In its natural environment Bacillus subtilis is often exposed to life-threatening and fluctuating conditions. To respond to these environmental changes B. subtilis use alternative σ-factors which activate gene clusters to help to adapt to the given conditions. Perceiving these environmental changes is often facilitated by membrane-associated proteins. One notable protein complex is the PspA-YdjGHI complex, which encodes the SPFH (Stomatin/Prohibitin/Flotillin/HflK-C) protein, YdjI (1). Members of the widely conserved SPFH family are associated with regulation of membrane fluidity (2,3) and are known for their impact on a variety of membrane bound processes, including developmental processes in B. subtilis (4,5). Here, we show that YdjI is required for efficient motility and development of social communities. Absence of ydjI in a biofilm leads to changes in metabolism associated genes clusters, indicating that cells within the biofilm are starving. This results in a decreased secretion of BslA, one of the major matrix genes, preventing the formation of the hydrophobic coat and rendering the biofilm surface hydrophilic. Interestingly, phenotypic complementation is only achieved in a background strain that renders YdjI cytosolic suggesting that YdjI has dual functions depending on its subcellular localisation.

(1) Savietto Scholz, A., et al. (2021) Front. Microbiol. 12: 754924

(2) Bach, J.N. et al. (2013) Mol. Micro. 88:1205-1217

(3) Zielińska, A., et al. (2020) Elife 9:e57179

(4) Yepes A, et al. (2012) Mol Microbiol. 86(2):457-471

(5) Dempwolff F, et al. (2012) J Bacteriol. 194(17):4652-61