Full text loading...
Chapter 19 : Environmental Control of Cyclic Di-GMP Signaling in Pseudomonas fluorescens: from Signal to Output
Recently it was shown that Pi concentration regulates biofilm formation by Pseudomonas fluorescens Pf0-1 through a cyclic di-GMP (c-di-GMP) signaling pathway. Study of this response has produced one of the more complete pictures of how c-di-GMP signaling can link an environmental signal to a complex biological output. This research supports the idea that c-di-GMP is a conserved modality in biofilm regulation, with distinct outputs in different organisms, and provides a paradigm for conditional, transcriptional control of c-di-GMP signaling pathways. The cellular c-di-GMP levels in wild-type (WT) and the rapA mutant were compared under Pi starvation conditions. While LapA was secreted by lapD mutants, it was not retained in the cell-associated protein fraction and was lost to the culture supernatant. This phenomenon is notably similar to what happens to LapA in these fractions when the WT is grown in low Pi, prompting investigation of LapD’s role in Pho regulon control of LapA localization, discussed. LapD and RapA both affect LapA localization to the cell surface, and lapD was required for biofilm formation by the pstrapA mutant. The description above represents the current extent of our knowledge about c-di-GMP signaling in Pseudomonas fluorescens strain Pf0-1. The Wsp chemosensory pathway regulates adherence and EPS production by P. fluorescens strain SBW25 and Pseudomonas aeruginosa PA01. Transcriptional regulation of RapA in P. fluorescens Pf0-1 seems a relatively straightforward strategy for modulating c-di-GMP levels when compared to other mechanisms shown to regulate DGC and PDE activities, including allosteric activation, subcellular localization, and mRNA stability.
Key Concept Ranking
- Pseudomonas fluorescens