Quorum Sensing in Competence and Sporulation
In several Gram-positive bacteria, competence and sporulation are few of several physiological processes controlled by quorum sensing (QS). Competence is a phenomenon wherein a bacterium acquires extracellular DNA for its maintenance. Only a fraction of cells (10–20 %), in a population, develop competence, at a particular window of growth phase, and in response upregulate expression of genes involved in the uptake and processing of extracellular DNA. Sporulation, second QS-controlled phenotype, occurs under extreme stress and nutritional scarcity. Prolonged nutrient deprivation compels the cell to enter the process of sporulation, the outcome of which is the production of a metabolically dormant endospore that resumes growth once the conditions become favorable again. Spore formation is a complex and tightly regulated phenomenon, where several hundred genes are directly and indirectly involved. Regulation of competence and sporulation is a complex and temporally regulated process. In present chapter, we will discuss QS driven regulation of competence and sporulation in different Gram-positive bacteria.