. citri that triggers a host-specific defense response.citrus is an economically important fruit crop that is severely afflicted by asiatic citrus bacterial canker (cbc), a disease caused by the phytopathogen xanthomonas citri subsp. citri (x. citri). to gain insight into the molecular epidemiology of cbc, 42 xanthomonas isolates were collected from a range of citrus spp. across 17 different orchards in tucumán, argentina and subjected to molecular, biochemical, and pathogenicity tests. analysis of genome-specific x. citri markers and dna polymorphi ...201323268580
evidence for acquisition of copper resistance genes from different sources in citrus-associated xanthomonads.abstract we determined that multiple and independent introductions of copper resistance genes have taken place for strains of xanthomonas citri subsp. citri from argentina and strains of x. alfalfae subsp. citrumelonis from florida. this study compared the partial nucleotide sequences of principal copper resistance genes copl, copa, and copb from x. citri subsp. citri and x. alfalfae subsp. citrumelonis to strains of other xanthomonas spp. resistant to copper that were isolated from 12 different ...201323252970
characterization of citrus sinensis transcription factors closely associated with the non-host response to xanthomonas campestris pv. vesicatoria.plants, when exposed to certain pathogens, may display a form of genotype-independent resistance, known as non-host response. in this study, the response of citrus sinensis (sweet orange) leaves to xanthomonas campestris pv. vesicatoria (xcv), a pepper and tomato pathogenic bacterium, was analyzed through biochemical assays and cdna microarray hybridization and compared with asiatic citrus canker infection caused by xanthomonas citri subsp. citri. citrus leaves exposed to the non-host bacterium ...201323453188
host immune responses accelerate pathogen evolution.pathogens face a hostile and often novel environment when infecting a new host, and adaptation is likely to be an important determinant of the success in colonization and establishment. we hypothesized that resistant hosts will impose stronger selection on pathogens than susceptible hosts, which should accelerate pathogen evolution through selection biased toward effector genes. to test this hypothesis, we conducted an experimental evolution study on xanthomonas citri subsp. citri (xcc) in a sus ...201324304673
host immune responses accelerate pathogen evolution.pathogens face a hostile and often novel environment when infecting a new host, and adaptation is likely to be an important determinant of the success in colonization and establishment. we hypothesized that resistant hosts will impose stronger selection on pathogens than susceptible hosts, which should accelerate pathogen evolution through selection biased toward effector genes. to test this hypothesis, we conducted an experimental evolution study on xanthomonas citri subsp. citri (xcc) in a sus ...201324304673
high-quality draft genome sequences of two xanthomonas citri pv. malvacearum strains.we report high-quality draft genome sequences of two strains (race 18 and 20) of xanthomonas citri pv. malvacearum, the causal agent of bacterial blight of cotton. comparative genomics will help to decipher mechanisms provoking disease and triggering defense responses and to develop new molecular tools for epidemiological surveillance.201323990578
comparative genomic and transcriptome analyses of pathotypes of xanthomonas citri subsp. citri provide insights into mechanisms of bacterial virulence and host range.citrus bacterial canker is a disease that has severe economic impact on citrus industries worldwide and is caused by a few species and pathotypes of xanthomonas. x. citri subsp. citri strain 306 (xcca306) is a type a (asiatic) strain with a wide host range, whereas its variant x. citri subsp. citri strain a(w)12879 (xcaw12879, wellington strain) is restricted to mexican lime.201323941402
citrus maf1, a repressor of rna polymerase iii, binds the xanthomonas citri canker elicitor ptha4 and suppresses citrus canker development.transcription activator-like (tal) effectors from xanthomonas species pathogens act as transcription factors in plant cells; however, how tal effectors activate host transcription is unknown. we found previously that tal effectors of the citrus canker pathogen xanthomonas citri, known as pthas, bind the carboxyl-terminal domain of the sweet orange (citrus sinensis) rna polymerase ii (pol ii) and inhibit the activity of cscyp, a cyclophilin associated with the carboxyl-terminal domain of the citr ...201323898043
antibacterial activity of extracellular compounds produced by a pseudomonas strain against methicillin-resistant staphylococcus aureus (mrsa) strains.the emergence of multidrug-resistant bacteria is a world health problem. staphylococcus aureus, including methicillin-resistant s. aureus (mrsa) strains, is one of the most important human pathogens associated with hospital and community-acquired infections. the aim of this work was to evaluate the antibacterial activity of a pseudomonas aeruginosa-derived compound against mrsa strains.201323773484
a redox 2-cys mechanism regulates the catalytic activity of divergent cyclophilins.the citrus (citrus sinensis) cyclophilin cscyp is a target of the xanthomonas citri transcription activator-like effector ptha, required to elicit cankers on citrus. cscyp binds the citrus thioredoxin cstdx and the carboxyl-terminal domain of rna polymerase ii and is a divergent cyclophilin that carries the additional loop ksgkplh, invariable cysteine (cys) residues cys-40 and cys-168, and the conserved glutamate (glu) glu-83. despite the suggested roles in atp and metal binding, the functions o ...201323709667
complete genome sequence of xanthomonas citri subsp. citri strain aw12879, a restricted-host-range citrus canker-causing bacterium.xanthomonas citri subsp. citri causes citrus canker. the asiatic strain has a broad host range, whereas the wellington variant has a restricted host range. here, we present the complete genome of x. citri subsp. citri strain a(w)12879. this study lays the foundation to further characterize the mechanisms for virulence and host range of x. citri.201323682143
antibacterial activity of alkyl gallates against xanthomonas citri subsp. citri.the plant-pathogenic bacterium xanthomonas citri subsp. citri is the causal agent of asiatic citrus canker, a serious disease that affects all the cultivars of citrus in subtropical citrus-producing areas worldwide. there is no curative treatment for citrus canker; thus, the eradication of infected plants constitutes the only effective control of the spread of x. citri subsp. citri. since the eradication program in the state of são paulo, brazil, is under threat, there is a clear risk of x. citr ...201323104804
