Biological control of pathogen communication in the rhizosphere: A novel approach applied to potato soft rot due to Pectobacterium atrosepticum

Background and aims

Recent basic knowledge on the regulation of virulence in pectinolytic bacteria revealed pathogen communication via quorum sensing signals as a crucial event for the expression of virulence and the onset of disease symptoms. In this paper, we present and discuss advances in a new biocontrol approach based on the interference of microbial communication involved in the cellular density and microenvironment sensoring.

Methods

This emerging strategy consists in the characterization of the signaling molecules used by the target pathogen, then the use of harmless structural analogs to stimulate plant associated-microflora able to degrade both molecule families.

Results

The biocontrol method has been applied for the first time for the control of Pectobacterium atrosepticum. This psychrotrophic bacterium synthesizes N-acyl-homoserine lactones involved in cell-to-cell communication that triggers soft rot and blackleg of potato. The use of the gamma-caprolactone stimulant promotes the emergence and catabolic activity of Rhodococcus erythropolis antagonistic populations in the potato rhizosphere.

Conclusions

Rhodococcus bacteria have the ability to disrupt the quorum sensing-based communication of P. atrosepticum by degrading N-acyl-homoserine lactone signaling molecules and prevent disease.