Abstract：LuxR homologues are the main component of LuxI/LuxR circus in quorum sensing (QS) of Gram- negative bacteria. In this study, an internal fragment of luxR homologue from Acidovorax avenae subsp.citrulli was amplified by PCR, the luxR insertion mutant was constructed by homologue recombination. In comparison with the wild-type strain, the luxR deletion mutant(△luxR) had a significantly reduced ability to form acyl homoserine lactones (AHLs), which are quorum-sensing molecules. Tolerance to antibiotics were enhanced in the △luxR than that of the wild-type strain. △luxR had reduced virulence on melon(Cucuumis melo var. cantalupensis) leaves. RT-PCR indicated that LuxR protein regulated expression of the luxI gene. The study of luxR gene is to provide basic data for the prevention and control of Acidovorax avenae subsp. citrulli using the technology of signal interference.
