Regulation of social behavior and quorum sensing in Bacillus subtilis

LOMBARDÍA E., ROVETTO A., COULLERY R., GRAU R

Mar del Plata

Congreso; Reunión Anual Congreso SAIB; 2007

SAIB

Bacteria not only behave as self-sufficient individuals but also act as communities capable of cell-cell communication. This social interaction leads to the coordination of communitarian activities that resemble, in their complexity, the behaviors observed in multicellular organisms. This microbial phenomenon is known as quorum sensing (QS), a process by which bacteria monitor their cell population density by measuring the concentration of small secreted signal molecules called autoinducers. AI-2 dependent QS have been reported as a bacterial Esperanto for intra and inter-specific bacterial communication. Recently, we reported that, B. subtilis LuxS/AI-2-dependent QS act as an intraspecific bacterial signal required for biofilm formation, sliding motility and structure of sophisticated aerial colonies that behaved as giant fruiting bodies. In this work, we demonstrated the existence of a negative regulator of the luxS gene and its role during the onset of QS, sporulation, biofilm development and fruiting body formation. Additionally, we show evidences of the role of an ABC transporter in the incorporation of AI-2 to the cell and quorum quenching. The AI-2 dependent sliding motility studies bring about an unexpected and interesting role of the master regulator Spo0A in cell-cell recognition on solid surfaces.