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Activity of the B acillus thuringiensis NprR – NprX cell–cell communication system is co‐ordinated to the physiological stage through a complex transcriptional regulation
Author(s) -
Dubois Thomas,
Perchat Stéphane,
Verplaetse Emilie,
Gominet Myriam,
Lemy Christelle,
AumontNicaise Magali,
Grenha Rosa,
Nessler Sylvie,
Lereclus Didier
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12168
Subject(s) - biology , quorum sensing , transcription (linguistics) , repressor , promoter , transcription factor , microbiology and biotechnology , gene , genetics , gene expression , virulence , linguistics , philosophy
Summary NprR is a quorum sensor of the RNPP family found in bacteria of the B acillus cereus group. In association with its cognate peptide NprX , NprR controls the expression of genes essential for survival and sporulation of B acillus thuringiensis during its necrotrophic development in insects. Here, we report that the nprR – nprX genes are not autoregulated and are co‐transcribed from a σ A ‐dependent promoter ( P A ) located upstream from nprR . The transcription from P A starts at the onset of the stationary phase and is controlled by two transcriptional regulators: CodY and PlcR . The nutritional repressor CodY represses nprR – nprX transcription during the exponential growth phase and the quorum sensor PlcR activates nprR – nprX transcription at the onset of stationary phase. We show that nprX is also transcribed independently of nprR from two promoters, P H and P E , dependent on the sporulation‐specific sigma factors, σ H and σ E respectively. Both promoters ensure nprX transcription during late stationary phase while transcription from P A has decreased. These results show that the activity of the NprR – NprX quorum sensing system is tightly co‐ordinated to the physiological stage throughout the developmental process of the B acillus .