A LuxS-dependent cell-to-cell language regulates social behavior and development in Bacillus subtilis.
Cell-to-cell communication in bacteria is mediated by quorum-sensing systems (QSS) that produce chemical signal molecules called autoinducers (AI). In particular, LuxS/AI-2-dependent QSS has been proposed to act as a universal lexicon that mediates intra- and interspecific bacterial behavior. Here we report that the model organism Bacillus subtilis operates a luxS-dependent QSS that regulates its morphogenesis and social behavior. We demonstrated that B. subtilis luxS is a growth-phase-regulated gene that produces active AI-2 able to mediate the interspecific activation of light production in Vibrio harveyi. We demonstrated that in B. subtilis, luxS expression was under the control of a novel AI-2-dependent negative regulatory feedback loop that indicated an important role for AI-2 as a signaling molecule. Even though luxS did not affect spore development, AI-2 production was negatively regulated by the master regulatory proteins of pluricellular behavior, SinR and Spo0A. Interestingly, wild B. subtilis cells, from the undomesticated and probiotic B. subtilis natto strain, required the LuxS-dependent QSS to form robust and differentiated biofilms and also to swarm on solid surfaces. Furthermore, LuxS activity was required for the formation of sophisticated aerial colonies that behaved as giant fruiting bodies where AI-2 production and spore morphogenesis were spatially regulated at different sites of the developing colony. We proposed that LuxS/AI-2 constitutes a novel form of quorum-sensing regulation where AI-2 behaves as a morphogen-like molecule that coordinates the social and pluricellular behavior of B. subtilis.
Lombardía
Esteban
E
Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario (2000), Argentina.
Rovetto
Adrián J
AJ
Arabolaza
Ana L
AL
Grau
Roberto R
RR
D001412:Bacillus subtilis / Q000166:cytology* / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development; D013437:Carbon-Sulfur Lyases; D004268:DNA-Binding Proteins / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives / Q000235:genetics / Q000378:metabolism; D007783:Lactones / Q000378:metabolism; D008124:Locomotion; D049408:Luminescent Agents / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D007783:Lactones; D049408:Luminescent Agents; C091088:N-octanoylhomoserine lactone; C080950:Spo0A protein, Bacillus subtilis; D014157:Transcription Factors; C076733:FlaD protein, Bacteria; D006714:Homoserine; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria