Lysobacter enzymogenes Uses Two Distinct Cell-Cell Signaling Systems for Differential Regulation of Secondary-Metabolite Biosynthesis and Colony Morphology

• DOI: 10.1128/aem.01841-13
• Publication Date: 2013-08-24T05:03:54Z
• Authors: Guoliang Qian; Yulan Wang; Yiru Liu; Feifei Xu; Ya-Wen He; Liangcheng Du; Vittorio Venturi; Jiaqin Fan; Baishi Hu; Fengquan Liu
• Keywords: 0301 basic medicine; Xanthomonas; Reverse Transcriptase Polymerase Chain Reaction; Bacterial Toxins; Secondary Metabolism; Gene Expression Regulation, Bacterial; Pigments, Biological; Microarray Analysis; Real-Time Polymerase Chain Reaction; 03 medical and health sciences; Lysobacter; Escherichia coli; Microbial Interactions

ABSTRACT

Lysobacter enzymogenes is a ubiquitous environmental bacterium that is emerging as a potentially novel biological control agent and a new source of bioactive secondary metabolites, such as the heat-stable antifungal factor (HSAF) and photoprotective polyene pigments. Thus far, the regulatory mechanism(s) for biosynthesis of these bioactive secondary metabolites remains largely unknown in L. enzymogenes . In the present study, the diffusible signal factor (DSF) and diffusible factor (DF)-mediated cell-cell signaling systems were identified for the first time from L. enzymogenes . The results show that both Rpf/DSF and DF signaling systems played critical roles in modulating HSAF biosynthesis in L. enzymogenes . Rpf/DSF signaling and DF signaling played negative and positive effects in polyene pigment production, respectively, with DF playing a more important role in regulating this phenotype. Interestingly, only Rpf/DSF, but not the DF signaling system, regulated colony morphology of L. enzymgenes . Both Rpf/DSF and DF signaling systems were involved in the modulation of expression of genes with diverse functions in L. enzymogenes , and their own regulons exhibited only a few loci that were regulated by both systems. These findings unveil for the first time new roles of the Rpf/DSF and DF signaling systems in secondary metabolite biosynthesis of L. enzymogenes .