A glycoproteomic study on Xanthomonas citri citri.

LANDONI M.; CARRAU A.; ORELLANO E.G; COUTO A.S

Salta

Congreso; LV ANNUAL SAIB- XIV PABMB; 2019

Sociedad Argentina de Bioquímica y Biologia Molecular

Xanthomonas citri subsp. citri (Xcc) is a Gram-negative bacterium that produces citrus canker, a disease that affects all citrus commercial varieties. Protein glycosylation is a post-translational modification essential to modulate protein structure and function. Glycans are involved in the pathogen-host interaction and participate in the pathogenic processes, motility, biofilm formation, cell-cell interaction and immune system evasion. A Glycoproteomic study consists in the analysis of glycoproteins, including protein identities, glycosylation sites along with the glycan structures of an organism in a specified condition. When the Xcc genome was completely sequenced, it presented three genes encoding for putative blue light receptors. As light is an important environmental signal, involving photoreceptor proteins that translate it into a biochemical signal, we have started a glycoproteomic study of Xcc grown in darkness or under white light. SDS-PAGE showed differences in the glycoprotein profile in both conditions. For this first approach, glycoproteins were fractionated by ConA chromatography and after trypsin digestion, glycopeptides were analyzed by HPLC-ESI-Orbitrap. Raw data were processed for protein identification and statistical analysis. Interestingly, from the 417 glycoproteins identified, 14 were present exclusively when the bacterium was grown under light while 110, exclusively in darkness suggesting an induction of glycosylation of proteins with high-mannose type oligosaccharides in this condition. Some of these proteins are involved in the pathogenic mechanism, motility, exopolysaccharide production and secretion systems.