A GLYCOPROTEOMIC STUDY ON XANTHOMONAS CITRI CITRI

LANDONI, M; CARRAU, A; ORELLANO, EG; COUTO AS

Salta

Congreso; Joint LV AnnualSAIBMeeting andXIV PABMB CongressNovember 5-8, 2019 Salta, ARGENTINA; 2019

SAIB and PABMB

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 pathogenhost interaction and participate in the pathogenic processes, motility, biofilm formation, cell-cell interaction and immune system evasion. AGlycoproteomic study consists in the analysis of glycoproteins, including protein identities, glycosylation sites along with the glycan structures ofan organism in a specified condition. When the Xcc genome was completely sequenced, it presented three genes encoding for putative blue lightreceptors. As light is an important environmental signal, involving photoreceptor proteins that translate it into a biochemical signal, we have starteda glycoproteomic study of Xcc grown in darkness or under white light. SDS-PAGE showed differences in the glycoprotein profile in bothconditions. For this first approach, glycoproteins were fractionated by ConA chromatography and after trypsin digestion, glycopeptides wereanalyzed by HPLC-ESI-Orbitrap. Raw data were processed for protein identification and statistical analysis. Interestingly, from the 417glycoproteins identified, 14 were present exclusively when the bacterium was grown under light while 110, exclusively in darkness suggesting aninduction of glycosylation of proteins with high-mannose type oligosaccharides in this condition. Some of these proteins are involved in thepathogenic mechanism, motility, exopolysaccharide production and secretion systems.