Project description:Transcriptional profiling of low-iron stimulon and XibR influenced regulon using wild-type Xcc 8004 and xibR mutant grown under iron-replete and iron-deplete conditions. Trancriptional analysis under iron-deplete condition, mimicking in planta environment, provides greater insights into expression pattern of several virulence-associated functions under low-iron. A genetic screen sggested the involvement of XibR (Xanthomonas iron binding regulator) in iron-uptake and metabolism. Present transcriptional analysis suggested the co-regulation of virulence associated functions including siderophore biosynthesis, motility, chemotaxis and typeIII effectors by a novel transcriptional regulator of NtrC family protein XibR and iron avability.
Project description:We performed a transcriptomic analysis of the necrotrophic bacteria Xanthomonas campestris pv. campestris exposed to two different isothiocyanates (allyl-isothiocyanate and indol-3-carbinol), searching for mechanisms of adaptation and detoxification of these chemicals.
Project description:Xylem sap of young cabbage plantlets was recovered from root pressure exudation and used as a growth medium for the vascular pathogen Xanthomonas campestris pv campestris, the causative agent of the black rot of Brassicaceae.
Project description:Bacteria of the genus Xanthomonas are economically important plant pathogens. Pathogenicity of Xanthomonas spp. depends on the type III-secretion system and additional virulence determinants. The number of sequenced Xanthomonas genomes increases rapidly, however, accurate annotation of these genomes is difficult, because it relies on gene prediction programs. In this study, we used a mass-spectrometry (MS)-based approach to identify the proteome of Xanthomonas campestris pv. vesicatoria (Xcv) also known as X. euvesicatoria, a well-studied member of plant-pathogenic Xanthomonadaceae. Results Using different culture conditions, MS-datasets were searched against a six-frame-translated genome database of Xcv. In total, we identified 2,593 proteins covering 55% of the Xcv genome, including 764 hitherto hypothetical proteins. Our proteogenomic approach identified 30 new protein-coding genes and allowed correction of the N-termini of 50 protein-coding genes. For five novel and two N-terminally corrected genes the corresponding proteins were confirmed by immunoblot. Furthermore, our data indicate that two putative type VI-secretion systems encoded in Xcv play no role in bacterial virulence which was experimentally confirmed.
Project description:Xanthomonas is one important model microbe to study the molecular determinants of virulence and host range of pathogens since Xanthomonas is capable of infecting numerous monocotyledonous and dicotyledonous plants. Among the plant diseases caused by Xanthomonas, X. citri subsp. citri (Xcc) causes citrus canker, which has significant impact on citrus production. Xcc is classified into different strains primarily by host range including A and Aw. The A (Asiatic) strain (XccA) has a wide host range and is most virulent, whereas Aw (Wellington) strain has restricted host range including Key or Mexican lime and alemow. We hypothesized that not only gene content but also gene expression contributes to the difference in virulence and host range of closely related strains. To test our hypothesis, comparative genomic and transcriptome analyses were conducted to study the two closely related Xcc A and Aw strains. The genome of X. citri subsp. citri strain Aw12879 (Xcaw) was completely sequenced using 454 Pyrosequencing, Illumina sequencing and Optical mapping. The finished genome (5.3 Mb chromosome and two plasmids pXcaw19 and pXcaw58) of Xcaw was annotated, curated and compared with XccA genome. Protein blast revealed multiple genes including type III secretion system (TIIISS) effectors xopAF and xopAG are present in Xcaw but absent in XccA. Comparative genomic analysis showed various changes in genes encoding LPS and type IV secretion system. Furthermore, RNA-Seq was used to compare expression profile of Xcaw and XccA in nutrient rich (NB) medium and XVM2 medium which is known to mimic the intercellular space of plant cells using Illumina sequencing. Multiple avirulence/effector genes were over-expressed in Xcaw compared to XccA which might contribute to the limited host range of Xcaw compared to XccA. The overexpression of genes involved in cell wall degradation, attachment, ROS (reactive oxygen species) scavenging, nutrient transportation in XccA might contribute to its expanding of host range. Our data suggest that both gene content and gene expression contribute to difference in virulence and host range of bacterial pathogens. This study lays the foundation to further characterize the mechanisms for virulence and host range of strains of X. citri subsp. citri and other bacterial pathogens.
Project description:Black rot, caused by Xanthomonas campestris pv. campestris (Xcc) is one of the most devastating diseases of cruciferous crops worldwide. The pathogen infects and multiplies in plant vascular tissues and, as the disease progresses, the veins of infected tissues turn black and characteristic V-shaped lesions appear along the margins of leaves.The aim of this work is to identify differentially expressed genes from Brassica oleracea during early infection by Xcc, in an attempt to identify proteins related to resistance. Cabbge seedlings were inoculated with Xanthomonas campestris pv campestris (Xcc) suspension and cabbage gene expression at 6h., 24h. And 48h. After inoculation was assessed with help of Brassica 95k EST microarray chip.
Project description:Due to low numbers and poor accessibility of host cells that are targeted for effector delivery, the actual biological functions of most effectors remain elusive. Here, we developed a novel Isolation Nuclei TArgeted by Bacterial Effectors (INTABE) system, which facilitates selectively recovering nuclei of the cells in Arabidopsis thaliana plants that have received type-III effectors of pathogenic Xanthomonas bacteria. Using these nuclei as studying materials, we analysed changes in host gene expression and their correlation with changes in DNA methylation induced by Xanthomonas effector Outer Protein D (XopD).
Project description:Black rot, caused by Xanthomonas campestris pv. campestris (Xcc) is one of the most devastating diseases of cruciferous crops worldwide. The pathogen infects and multiplies in plant vascular tissues and, as the disease progresses, the veins of infected tissues turn black and characteristic V-shaped lesions appear along the margins of leaves.The aim of this work is to identify differentially expressed genes from Brassica oleracea during early infection by Xcc, in an attempt to identify proteins related to resistance.
Project description:Transcriptional profiling of Xanthomonas campestris pv. campestris 8004 comparing control wild type strain with ravA (or ravS or ravR) mutant The effects of mutating ravS, ravR and ravA on EPS synthesis, biofilm production and motility were very different , the factors responsible for these differences are not clear. With comparative analysis of the regualtion pathways by RavS, RavR and RavA, we can indentify different genes regulated by these three genes and maybe explain the different phenotypes caused by these genes mutations.
