The Effect of Quorum Sensing Inhibitor Bacteria on Pathogenicity of Pectobacterium atrosepticum Causal Agent of Potato Blackleg

Numerous species of bacteria employ a mechanism of intercellular communication known as quorum sensing (QS). Amongst protobacteria, several functions including production of virulence determinants in Pectobacterium atrosepticum are regulated in this way. The signal molecules involved in quorum sensing in P. atroseptium belong to the group of N- acyl homoserine lactones (N-AHLs). In this research, ten strains of AHL degrading Rhizobacteria were isolated from potato rhizosphere. According to ribotyping analysis, these isolates fell into three groups which members were identified as genera Bacillus, Arthrobacter, and Pseudomonas. All these isolates were capable to degrade both synthetic and natural N-AHL produced by P. atrosepticum strain SM1. In biocontrol experiment, Bacillus sp. and Arthrobacter sp. were significantly reduced the pathogenicity of P. atrosepticum strain in potato tubers and totally suppressed tissue maceration and blackleg symptoms on potato plants. Out of these results, AHL degrading bacteria might be highlighted and considered as useful agents in the biocontrol of bacterial plant diseases.