FIG 10.

Summary of cdG-mediated regulation in S. meliloti. Black lines show regulatory interactions described in this study, and gray lines denote previously identified regulatory links (25, 34, 49, 50, 68, 69). Biosynthesis of QS signals is negatively regulated at the level of sinI transcription. EPS I and EPS II biosynthesis is affected by cdG via unknown pathways. Phosphate limitation-induced activation of EPS II biosynthesis is reduced at elevated cdG levels. This includes a change in wgeA promoter activity. Biofilm formation is enhanced involving gene products of the SMc01794-SMc01790 operon and is negatively affected by the global regulators MucR and ExpR, which also regulate motility and EPS biosynthesis. Flagella contribute to biofilm formation. Repression of swimming motility involves binding of cdG to the PilZ-domain protein McrA.