requirement of the lipopolysaccharide o-chain biosynthesis gene wxocb for type iii secretion and virulence of xanthomonas oryzae pv. oryzicola.xanthomonas oryzae pv. oryzicola causes bacterial leaf streak of rice. a mutant disrupted in wxocb, predicted to encode an enzyme for lipopolysaccharide (lps) synthesis, was previously shown to suffer reduced virulence. here, we confirm a role for wxocb in virulence and demonstrate its requirement for lps o-chain assembly. structure analysis indicated that wild-type lps contains a polyrhamnose o chain with irregular, variant residues and a core oligosaccharide identical to that of other xanthomo ...201323435979
high-resolution transcriptional analysis of the regulatory influence of cell-to-cell signalling reveals novel genes that contribute to xanthomonas phytopathogenesis.the bacterium xanthomonas campestris is an economically important pathogen of many crop species and a model for the study of bacterial phytopathogenesis. in x. campestris, a regulatory system mediated by the signal molecule dsf controls virulence to plants. the synthesis and recognition of the dsf signal depends upon different rpf proteins. dsf signal generation requires rpff whereas signal perception and transduction depends upon a system comprising the sensor rpfc and regulator rpfg. here we h ...201323617851
prophage-mediated dynamics of 'candidatus liberibacter asiaticus' populations, the destructive bacterial pathogens of citrus huanglongbing.prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. there are at least two prophages in the chromosomes of candidatus liberibacter asiaticus' (las) floridian isolates. las is both unculturable and the most prevalent species of liberibacter pathogens that cause huanglongbing (hlb), a worldwide destructive disease of citrus. in this study, seven new prophage variants resulting from two hyper-variable regions were identified by scre ...201324349235
genomic survey of pathogenicity determinants and vntr markers in the cassava bacterial pathogen xanthomonas axonopodis pv. manihotis strain cio151.xanthomonas axonopodis pv. manihotis (xam) is the causal agent of bacterial blight of cassava, which is among the main components of human diet in africa and south america. current information about the molecular pathogenicity factors involved in the infection process of this organism is limited. previous studies in other bacteria in this genus suggest that advanced draft genome sequences are valuable resources for molecular studies on their interaction with plants and could provide valuable too ...201324278159
multilocus variable-number-tandem-repeats analysis (mlva) distinguishes a clonal complex of clavibacter michiganensis subsp. michiganensis strains isolated from recent outbreaks of bacterial wilt and canker in belgium.clavibacter michiganensis subsp. michiganensis (cmm) causes bacterial wilt and canker in tomato. cmm is present nearly in all european countries. during the last three years several local outbreaks were detected in belgium. the lack of a convenient high-resolution strain-typing method has hampered the study of the routes of transmission of cmm and epidemiology in tomato cultivation. in this study the genetic relatedness among a worldwide collection of cmm strains and their relatives was approach ...201323738754
candidatus liberibacter americanus induces significant reprogramming of the transcriptome of the susceptible citrus genotype.citrus huanglongbing (hlb) disease is caused by endogenous, phloem-restricted, gram negative, uncultured bacteria named candidatus liberibacter africanus (calaf), ca. l. asiaticus (calas), and ca. l. americanus (calam), depending on the continent where the bacteria were first detected. the asian citrus psyllid vector, diaphorina citri, transmits calas and calam and both liberibacter species are present in brazil. several studies of the transcriptional response of citrus plants manifesting hlb sy ...201323586643
crystal structure of the fad-containing ferredoxin-nadp+ reductase from the plant pathogen xanthomonas axonopodis pv. citri.we have solved the structure of ferredoxin-nadp(h) reductase, fpr, from the plant pathogen xanthomonas axonopodis pv. citri, responsible for citrus canker, at a resolution of 1.5 å. this structure reveals differences in the mobility of specific loops when compared to other fprs, probably unrelated to the hydride transfer process, which contributes to explaining the structural and functional divergence between the subclass i fprs. interactions of the c-terminus of the enzyme with the phosphoadeno ...201323984418
a specific interdomain interaction preserves the structural and binding properties of the moda protein from the phytopathogen xanthomonas citri domain interaction and transport in moda.the periplasmic-binding proteins in atp-binding cassette systems (abc transporters) are responsible for the capture and delivery of ligands to their specific transporters, triggering a series of atp-driven conformational changes that leads to the transport of the ligand. structurally consisting of two lobes, the proteins change conformation after interaction with the ligand. the structure of the molybdate-binding protein (moda) from xanthomonas citri, bound to molybdate, was previously solved by ...201324035743
a csra/rsma translational regulator gene encoded in the replication region of a sinorhizobium meliloti cryptic plasmid complements pseudomonas fluorescens rsma/e mutants.members of the csra/rsma family are global regulatory proteins that bind to mrnas, usually at the ribosome-binding site, to control mrna translation and stability. their activity is counteracted by small non-coding rnas (srnas), which offer several binding sites to compete with mrna binding. the csra/rsma genes are widespread in prokaryotic chromosomes, although certain phylogenetic groups such as alphaproteobacteria lack this type of global regulator. interestingly, a csra/rsma-like sequence wa ...201323175505
analysis of three xanthomonas axonopodis pv. citri effector proteins in pathogenicity and their interactions with host plant proteins.xanthomonas axonopodis pv. citri, the bacterium responsible for citrus canker, uses effector proteins secreted by a type iii protein secretion system to colonize its hosts. among the putative effector proteins identified for this bacterium, we focused on the analysis of the roles of avrxace1, avrxace2 and xac3090 in pathogenicity and their interactions with host plant proteins. bacterial deletion mutants in avrxace1, avrxace2 and xac3090 were constructed and evaluated in pathogenicity assays. th ...201222435635
