Skip to main content
ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Publications at this Location » Publication #334341
Title: Type III secretion system genes hrcJ and hrpE affect virulence, hypersensitive response and biofilm formation of group II strains of Acidovorax citrulli

Author
item GUAN, WEI - Chinese Academy Of Agricultural Sciences
item AN, XIN - Chinese Academy Of Agricultural Sciences
item Huang, Qi
item WANG, TIELIN - Chinese Academy Of Agricultural Sciences
item YANG, YUWEN - Chinese Academy Of Agricultural Sciences
item ZHAO, TINGCHANG - Chinese Academy Of Agricultural Sciences

Submitted to: Journal of Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2022
Publication Date: 8/15/2022
Citation: Guan, W., An, X., Huang, Q., Wang, T., Yang, Y., Zhao, T. 2022. Type III secretion system genes hrcJ and hrpE affect virulence, hypersensitive response and biofilm formation of group II strains of Acidovorax citrulli. Journal of Phytopathology. https://doi.org/10.3389/fsufs.2022.995894.
DOI: https://doi.org/10.3389/fsufs.2022.995894

Interpretive Summary: Bacterial fruit blotch disease caused by the bacterium Acidovorax citrulli is a serious problem worldwide in watermelon and melon production. We studied the functions of two genes involved in one of the secretion systems of the bacterium, and found the genes positively affect the ability of the bacterium to cause disease symptoms in watermelon and melon plants. However, the genes negatively control the ability of the bacterium to bind to the fruit surface. Our study will help scientists to better understand this bacterium in order to help watermelon and melon farmers to effectively control the disease it causes.

Technical Abstract: Bacterial fruit blotch (BFB) caused by Acidovorax citrulli is a worldwide threat to watermelon and melon production. The type III secretion system (T3SS) plays an important role in the virulence of A. citrulli in its host plants and to induce the hypersensitive response (HR) in its non-host plants. Little is known, however, about the contribution of the T3SS to biofilm formation in A. citrulli. We mutated two T3SS-related genes, hrcJ and hrpE respectively, and compared the mutants with their wild-type strain Aac-5 of A. citrulli, for virulence, HR, and biofilm formation. Both mutants showed significantly reduced virulence in watermelon and melon seedlings and in their ability to induce the HR in tobacco leaves. Such phenotypes were significantly restored to the wild-type levels when the mutant strains were complemented with the wild-type hrcJ and hrpE genes. Interestingly, the two T3SS-related gene mutants also displayed enhanced ability to form biofilm, suggesting a different role of biofilm in the virulence of the group II stains of A. citrulli.