Abstract
Summary The general stress response and the decision‐making processes of sporulation initiation are interconnected pathways in the regulatory network of Bacillus subtilis . In a previous study we provided evidence for a mechanism capable of impairing sporulation by σ B ‐dependent induction of spo0E , encoding a phosphatase specifically inactivating the sporulation master regulator Spo0A∼P. Here we show that the σ B promoter (Pσ B ) of spo0E is responsive to sub‐inhibitory levels of ethanol stress, producing a σ B ‐dependent sporulation deficient phenotype. In addition to positive regulation by σ B , we identified Rok, the repressor of comK , to be a direct repressor of spo0E expression from Pσ B . This constellation provides the possibility to integrate signals negatively acting on sporulation initiation through the σ B branch as well as a positive feedback loop acting on Pσ B by Rok that is most likely a direct consequence of Spo0A∼P activity. Thus, the molecular mechanism described here offers the opportunity for cross‐talk between the general stress response and sporulation initiation in the adaptational gene expression network of B. subtilis .