proteomic characterization of the rph15 barley resistance gene-mediated defence responses to leaf rust.leaf rust, caused by the biotrophic fungal pathogen puccinia hordei, is one of the most important foliar disease of barley (hordeum vulgare) and represents a serious threat in many production regions of the world. the leaf rust resistance gene rph15 is of outstanding interest for resistance breeding because it confers resistance to over 350 puccinia hordei isolates collected from around the world. molecular and biochemical mechanisms responsible for the rph15 effectiveness are currently not inve ...201223167439
rna-seq and microarray complement each other in transcriptome profiling.rna-seq and microarray are the two popular methods employed for genome-wide transcriptome profiling. current comparison studies have shown that transcriptome quantified by these two methods correlated well. however, none of them have addressed if they complement each other, considering the strengths and the limitations inherent with them. the pivotal requirement to address this question is the knowledge of a well known data set. in this regard, hrpx regulome from pathogenic bacteria serves as an ...201223153100
different transcriptional response to xanthomonas citri subsp. citri between kumquat and sweet orange with contrasting canker tolerance.citrus canker disease caused by xanthomonas citri subsp. citri (xcc) is one of the most devastating biotic stresses affecting the citrus industry. meiwa kumquat (fortunella crassifolia) is canker-resistant, while newhall navel orange (citrus sinensis osbeck) is canker-sensitive. to understand the molecular mechanisms underlying the differences in responses to xcc, transcriptomic profiles of these two genotypes following xcc attack were compared by using the affymetrix citrus genome genechip. a t ...201222848606
tal effectors target the c-terminal domain of rna polymerase ii (ctd) by inhibiting the prolyl-isomerase activity of a ctd-associated cyclophilin.transcriptional activator-like (tal) effectors of plant pathogenic bacteria function as transcription factors in plant cells. however, how tal effectors control transcription in the host is presently unknown. previously, we showed that tal effectors of the citrus canker pathogen xanthomonas citri, named pthas, targeted the citrus protein complex comprising the thioredoxin cstdx, ubiquitin-conjugating enzymes csuev/ubc13 and cyclophilin cscyp. here we show that cscyp complements the function of c ...201222911812
genome sequence of xanthomonas citri pv. mangiferaeindicae strain lmg 941.we report the 5.1-mb genome sequence of xanthomonas citri pv. mangiferaeindicae strain lmg 941, the causal agent of bacterial black spot in mango. apart from evolutionary studies, the draft genome will be a valuable resource for the epidemiological studies and quarantine of this phytopathogen.201222582385
the tal effector ptha4 interacts with nuclear factors involved in rna-dependent processes including a hmg protein that selectively binds poly(u) rna.plant pathogenic bacteria utilize an array of effector proteins to cause disease. among them, transcriptional activator-like (tal) effectors are unusual in the sense that they modulate transcription in the host. although target genes and dna specificity of tal effectors have been elucidated, how tal proteins control host transcription is poorly understood. previously, we showed that the xanthomonas citri tal effectors, pthas 2 and 3, preferentially targeted a citrus protein complex associated wi ...201222384209
functional divergence of fimx in pilz binding and type iv pilus regulation.type iv pili (t4p) are polar surface structures that play important roles in bacterial motility, biofilm formation, and pathogenicity. the protein fimx and its orthologs are known to mediate t4p formation in the human pathogen pseudomonas aeruginosa and some other bacterial species. it was reported recently that fimx(xac2398) from xanthomonas axonopodis pv. citri interacts with pilz(xac1133) directly through the nonenzymatic eal domain of fimx(xac2398). here we present experimental data to revea ...201222942245
genomes-based phylogeny of the genus xanthomonas.the genus xanthomonas comprises several plant pathogenic bacteria affecting a wide range of hosts. despite the economic, industrial and biological importance of xanthomonas, the classification and phylogenetic relationships within the genus are still under active debate. some of the relationships between pathovars and species have not been thoroughly clarified, with old pathovars becoming new species. a change in the genus name has been recently suggested for xanthomonas albilineans, an early br ...201222443110
improved thermostability of aeh by combining b-fit analysis and structure-guided consensus method.α-amino ester hydrolases (aeh, e.c. 3.1.1.43) catalyze the synthesis and hydrolysis of α-amino β-lactam antibiotics. the aeh enzymes have been shown to feature excellent synthetic capability but suffer from poor thermostability. aeh from xanthomonas campestris exhibits an optimal activity temperature of 25 °c, an observed half-life of 5 min at 30 °c, and a "t-50" value, the temperature at which the half-life is 30 min, of 27 °c. to improve the thermostability of aeh, a modified structure-guided ...201222426092
recombinant expression and characterization of a cysteine peptidase from xanthomonas citri subsp citri.xanthomonas citri subsp citri (xac) is the bacterium responsible for citrus canker disease in citrus plants. the aim of this study was to describe the recombinant expression, purification, and characterization of a cysteine peptidase from xac strain 306, which is a candidate for involvement in the pathogenicity of this bacterium. the gene was cloned and expressed in pichia pastoris, and the cysteine peptidase was successfully expressed, secreted, and purified using affinity chromatography with a ...201223212341
pathogen-induced accumulation of an ellagitannin elicits plant defense response.in an incompatible interaction between colletotrichum fragariae and strawberry plants, the accumulation of phenolic compounds in plant leaves was observed. a particularly abundant penta-esterified ellagitannin that accumulated in response to pathogen attack was identified as 1-0-galloyl-2,3;4,6-bis-hexahydroxydiphenoyl-β-d-glucopyranose (het) by mass spectroscopy and nuclear magnetic resonance. foliar application of purified het prior to inoculation with a virulent pathogen was shown to increase ...201222934564
contribution of a harpin protein from xanthomonas axonopodis pv. citri to pathogen virulence.xanthomonas axonopodis pv. citri (xac), the bacterium that causes citrus canker, contains a gene in the hrp [for hypersensitive response (hr) and pathogenicity] cluster that encodes a harpin protein called hpa1. hpa1 produced hr in the nonhost plants tobacco, pepper and arabidopsis, whereas, in the host plant citrus, it elicited a weak defence response with no visible phenotype. co-infiltrations of xac with or without the recombinant hpa1 protein in citrus leaves produced a larger number of cank ...201222788999
