Location: Floral and Nursery Plants ResearchTitle: Quorum-sensing contributes to virulence, twitching motility, seed attachment and biofilm formation in the wild type strain Aac-5 of Acidovorax citrulli Author
Submitted to: Microbial Pathogenesis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2016
Publication Date: 9/1/2016
Citation: Wang, T., Guan, W., Huang, Q., Yang, Y., Yan, W., Sun, B., Zhao, T. 2016. Quorum-sensing contributes to virulence, twitching motility, seed attachment and biofilm formation in the wild type strain Aac-5 of Acidovorax citrulli. Microbial Pathogenesis. 100:133-140. Interpretive Summary: Bacterial fruit blotch disease in cucurbits is caused by the bacterium Acidovorax citrulli. We studied the roles of quorum sensing (QS), which is a system of stimuli and response signaling that is correlated to population density of the bacterium. We found that QS positively affects the bacterium’s gliding motility and ability to cause disease symptoms in watermelon plants, but negatively controls for the ability of the bacterium to bind to its surface and to watermelon seeds. Our study will help scientists to better understand this bacterium in order to help watermelon farmers effectively control the disease it causes.
Technical Abstract: Acidovorax citrulli is a seed-borne pathogen that causes bacterial fruit blotch of cucurbits including melon and watermelon. We investigated the roles of quorum sensing in the wild-type group II strain Aac-5 of A. citrulli by generating aacR and aacI knockout mutants and their complementation strains. We found that twitching motility and virulence were reduced, but biofilm formation and seed attachment were increased significantly in the two mutants as compared to the wild type strain. Deletion of aacR and aacI, however, had no effect on swimming motility and polar flagella formation of Aac-5. Furthermore, deletion of aacR resulted in reduced gene expression of hrpE, hrcN and pilT, while deletion of aacI affected only the expression of hrpE and pilT, not hrcN.