Project description:Genome sequence analysis of the bacterium Xylella fastidiosa revealed the presence of two genes, named rpoE and rseA, predicted to encode an ECF sigma factor and an anti-sigma factor, respectively. In this work, an rpoE null mutant was constructed in the citrus strain J1a12 and shown to be sensitive to exposure to heat shock and ethanol. To identify the X. fastidiosa σE regulon, global gene expression profiles were obtained by DNA microarray analysis of bacterial cells under heat shock identifying 23 sigmaE-dependent genes. Keywords: stress response, heat shock, rpoE mutant strain
Project description:This is the study of the Heat Shock response of phytopathogenic bacteria Xylella fastidiosa. This series keeps the 25 minutes 40oC stimulus response (Aug 2005). Keywords: stress response; heat shock response
Project description:Xylella fastidiosa is a phytopathogenic bacterium responsible for diseases in many economically important crops. Although different strains have been studied, little is known about X. fastidiosa stress responses. One of the best characterized stresses in bacteria is the heat shock response, which induces the expression of specific genes to prevent protein misfolding and aggregation, and to promote degradation of the irreversibly denatured polypeptides. To investigate X. fastidiosa genes involved in the heat shock response, we performed a whole genome microarray analysis in a time-course experiment. Globally, 261 genes were induced (9.7%) and 222 genes were repressed (8.3%). The expression profiles of the differentially expressed genes were grouped and their expression patterns were validated by quantitative RT-PCR experiments. As expected, genes that presented the higher induction rates encoded chaperones and proteases. We determined the transcription start site of six heat shock inducible genes and analyzed their promoter regions, which allowed us to propose a putative consensus for 32 promoters in Xylella and suggest additional genes as putative members of this regulon. Besides the induction of classical heat shock protein genes, we observed the up-regulation of virulence-associated genes such as vapD, hemagglutinins, hemolysin and xylan degrading enzymes, which may indicate the importance of heat stress to bacterial pathogenesis. In addition, we observed the repression of genes related to fimbriae, aerobic respiration, protein biosynthesis, and the induction of genes related to the extracytoplasmic stress response and some phage-related genes, revealing the complex network of genes that work together in response to heat shock. Keywords: stress response; heat shock response
Project description:To investigate the role(s) of a cold shock protein homolog (Csp1) in plant pathogenic bacteria Xylella fastidiosa, we compared transcriptome profiles between wild type and a csp1 deletion mutant (Δcsp1) using long read Nanopore RNA sequencing.
Project description:Xylella fastidiosa regulates traits important to both virulence of grape as well as colonization of sharpshooter vectors via its production of a fatty acid signal molecule known as DSF whose production is dependent on rpfF. While X. fastidiosa rpfF mutants exhibit increased virulence to plants they are unable to be spread from plant to plant by insect vectors. To gain more insight into the traits that contribute to these processes, a DNA microarray for this species was designed and utilized to determine the RpfF-dependent regulon by transcriptional profiling. A total of 447 genes whose expression was significantly different between the wild type and an rpfF mutant (FDR<0.05) were identified when cells were grown in PW liquid medium. Among them, 165 genes were down-regulated in the rpfF mutant compared to the wild type strain whereas 282 genes were over-expressed. RpfF function was required for regulation of eleven regulatory and sigma factors including rpfE, yybA, PD1177, glnB, rpfG, PD0954, PD0199, PD2050, colR, rpoH, and rpoD. In general, RpfF is required for regulation of genes involved in attachment and biofilm formation, enhancing expression of hemagglutinin genes hxfA and hxfB and suppressing most type IV pili and gum genes. A large number of other RpfF-dependent genes that might contribute to virulence or insect colonization were also identified such as those encoding hemolysin, colicin V, as well as genes with unknown functions.
Project description:Xylella fastidiosa regulates traits important to both virulence of grape as well as colonization of sharpshooter vectors via its production of a fatty acid signal molecule known as DSF whose production is dependent on rpfF. While X. fastidiosa rpfF mutants exhibit increased virulence to plants they are unable to be spread from plant to plant by insect vectors. To gain more insight into the traits that contribute to these processes, a DNA microarray for this species was designed and utilized to determine the RpfF-dependent regulon by transcriptional profiling. A total of 447 genes whose expression was significantly different between the wild type and an rpfF mutant (FDR<0.05) were identified when cells were grown in PW liquid medium. Among them, 165 genes were down-regulated in the rpfF mutant compared to the wild type strain whereas 282 genes were over-expressed. RpfF function was required for regulation of eleven regulatory and sigma factors including rpfE, yybA, PD1177, glnB, rpfG, PD0954, PD0199, PD2050, colR, rpoH, and rpoD. In general, RpfF is required for regulation of genes involved in attachment and biofilm formation, enhancing expression of hemagglutinin genes hxfA and hxfB and suppressing most type IV pili and gum genes. A large number of other RpfF-dependent genes that might contribute to virulence or insect colonization were also identified such as those encoding hemolysin, colicin V, as well as genes with unknown functions. Two samples and one time-points experiment. Two biological and dye-swap replicates of each strain were used.