Glucolipids and lipoteichoic acids affect the activity of SigI, an alternative sigma factor, and WalKR, an essential two-component system, in Bacillus subtilis.

In a Bacillus subtilis ugtP mutant lacking glucolipids, SigI was activated in the log phase, and the activation of SigI in the mutant was suppressed by the expression of native ugtP. By contrast, SigI was inhibited in a yfnI mutant lacking one of the lipoteichoic acid (LTA) synthase genes, and the inhibition was suppressed by the expression of yfnI. A series of mutation analyses of the sigI promoter revealed that the two WalR binding sites were involved in the increase of P -lacZ activity in the ugtP mutant and decrease of the lacZ activity in the yfnI mutant.