Arginine Kinase Mcsb and Clpc Complex Impairs the Transition to Biofilm Formation in Bacillus Subtilis

Abstract

Robust biofilm formation on host niches facilitates beneficial Bacillus to promote plant growth and inhibit plant pathogens. Arginine kinase McsB is involved in bacterial development and stress response by phosphorylating proteins for degradation through a ClpC/ClpP protease. Conversely, cognate arginine phosphatase YwlE counteracts the process. Regulatory pathways of biofilm formation have been studied in Bacillus subtilis, but the roles of McsB, ClpC, and YwlE in biofilm formation remain unclear. In this study, we characterized that McsB and ClpC are negative regulators of biofilm formation and matrix gene eps expression. Our genetic and morphological evidence further indicates that McsB and ClpC inhibit eps expression by decreasing the spo0A and sinI expression, leading to the release of SinR, a known repressor of eps transcription. Given that the spo0A and sinI expression is under the control of Spo0A, we next demonstrate that McsB interacts with Spo0A directly by bacterial two-hybrid and glutathione-S-transferase pull-down experiments. Additionally, we present that McsB forms a complex with ClpC to dampen biofilm formation in vivo. Finally, we show that YwlE is a positive regulator of biofilm formation, counteracting the function of McsB. These findings suggest that McsB, ClpC, and YwlE play vital roles in the transition to biofilm formation in Bacillus subtilis, providing new insights into the regulatory mechanisms underlying biofilm development.

Keywords: Bacillus subtilis, Biofilm formation, McsB, ClpC, YwlE, Regulatory pathways