Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/30/2019
Publication Date: 12/19/2019
Citation: Lin, H., Shi, X. 2019. Molecular characterization and functional analysis of pilH in the pathogenicity of Xylella fastidiosa. Meeting Abstract.
Technical Abstract: Active movement mediated by bacterial twitching has been demonstrated to be an important component of the pathogenic mechanisms. In silico analysis suggests that PilH of X. fastidiosa regulates the type IV pilus system. To elucidate the roles of pilH in the twitching motility and virulence of X. fastidiosa, a pilH-deletion mutant (Xf'pilH) and complemented strain (Xf'pilH-C) were generated. The Xf'pilH mutant showed a reduction in cell-matrix adherence, cell-to-cell aggregation, and biofilm production compared to X. fastidiosa wild type and Xf'pilH-C. The typical colony peripheral fringe was not observed for Xf'pilH but was observed in colonies of wild type and Xf'pilH-C. Furthermore, the expression of type IV pilin pilV, pilX, fimbriae fimA, alginate synthesis algH, and virulence transcriptional regulator csrA, lexA, were down-regulated in Xf'pilH in comparison to wild type and Xf'pilH-C. Disease indexes of grapevines inoculated with Xf'pilH were low compared to grapevines inoculated with wild type and Xf'pilH-C. These results indicate that PilH contributes to the pathogenicity of X. fastidiosa via regulation of type IV pilus and affects twitching motility, cell aggregation and biofilm formation required for development of Pierce’s disease of grapevine.