A Quorum Quenching Bacterial Isolate Contains Multiple Substrate-Inducible Genes Encoding for Degradation of Diffusible Signal Factor.

In this study, we developed an efficient method for screening of highly active DSF-degradation microorganisms. Among them, strain Pseudomonas sp. HS-18 showed a superior DSF degradation activity. Bioinformatics and genetic analyses showed that at least 4 genes, designated as digA-D encoding fatty acyl-CoA ligase homologues, are responsible for DSF signal degradation. Interestingly, all the 4 dig genes were induced by exogenous DSF with digA being the most significantly induced. Expression of the dig genes in Xanthomonas campestris pv. campestris (Xcc) markedly reduced the accumulation of endogenous DSF, decreased production of virulence factors, and attenuated bacterial virulence on host plants. Similarly, application of strain HS-18 as a biocontrol agent could substantially reduce the disease severity caused by Xcc These results unveil the molecular basis of a highly efficient DSF degradation bacterial isolate, and presents useful genes and biocontrol agents for control of the infectious diseases caused by DSF-dependent bacterial pathogens.Importance Diffusible signal factor (DSF) represents a family of widely conserved quorum sensing signals involved in regulation of virulence factor production in many gram-negative bacterial pathogens. In this study, we developed a novel and efficient method for screening of highly active DSF-degradation microorganisms. With this method, we identified a bacterial isolate Pseudomonas sp. HS-18 with a superb DSF degradation activity. We furt...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research