Detection of a quorum sensing signal molecule of Acidovorax avenae subsp. citrulli and its regulation of pathogenicity

Abstract

An efficient AHL ( N -acyl-homoserine lactone) bioassay strain, JZA1, of Agrobacterium tumefaciens was used to detect the AHL production from Acidovorax avenae subsp. citrulli [the pathogen causing bacterial fruit blotch (BFB) of melons], and the results showed that A. avenae subsp. citrulli produced a 3-O-C 8 -homoserine (HSL) type signal molecule. Gene aiiA , which could degrade AHL molecules, was transformed into A. avenae subsp. citrulli strain NJF10, creating strain NJF10- aiiA . The AHL production from NJF10- aiiA was significantly reduced compared with wild-type NJF10. Inoculation tests showed that NJF10- aiiA had an obvious reduction of virulence on watermelon fruits. Our finds showed that AHL production by A. avenae subsp. citrulli was related to its pathogenicity. This work might provide a novel way to control BFB by QS (quorum sensing) interference.