Flagellin glycosylation in Ralstonia solanacearum and its role in virulence

VANDECAVEYE, AI; ORELLANO, EG; LANDONI, M; TONDO, ML; COUTO, AS

Buenos Aires

Simposio; 3rd Argentinian Symposium on Glycobiology GlycoAR 2019; 2019

The addition of carbohydrates to flagellin, structural subunit of thebacterial flagellum, has been reported in Gram-negative bacteria,being in many cases required for the assembly, stability andfunctionality of the flagellar filament. In the case of pathogenicbacteria, it has been shown to play an essential role in virulenceand in the evasion of host immune responses. Ralstoniasolanacearum (Rso) is the causal agent of the destructivebacterial wilt disease in more than 200 plant species, includingnumerous crops of agronomic interest. The aim of this work wasto characterize the glycosylation of the flagellin protein of Rsoand to initiate the functional study of the RSp0387 and RSp0388genes, encoding putative glycosyltransferases in the flagellargene cluster. Flagellin protein was extracted from liquid cultures,identified by HPLC-ESI analysis, and its glycosylation patternwas characterized by mass spectrometry and HPAEC-PAD,determining the presence of N- and O-glycans of 3 to 14 units ofhexose. Rso Rsp0387 and Rsp0388 deletion mutants weregenerated and physiologically characterized. The mutant strainsexhibited normal flagellar structures under TEM microscopy butreduced motility in swimming plates and significant differences inautoagglutination assays compared to the WT strain. Moreover,differences were observed among the disease progress curvesof the strains during tomato (Solanum lycopersicum) infectionassays.