Molecular and functional characterization of proteins potentially related to the phytopatogenicity of biofilm-forming bacteria Xylella fastidiosa

Abstract

With the sequencing of the genome of the bacterium Xylella fastidiosa 9a5c strain, there was a large increase in information related to their physiology and pathogenesis, but many of the proteins identified in the analysis of its genome does not have predicted functions and are classified as either hypothetical protein of unknown function . Thus, this project aims to assess the biological functions of proteins identified in sequencing projects to elucidate the pathogenic processes. Therefore, this study aims to characterize functionally seven proteins named: ycjZ (ORF Xf1480) operon system toxin-antitoxin (Xf2162, Xf2163 2), Tolc (ORF Xf2255) VirJ (ORF Xf Xf0617 and 2329) and VapD (ORF Xfb0051). The first show high similarity to members of the family of LysR-type transcriptional regulators (LTTR), which participates in the regulation of genes involved in cell division, the quorum sense, in biofilm formation, and virulence in response to oxidative stress. The other six proteins are inserted in different metabolic processes, but no less important, such as formation of efflux pump (Tolc) system, type IV secretion of macromolecules and horizontal transfer of DNA (ACVB) and proteins that respond to variations in temperature (VapD). Functional characterization include the production of antibodies for each target protein, followed by immunodetection during different stages of biofilm formation of X. fastidiosa. Additionally, protein expression is also quantified using the technique of qRT-PCR using plants infected oranges that exhibit chiorosis, while the structural characterization tests will be understood by Circular Dichroism (CD), and Exclusion Chromatography Molecular Weight. This study opens a new perspective for understanding the biological role of these proteins in biofilm development and pathogenicity of X. fastidiosa and contribute to recent studies of global gene expression by microarray, performed by the group of APTA Citrus Center (IAC / Cordeirópolis). (AU)