|SHI, XIANGYANG - Foreign Agricultural Service (FAS, USDA)|
Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/16/2016
Publication Date: 7/30/2016
Citation: Shi, X., Lin, H. 2016. The chemotaxis regulator pilG of Xylella fastidiosa is required for virulence in Vitis vinifera grapevines. American Phytopathological Society Abstracts. p. 714.
Technical Abstract: Xylella fastidiosa is a Gram-negative, xylem-limited pathogenic bacterium that causes Pierce’s disease of grapevines. Type IV pili of X. fastidiosa are regulated by pilG, a chemotaxis regulator in Pil-Chp operon involving signal transduction pathways. To elucidate the role of pilG in twitching motility and pathogenicity, phenotypes of wild type, pilG-mutant, and a complementary strain were characterized. While in vitro studies showed that all tested strains had similar growth curves, mutant Xf'pliG exhibited a twitching defective phenotype and significant reduction in biofilm formation and cell-cell aggregation. Greenhouse in planta experiment further confirmed that grapevines infected with Xf'pilG showed very mild PD symptoms whereas grapevines inoculated with X. fastidiosa wild type and Xf'pilG-C developed typical PD symptoms. These results demonstrate that pilG of X. fastidiosa is required for twitching motility and full virulence.