the structure of a xanthomonas general stress protein involved in citrus canker reveals its flavin-binding property.xanthomonas citri pv. citri (xac) causes citrus canker and affects citrus agriculture worldwide. functional genetic analysis has indicated that a putative general stress protein (xacgsp) encoded by the xac2369 gene is involved in the bacterial infection. in this report, the crystal structure of xacgsp was determined to 2.5 å resolution. there are four xacgsp molecules in the crystal asymmetric unit. each xacgsp monomer folds into a six-stranded antiparallel β-barrel flanked by five α-helices. a ...201222751670
hrpm is involved in glucan biosynthesis, biofilm formation and pathogenicity in xanthomonas citri ssp. citri.xanthomonas citri ssp. citri (xcc) is the causal agent of citrus canker. this bacterium develops a characteristic biofilm on both biotic and abiotic surfaces. a biofilm-deficient mutant was identified in a screening of a transposon mutagenesis library of the xcc 306 strain constructed using the commercial tn5 transposon ez-tn5 <kan-2> tnp transposome (epicentre). sequence analysis of a mutant obtained in the screening revealed that a single copy of the ez-tn5 was inserted at position 446 of hrpm ...201222738424
construction of egfp-labeling system for visualizing the infection process of xanthomonas axonopodis pv. citri in planta.xanthomonas axonopodis pv. citri (xac) is the causal agent of citrus bacterial canker, an economically important disease to world citrus industry. to monitor the infection process of xac in different citrus plants, the enhanced green florescent protein (egfp) visualizing system was constructed to visualize the propagation and localization in planta. first, the wild-type xac was isolated from the diseased leaves of susceptible 'bingtang' sweet orange, and then the isolated xac was labeled with eg ...201222674174
exogenous treatment with salicylic acid attenuates occurrence of citrus canker in susceptible navel orange (citrus sinensis osbeck).citrus canker caused by xanthomonas axonopodis pv. citri (xac) is a devastating bacterial disease threatening the citrus industry. salicylic acid (sa) plays a key role in plant defense response to biotic stress, but information is scarce concerning the application of sa to enhancing xac resistance. in the present research attempts were made to investigate how exogenous application of sa influenced canker disease outbreak in navel orange (citrus sinensis). exogenously applied sa at 0.25 mm signif ...201222658220
the novel virulence-related gene nlxa in the lipopolysaccharide cluster of xanthomonas citri ssp. citri is involved in the production of lipopolysaccharide and extracellular polysaccharide, motility, biofilm formation and stress resistance.lipopolysaccharide (lps) is an important virulence factor of xanthomonas citri ssp. citri, the causative agent of citrus canker disease. in this research, a novel gene, designated as nlxa (novel lps cluster gene of x. citri ssp. citri), in the lps cluster of x. citri ssp. citri 306, was characterized. our results indicate that nlxa is required for o-polysaccharide biosynthesis by encoding a putative rhamnosyltransferase. this is supported by several lines of evidence: (i) nlxa shares 40.14% iden ...201222458688
crystal structure of the campylobacter jejuni cj0090 protein reveals a novel variant of the immunoglobulin fold among bacterial lipoproteins.bacterial lipoproteins play an important role in bacterial pathogenesis and physiology. the genome of campylobacter jejuni, a major foodborn pathogen, is predicted to contain over 20 lipoproteins. however, the functions of the majority of c. jejuni lipoproteins remain unknown. the cj0090 protein is encoded by a lipoprotein operon composed of cj0089, cj0090, and cj0091. here, we report the crystal structure of cj0090 at 1.9 å resolution, revealing a novel variant of the immunoglobulin fold with β ...201222987763
reactive oxygen species in the signaling and adaptation of multicellular microbial communities.one of the universal traits of microorganisms is their ability to form multicellular structures, the cells of which differentiate and communicate via various signaling molecules. reactive oxygen species (ros), and hydrogen peroxide in particular, have recently become well-established signaling molecules in higher eukaryotes, but still little is known about the regulatory functions of ros in microbial structures. here we summarize current knowledge on the possible roles of ros during the developm ...201222829965
surface organelles assembled by secretion systems of gram-negative bacteria: diversity in structure and function.gram-negative bacteria express a wide variety of organelles on their cell surface. these surface structures may be the end products of secretion systems, such as the hair-like fibers assembled by the chaperone/usher (cu) and type iv pilus pathways, which generally function in adhesion to surfaces and bacterial-bacterial and bacterial-host interactions. alternatively, the surface organelles may be integral components of the secretion machinery itself, such as the needle complex and pilus extensio ...201222545799
a lov protein modulates the physiological attributes of xanthomonas axonopodis pv. citri relevant for host plant colonization.recent studies have demonstrated that an appropriate light environment is required for the establishment of efficient vegetal resistance responses in several plant-pathogen interactions. the photoreceptors implicated in such responses are mainly those belonging to the phytochrome family. data obtained from bacterial genome sequences revealed the presence of photosensory proteins of the bluf (blue light sensing using fad), lov (light, oxygen, voltage) and phytochrome families with no known functi ...201222675525
dna polymorphisms and biocontrol of bacillus antagonistic to citrus bacterial canker with indication of the interference of phyllosphere biofilms.citrus bacterial canker caused by xanthomonas axonopodis pv. citri is a devastating disease resulting in significant crop losses in various citrus cultivars worldwide. a biocontrol agent has not been recommended for this disease. to explore the potential of bacilli native to taiwan to control this disease, bacillus species with a broad spectrum of antagonistic activity against various phytopathogens were isolated from plant potting mixes, organic compost and the rhizosphere soil. seven strains t ...201222848728
