A Mutation of a Putative NDP-Sugar Epimerase Gene in Ralstonia pseudosolanacearum Attenuates Exopolysaccharide Production and Bacterial Virulence in Tomato Plant

<i>Ralstonia solanacearum</i> species complex (RSSC) is a soil borne plant pathogen causing bacterial wilt on various important crops, including Solanaceae plants. The pathogens within the RSSC produce exopolysaccharide (EPS), highly complicated nitrogen-containing heteropolymeric polysaccharide, as major virulence factor. However, biosynthetic pathway of EPS in has not been fully characterized. To identify genes production beyond gene operon, we selected EPS-defective mutants <i>R. pseudosolanacearum</i> strain SL341 from Tn5-inserted mutant pool. Among several mutants, identified mutant, SL341P4, with Tn5-insertion encoding putative NDP-sugar epimerase, membrane protein sugar-modifying moiety, reverse orientation to biosynthesis cluster. This showed similar other epimerases involved many phytopathogens. Mutation epimerase reduced and biofilm formation pseudosolanacearum</i>. Additionally, SL341P4 exhibited disease severity incidence tomato plants compared wild-type without alteration multiplication. These results indicate that required for