The ComP-ComA Quorum System Is Essential For “Trojan horse” Like Pathogenesis in Bacillus nematocida

Abstract

Bacillus nematocida B16 has been shown to use “Trojan horse” mechanism in pathogenesis that has characteristics of “social” behavior. The ComP-ComA system, a conserved quorum sensing system in the genus Bacillus, functions in many physiological processes including competence development, lipopeptide antibiotic surfactin production, degradative enzyme production and even some unknown functions. Here we investigated the requirement of ComP-ComA system in B. nematocida B16 for its pathogenicity against nematodes. The ΔcomP mutant displayed deficiencies in attracting and killing nematodes, due to the absence of attractive signal molecules and the decreased expressions of virulence factors, respectively. Contrarily, a complemented comP mutant at least partially resumed its pathogenicity. Our data from transcriptional analysis further confirmed that this signaling system directly or indirectly regulated the expressions of two major virulence proteases in the infection of B. nematocida B16. Bioinformatics analyses from comparative genomics also suggested that the potential target genes of transcription factor ComA were involved in the processes such as the synthesis of attractants, production of extracellular degradative enzymes and sortase, secondary metabolites biosynthesis, regulation of transcription factors, mobility, as well as transporters, most of which were different from a saprophytic relative B. subtilis 168. Therefore, our investigation firstly revealed that the participation and necessity of ComP-ComA signaling system in bacterial pathogenesis.

What renders Bacilli genetically competent? A gaze beyond the model organism

“…In Bacillus nematocida B16, ComA~P target genes are involved in the infection process of the bacterial pathogens by triggering the synthesis of attractants and production of virulence-associated proteases. ComP/ComA-induced signalling thus clearly differs from that of the saprophytic B. subtilis 168 (Deng et al 2013). In general, the comQXPA cluster is rather poorly conserved; B. megaterium, for instance (referring to the genomes of QM B1551 and DSM319), lacks the whole set of genes (Eppinger et al 2011).…”

ResDE Two-Component Regulatory System Mediates Oxygen Limitation-Induced Biofilm Formation by Bacillus amyloliquefaciens SQR9

“…Increased DegU phosphorylation significantly improved the complex colony architecture, biofilm formation, root colonization, and antibiotic production of B. amyloliquefaciens SQR9 (33). In B. subtilis, the ComPA system functions in the development of competence, the production of the lipopeptide antibiotic surfactin, degradative enzyme production, and even some unknown functions (34,35). The LytST system is believed to function in programmed cell death (PCD) and autolysis by sensing a decrease in membrane potential, while genomic DNA released by the lysed bacteria is essential for biofilm stability and intercellular adhesion (36)(37)(38).…”

The Signaling Pathway of Caenorhabditis elegans Mediates Chemotaxis Response to the Attractant 2-Heptanone in a Trojan Horse-like Pathogenesis

“…The volatile compounds of 2-heptanone has also been shown as one of the most important attractants since the absence of 2-heptanone would significantly weaken the capability to attract nematodes (35). In our current investigation, we explored the receptor and transductory pathway in C. elegans using 2-heptanone as a ligand.…”