Abstract:LuxR-type regulators are a group of proteins that play important roles in transcriptional regulation in Gram-negative bacteria. This study investigated a putative LuxR-type regulator LuxR-2460 in Acidovorax citrulli,the causal agent of bacterial fruit blotch of watermelon and melon.The predicted amino acid sequence of LuxR-2460 contains two conserved domains, which is consistent with that of other LuxR-type regulators: a DNA-binding HTH domainin the C-terminaland a REC domain in the N-terminal. A deletion mutant of the luxR-2460 gene demonstrated reduced virulence, weakened swimming and twitching motility, and increased biofilm production. Additionally, the luxR-2460 deletion mutant had a decrease in the expression of fliR, and may therefore regulate flagellation.Given the importance of this gene in the virulence of A. citrulli on watermelon, it is a promising target for future studies on disease control.