a conjugative 38 kb plasmid is present in multiple subspecies of xylella fastidiosa.a ≈ 38kb plasmid (pxf-riv5) was present in the riv5 strain of xylella fastidiosa subsp. multiplex isolated from ornamental plum in southern california. the complete nucleotide sequence of pxf-riv5 is almost identical to that of pxfas01 from x. fastidiosa subsp. fastidiosa strain m23; the two plasmids vary at only 6 nucleotide positions. blast searches and phylogenetic analyses indicate pxf-riv5 and pxfas01 share some similarity to chromosomal and plasmid (pxf51) sequences of x. fastidiosa subsp. ...201223251694
genetic and functional characterization of cyclic lipopeptide white-line-inducing principle (wlip) production by rice rhizosphere isolate pseudomonas putida rw10s2.the secondary metabolite mediating the gacs-dependent growth-inhibitory effect exerted by the rice rhizosphere isolate pseudomonas putida rw10s2 on phytopathogenic xanthomonas species was identified as white-line-inducing principle (wlip), a member of the viscosin group of cyclic lipononadepsipeptides. wlip producers are commonly referred to by the taxonomically invalid name "pseudomonas reactans," based on their capacity to reveal the presence of a nearby colony of pseudomonas tolaasii by induc ...201222544260
advances in bacteriophage-mediated control of plant pathogens.there is continuing pressure to maximise food production given a growing global human population. bacterial pathogens that infect important agricultural plants (phytopathogens) can reduce plant growth and the subsequent crop yield. currently, phytopathogens are controlled through management programmes, which can include the application of antibiotics and copper sprays. however, the emergence of resistant bacteria and the desire to reduce usage of toxic products that accumulate in the environment ...201222934116
modifications of xanthomonas axonopodis pv. citri lipopolysaccharide affect the basal response and the virulence process during citrus canker.xanthomonas axonopodis pv. citri (xac) is the phytopathogen responsible for citrus canker, one of the most devastating citrus diseases in the world. a broad range of pathogens is recognized by plants through so-called pathogen-associated molecular patterns (pamps), which are highly conserved fragments of pathogenic molecules. in plant pathogenic bacteria, lipopolisaccharyde (lps) is considered a virulence factor and it is being recognized as a pamp. the study of the participation of xac lps in c ...201222792211
catecholate siderophores protect bacteria from pyochelin toxicity.bacteria produce small molecule iron chelators, known as siderophores, to facilitate the acquisition of iron from the environment. the synthesis of more than one siderophore and the production of multiple siderophore uptake systems by a single bacterial species are common place. the selective advantages conferred by the multiplicity of siderophore synthesis remains poorly understood. however, there is growing evidence suggesting that siderophores may have other physiological roles besides their ...201223071628
the destructive citrus pathogen, 'candidatus liberibacter asiaticus' encodes a functional flagellin characteristic of a pathogen-associated molecular pattern.huanglongbing (hlb) is presently the most devastating citrus disease worldwide. as an intracellular plant pathogen and insect symbiont, the hlb bacterium, 'candidatus liberibacter asiaticus' (las), retains the entire flagellum-encoding gene cluster in its significantly reduced genome. las encodes a flagellin and hook-associated protein (fla) of 452 amino acids that contains a conserved 22 amino acid domain (flg22) at positions 29 to 50 in the n-terminus. the phenotypic alteration in motility of ...201223029520
the plant cell wall: a dynamic barrier against pathogen invasion.prospective plant pathogens must overcome the physical barrier presented by the plant cell wall. in addition to being a preformed, passive barrier limiting access of pathogens to plant cells, the cell wall is actively remodeled and reinforced specifically at discrete sites of interaction with potentially pathogenic microbes. active reinforcement of the cell wall through the deposition of cell wall appositions, referred to as papillae, is an early response to perception of numerous categories of ...201222639669
xylella fastidiosa comparative genomic database is an information resource to explore the annotation, genomic features, and biology of different strains.the xylella fastidiosa comparative genomic database is a scientific resource with the aim to provide a user-friendly interface for accessing high-quality manually curated genomic annotation and comparative sequence analysis, as well as for identifying and mapping prophage-like elements, a marked feature of xylella genomes. here we describe a database and tools for exploring the biology of this important plant pathogen. the hallmarks of this database are the high quality genomic annotation, the f ...201222481888
non-host defense response in a novel arabidopsis-xanthomonas citri subsp. citri pathosystem.citrus canker, caused by xanthomonas citri subsp. citri (xcc), is one of the most destructive diseases of citrus. progress of breeding citrus canker-resistant varieties is modest due to limited resistant germplasm resources and lack of candidate genes for genetic manipulation. the objective of this study is to establish a novel heterologous pathosystem between xcc and the well-established model plant arabidopsis thaliana for defense mechanism dissection and resistance gene identification. our re ...201222299054
the gpsx gene encoding a glycosyltransferase is important for polysaccharide production and required for full virulence in xanthomonas citri subsp. citri.the gram-negative bacterium xanthomonas citri subsp. citri (xac) causes citrus canker, one of the most destructive diseases of citrus worldwide. in our previous work, a transposon mutant of xac strain 306 with an insertion in the xac3110 locus was isolated in a screening that aimed at identifying genes related to biofilm formation. the xac3110 locus was named as bdp24 for biofilm-defective phenotype and the mutant was observed to be affected in extracellular polysaccharide (eps) and lipopolysacc ...201222404966
High-Throughput Screening and Analysis of Genes of Xanthomonas citri subsp. citri Involved in Citrus Canker Symptom Development.Citrus canker is caused by Xanthomonas citri subsp. citri and is one of the most devastating diseases on citrus plants. To investigate the virulence mechanism of this pathogen, a mutant library of strain 306 containing approximately 22,000 mutants was screened for virulence-deficient mutants in grapefruit (Citrus paradise). Eighty-two genes were identified that contribute to citrus canker symptom development caused by X. citri subsp. citri. Among the 82 identified genes, 23 genes were classified ...201221899385
