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:With the aid of a biochip, carrying representative sequences from approximately 2200 sequences from the genome of isolate 9a5c from X. fastidiosa (Xf), microarray-based comparisons have been performed with 8 different Xf isolates obtained from coffee plants.
Project description:Investigation of whole genome gene expression level changes in Xylella fastidiosa grown in minimal media XFM and XFM supplied with pectin or glucan (Host polysaccharides) , compared to cell grown in the complex media PWG. The cells grown in the minimal medium XFM supplied with host polysaccharides specially pectin are transmissible by the insect vector when delivered to the vector through artificial diet system. This does not happen with cells grown in the complex media. 4 (4 plex chips) study using total RNA recovered from 4 independents replicates for Xylella fastidiosa grown on PWG, XFM, XFM-glucan and XFM-pectin.
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
