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 quorumsensing (QS). Amongst protobacteria, several functions including production of virulencedeterminants in Pectobacterium atrosepticum are regulated in this way. The signal molecules involvedin quorum sensing in P. atroseptium belong to the group of N- acyl homoserine lactones (N-AHLs). Inthis 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 identifiedas genera Bacillus, Arthrobacter, and Pseudomonas. All these isolates were capable to degrade bothsynthetic 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. atrosepticumstrain in potato tubers and totally suppressed tissue maceration and blackleg symptoms on potatoplants. Out of these results, AHL degrading bacteria might be highlighted and considered as usefulagents in the biocontrol of bacterial plant diseases.

Keywords:

AHL degradation , Pectobacterium atrosepticum , Quorum quenching