Characterization of Streptomyces padanus JAU4234, a Producer of Actinomycin X2, Fungichromin, and a New Polyene Macrolide Antibiotic.Strain JAU4234, identified as Streptomyces padanus, was isolated from soil collected in Jiangxi Province, China. It produced actinomycin X2, fungichromin, and a new polyene macrolide compound with antifungal activity, antifungalmycin 702. Antifungalmycin 702 had good general antifungal activity and may have potential future agricultural and/or clinical applications.201222057866
plant lectin-like antibacterial proteins from phytopathogens pseudomonas syringae and xanthomonas citri.the genomes of pseudomonas syringae pv. syringae 642 and xanthomonas citri pv. malvacearum lmg 761 each carry a putative homologue of the plant lectin-like bacteriocin (llpa) genes previously identified in the rhizosphere isolate pseudomonas putida bw11m1 and the biocontrol strain pseudomonas fluorescens pf-5. the respective purified recombinant proteins, llpapss642 and llpaxcm761 , display genus-specific antibacterial activity across species boundaries. the inhibitory spectrum of the p. syringa ...201223760822
qcm immunoassay for recombinant cysteine peptidase: a potential protein biomarker for diagnosis of citrus canker.citrus canker is one of the most important agricultural citrus diseases worldwide. it is caused by xanthomonas citri subsp. citri (xcc) bacterium that infects leaves and the fruits produce a cysteine peptidase (cpxac), which makes it a potential target for the development of effective and rapid detection methods for citrus canker. we report here the studies on the development of piezoelectric immunoassay for cpxac using a polyclonal antibody against cpxac (anti-cpxac). three different strategies ...201223597909
transcriptional profiling of canker-resistant transgenic sweet orange (citrus sinensis osbeck) constitutively overexpressing a spermidine synthase gene.citrus canker disease caused by xanthomonas citri subsp. citri (xcc) is one of the most devastating diseases affecting the citrus industry worldwide. in our previous study, the canker-resistant transgenic sweet orange (citrus sinensis osbeck) plants were produced via constitutively overexpressing a spermidine synthase. to unravel the molecular mechanisms underlying xcc resistance of the transgenic plants, in the present study global transcriptional profiling was compared between untransformed li ...201223509803
considerations for using bacteriophages for plant disease control.the use of bacteriophages as an effective phage therapy strategy faces significant challenges for controlling plant diseases in the phyllosphere. a number of factors must be taken into account when considering phage therapy for bacterial plant pathogens. given that effective mitigation requires high populations of phage be present in close proximity to the pathogen at critical times in the disease cycle, the single biggest impediment that affects the efficacy of bacteriophages is their inability ...201223531902
First report of a bifunctional chitinase/lysozyme produced by Bacillus pumilus SG2.Bacillus pumilus SG2 isolated from high salinity ecosystem in Iran produces two chitinases (ChiS and ChiL) and secretes them into the medium. In this study, chiS and chiL genes were cloned in pQE-30 expression vector and were expressed in the cytoplasm of Escherichia coli strain M15. The recombinant proteins were purified using Ni-NTA column. The optimum pH and optimum temperature for enzyme activity of ChiS were pH 6, 50°C; those of ChiL were pH 6.5, 40°C. The purified chitinases showed antifun ...201122112904
Structural-functional characterization and physiological significance of ferredoxin-NADP reductase from Xanthomonas axonopodis pv. citri.Xanthomonas axonopodis pv. citri is a phytopathogen bacterium that causes severe citrus canker disease. Similar to other phytopathogens, after infection by this bacterium, plants trigger a defense mechanism that produces reactive oxygen species. Ferredoxin-NADP(+) reductases (FNRs) are redox flavoenzymes that participate in several metabolic functions, including the response to reactive oxygen species. Xanthomonas axonopodis pv. citri has a gene (fpr) that encodes for a FNR (Xac-FNR) that belong ...201122096528
Comparative genomic analysis of Xanthomonas axonopodis pv. citrumelo F1, which causes citrus bacterial spot disease, and related strains provides insights into virulence and host specificity.Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campest ...201121908674
a component of the xanthomonadaceae type iv secretion system combines a virb7 motif with a n0 domain found in outer membrane transport proteins.type iv secretion systems (t4ss) are used by gram-negative bacteria to translocate protein and dna substrates across the cell envelope and into target cells. translocation across the outer membrane is achieved via a ringed tetradecameric outer membrane complex made up of a small virb7 lipoprotein (normally 30 to 45 residues in the mature form) and the c-terminal domains of the virb9 and virb10 subunits. several species from the genera of xanthomonas phytopathogens possess an uncharacterized type ...201121589901
structural analysis and involvement in plant innate immunity of xanthomonas axonopodis pv. citri lipopolysaccharide.xanthomonas axonopodis pv. citri causes citrus canker, provoking defoliation and premature fruit drop with the concomitant economical damage. in plant pathogenic bacteria, lipopolysaccharides are important virulence factors and they are being increasingly recognized as major pathogen associated molecular patterns for plants. in general three domains are recognized in a lipopolysaccharide: the hydrophobic lipid a, the hydrophilic o-antigen polysaccharide and the core oligosaccharide, connecting l ...201121596742
structural insights on two hypothetical secretion chaperones from xanthomonas axonopodis pv. citri.several gram-negative bacterial pathogens have developed type iii secretion systems (t3sss) to deliver virulence proteins directly into eukaryotic cells in a process essential for many diseases. the type iii secretion processes require customized chaperones with high specificity for binding partners, thus providing the secretion to occur. due to the very low sequence similarities among secretion chaperones, annotation and discrimination of a great majority of them is extremely difficult and a ta ...201121626158
