IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Structural comparison of the wild type and rfb303 mutant LPS from Xanthomonas axonopodis pv. citri
Autor/es:
CASABUONO AC, PETROCELLI S, OTTADO J, ORELLANO EG, COUTO AS.
Lugar:
Potrero de Funes, San Luis
Reunión:
Congreso; XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011
Institución organizadora:
Sociedad Argentina de Investigación en Bioquímica y Biología Molecular
Resumen:
Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, provoking defoliation and premature fruit drop with concomitant economical damage. In plant pathogenic bacteria, lipopolysaccharides (LPSs) are important virulence factors, and they are being increasingly recognized as major PAMPs for plants. We have previously characterized the LPS isolated from Xac wild type and Xacwzt mutant. In the present work the LPS obtained from Xacrfb303, a mutant in rfb303 gene coding for a core glycosyltransferase, was studied in order to determine the role of this moiety of Xac LPS in citrus canker. LPSs from harvested cells were extracted with a 50% phenol/ water mixture. The aqueous phases were dialyzed and LPS preparations were evaluated by SDS-PAGE. Purified LPS was hydrolyzed with 1% acetic acid, the precipitated lipid A was recovered by ultracentrifugation and the solution containing the sugar moiety (called oligosaccharide) was separated and lyophilized. When the UV-MALDI-TOF ms analysis of the Lipid A obtained from rfb303 was performed, a spectra showing similar species to the one obtained for the wild type Lipid A was detected. However, penta-acylated species bearing two pyrophosphoethanolamine groups were predominant. Total hydrolysis of the oligosaccharide moiety and HPAEC-PAD analysis revealed that the same monosacharides than the wild type were present, but in a different relationship. These structural differences were confirmed by UV-MALDI-TOF ms analysis.