the colr/cols two-component system plays multiple roles in the pathogenicity of the citrus canker pathogen xanthomonas citri subsp. citri.bacterial citrus canker disease, which is caused by xanthomonas citri subsp. citri, is one of the most devastating diseases of citrus plants. in this study, we characterized the role of the two-component regulatory system colr/cols in the pathogenicity of x. citri subsp. citri. cols mutants (256a10 and 421e7), colr mutants (386c6 and 417e10), and a colr cols double mutant (306dsr) all lost pathogenicity and produced no symptoms on grapefruit leaves inoculated by either pressure infiltration or t ...201121257774
hrpg and hrpx play global roles in coordinating different virulence traits of xanthomonas axonopodis pv. citri.xanthomonas axonopodis pv. citri is the causal agent of citrus canker, which is one of the most serious diseases of citrus. to understand the virulence mechanisms of x. axonopodis pv. citri, we designed and conducted genome-wide microarray analyses to characterize the hrpg and hrpx regulons, which are critical for the pathogenicity of x. axonopodis pv. citri. our analyses revealed that 232 and 181 genes belonged to the hrpg and hrpx regulons, respectively. in total, 123 genes were overlapped in ...201121261465
selection and validation of reference genes for gene expression studies by reverse transcription quantitative pcr in xanthomonas citri subsp. citri during infection of citrus sinensis.xanthomonas citri subsp. citri (xcc) causes citrus canker, a worldwide disease found mainly in sweet oranges (citrus sinensis (l.) osbeck). the expression of nine candidate internal reference genes was analyzed in xcc grown alone and during c. sinensis infection to identify genes most suitable for comparative expression studies in xcc using reverse transcription quantitative pcr (qrt-pcr). the stability of these genes was determined using the programs genorm, normfinder and bestkeeper. the genes ...201121318633
insertion sequence- and tandem repeat-based genotyping techniques for xanthomonas citri pv. mangiferaeindicae.molecular fingerprinting techniques that have the potential to identify or subtype bacteria at the strain level are needed for improving diagnosis and understanding of the epidemiology of pathogens such as xanthomonas citri pv. mangiferaeindicae, which causes mango bacterial canker disease. we developed a ligation-mediated polymerase chain reaction targeting the is1595 insertion sequence as a means to differentiate pv. mangiferaeindicae from the closely related pv. anacardii (responsible for cas ...201121323466
comparative genomics reveals diversity among xanthomonads infecting tomato and pepper.bacterial spot of tomato and pepper is caused by four xanthomonas species and is a major plant disease in warm humid climates. the four species are distinct from each other based on physiological and molecular characteristics. the genome sequence of strain 85-10, a member of one of the species, xanthomonas euvesicatoria (xcv) has been previously reported. to determine the relationship of the four species at the genome level and to investigate the molecular basis of their virulence and differing ...201121396108
structure-function analysis of the hrpb2-hrcu interaction in the xanthomonas citri type iii secretion system.bacterial type iii secretion systems deliver protein virulence factors to host cells. here we characterize the interaction between hrpb2, a small protein secreted by the xanthomonas citri subsp. citri type iii secretion system, and the cytosolic domain of the inner membrane protein hrcu, a paralog of the flagellar protein flhb. we show that a recombinant fragment corresponding to the c-terminal cytosolic domain of hrcu produced in e. coli suffers cleavage within a conserved asn264-pro265-thr266- ...201121408079
agrobacterium-mediated transient expression in citrus leaves: a rapid tool for gene expression and functional gene assay.in this study, we present a method for transient expression of the type iii effector avrgf1 from xanthomonas citri subsp. citri strain a(w) in grapefruit leaves (citrus paradisi) via agrobacterium tumefaciens. the coding sequence of avrgf1 was placed under the control of the constitutive camv 35s promoter in the binary vectors pgwb2 and pgwb5. infiltration of grapefruit leaves with a. tumefaciens carrying these constructs triggered a hypersensitive response (hr) in grapefruit 4 days after inocul ...201121424250
ectopic expression of mdspds1 in sweet orange (citrus sinensis osbeck) reduces canker susceptibility: involvement of hôééoôéé production and transcriptional alteration.enormous work has shown that polyamines are involved in a variety of physiological processes, but information is scarce on the potential of modifying disease response through genetic transformation of a polyamine biosynthetic gene.201121439092
the wxaco gene of xanthomonas citri ssp. citri encodes a protein with a role in lipopolysaccharide biosynthesis, biofilm formation, stress tolerance and virulence.xanthomonas citri ssp. citri (xcc) causes citrus canker, one of the most economically damaging diseases affecting citrus worldwide. biofilm formation is important for the pathogen to survive epiphytically in planta prior to the induction of canker symptoms. in this study, two ez-tn5 transposon mutants of xcc strain 306, affected in biofilm formation, were isolated; subsequent analyses led to the identification of a novel gene locus xac3596 (designated as wxaco), encoding a putative transmembrane ...201121453433
molecular characterization of copper resistance genes from xanthomonas citri subsp. citri and xanthomonas alfalfae subsp. citrumelonis.copper sprays have been widely used for control of endemic citrus canker caused by xanthomonas citri subsp. citri (xcc) in citrus-growing areas for more than two decades. xanthomonas alfalfae subsp. citrumelonis (xac) populations were also exposed to frequent sprays of copper for several years as a protective measure against citrus bacterial spot (cbs) in florida citrus nurseries. long term use of these bactericides has led to the development of copper resistant (cu(r)) strains in both xcc and x ...201121515725
terpene down-regulation in orange reveals the role of fruit aromas in mediating interactions with insect herbivores and pathogens.plants use volatile terpene compounds as odor cues for communicating with the environment. fleshy fruits are particularly rich in volatiles that deter herbivores and attract seed dispersal agents. we have investigated how terpenes in citrus fruit peels affect the interaction between the plant, insects, and microorganisms. because limonene represents up to 97% of the total volatiles in orange (citrus sinensis) fruit peel, we chose to down-regulate the expression of a limonene synthase gene in ora ...201121525333
classification of plant associated bacteria using rif, a computationally derived dna marker.a dna marker that distinguishes plant associated bacteria at the species level and below was derived by comparing six sequenced genomes of xanthomonas, a genus that contains many important phytopathogens. this dna marker comprises a portion of the dnaa replication initiation factor (rif). unlike the rrna genes, dnaa is a single copy gene in the vast majority of sequenced bacterial genomes, and amplification of rif requires genus-specific primers. in silico analysis revealed that rif has equal or ...201121533033
the colrs system is essential for the hunger response of glucose-growing pseudomonas putida.abstract: background: the survival of bacteria largely depends on signaling systems that coordinate cell responses to environmental cues. previous studies on the two-component colrs signal system in pseudomonas putida revealed a peculiar subpopulation lysis phenotype of colr mutant that grows on solid glucose medium. here, we aimed to clarify the reasons for the lysis of bacteria. results: we present evidence that the lysis defect of p. putida colr mutant is linked to hunger response. a subpopul ...201121791104
diversity and plasticity of the intracellular plant pathogen and insect symbiont, 'candidatus liberibacter asiaticus', revealed by hyper variable prophage genes with intragenic tandem repeats.'candidatus liberibacter asiaticus' (las) is a psyllid-transmitted, phloem-limited alpha proteobacterium, and the most prevalent species of liberibacter associated with a devastating worldwide citrus disease known as huanglongbing (hlb). two related and hyper variable genes (hyvi and hyvii) were identified in the prophage regions of the psy62 las genome. sequence analyses of the hyvi/hyvii genes in 35 las dna isolates collected globally revealed hyvi gene contains up to12 nearly identical tandem ...201121784907
genome-wide mutagenesis of xanthomonas axonopodis pv. citri reveals novel genetic determinants and regulation mechanisms of biofilm formation.xanthomonas axonopodis pv. citri (xac) causes citrus canker disease, a major threat to citrus production worldwide. accumulating evidence suggests that the formation of biofilms on citrus leaves plays an important role in the epiphytic survival of this pathogen prior to the development of canker disease. however, the process of xac biofilm formation is poorly understood. here, we report a genome-scale study of xac biofilm formation in which we identified 92 genes, including 33 novel genes involv ...201121750733
antimicrobial activities of phenethyl isothiocyanate isolated from horseradish.phenethyl isothiocyanate (peitc) was obtained from horseradish. the preparation procedure was as follows: the horseradish powder was hydrolysed in the water first, and then, after filtration, the residue was extracted by petroleum ether; finally, peitc was isolated by silica gel column. the structure of peitc was identified by ir, ms, (1)h-nmr and (13)c-nmr chromatography methods. the inhibitory activities of peitc against gibberella zeae, xanthomonas axonopodis pv . citri, cytospora sp . and ph ...201121815843
the ubiquitous plasmid pxap41 in the invasive phytopathogen xanthomonas arboricola pv. pruni: complete sequence and comparative genomic analysis.the complete dna sequence of the 41ôçâ102-bp plasmid pxap41 from the invasive plant pathogen xanthomonas arboricola pv. pruni cfbp 5530 was determined and its 44 coding regions were annotated. comparative analysis with 15 xanthomonas plasmids and 19 complete genomes revealed that nearly one-fourth of this plasmid has high sequence identity to plasmid pxac64 and an 8.8-kb chromosomal region of xanthomonas axonopodis pv. citri strain 306 carrying genes that encode type iii effectors and helper pro ...201121732961
Bridging Taxonomic and Disciplinary Divides in Infectious Disease.Pathogens traverse disciplinary and taxonomic boundaries, yet infectious disease research occurs in many separate disciplines including plant pathology, veterinary and human medicine, and ecological and evolutionary sciences. These disciplines have different traditions, goals, and terminology, creating gaps in communication. Bridging these disciplinary and taxonomic gaps promises novel insights and important synergistic advances in control of infectious disease. An approach integrated across t ...201122086388
classification of a haemophilus influenzae abc transporter hi1470/71 through its cognate molybdate periplasmic binding protein, mola.mola (hi1472) from h. influenzae encodes a periplasmic binding protein (pbp) that delivers substrate to the abc transporter molb(2)c(2) (formerly hi1470/71). the structures of mola with molybdate and tungstate in the binding pocket were solved to 1.6 and 1.7 å resolution, respectively. the mola-binding protein binds molybdate and tungstate, but not other oxyanions such as sulfate and phosphate, making it the first class iii molybdate-binding protein structurally solved. the ∼100 μm binding affin ...201122078568
small heat shock proteins and α-crystallins: dynamic proteins with flexible functions.the small heat shock proteins (shsps) and the related α-crystallins (αcs) are virtually ubiquitous proteins that are strongly induced by a variety of stresses, but that also function constitutively in multiple cell types in many organisms. extensive research has demonstrated that a majority of shsps and αcs can act as atp-independent molecular chaperones by binding denaturing proteins and thereby protecting cells from damage due to irreversible protein aggregation. as a result of their diverse e ...201122177323
small heat shock proteins and α-crystallins: dynamic proteins with flexible functions.the small heat shock proteins (shsps) and the related α-crystallins (αcs) are virtually ubiquitous proteins that are strongly induced by a variety of stresses, but that also function constitutively in multiple cell types in many organisms. extensive research has demonstrated that a majority of shsps and αcs can act as atp-independent molecular chaperones by binding denaturing proteins and thereby protecting cells from damage due to irreversible protein aggregation. as a result of their diverse e ...201122177323
Fortunella margarita Transcriptional Reprogramming Triggered by Xanthomonas citri subsp. citri.ABSTRACT:201122078099
diffusible signal factor-mediated quorum sensing plays a central role in coordinating gene expression of xanthomonas citri subsp. citri.diffusible signal factor (dsf) family signal-mediated quorum sensing (qs) has been identified in many gram-negative bacteria. this qs pathway of xanthomonas spp. consists of three major qs components: rpff, rpfc, and rpfg. the rpff gene encodes a putative enoyl-coa hydratase that catalyzes the synthesis of the signal molecule. rpfc and rpfg serve as a two-component system for the perception and transduction of the extracellular dsf family signals. in order to further characterize the qs regulato ...201121995764
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