A histidine-kinase cheA gene of Pseudomonas pseudoalcaligens KF707 not only has a key role in chemotaxis but also affects biofilm formation and cell metabolism

A histidine-kinase cheA gene in Pseudomonas pseudoalcaligenes KF707 plays a central role in the regulation of metabolic responses as well as in chemotaxis. Non-chemotactic mutants harboring insertions into the cheA gene were screened for their ability to form biofilms in the Calgary biofilm device. Notably, ≥95% decrease in the number of cells attached to the polystyrene surface was observed in cheA mutants compared to the KF707 wild-type biofilm phenotype. The ability to form mature biofilms was restored to wild-type levels, providing functional copies of the KF707 cheA gene to the mutants. In addition, phenotype micro-arrays and proteomic analyses revealed that several basic metabolic activities and a few periplasmic binding proteins of cheA mutant cells differed compared to those of wild-type cells. These results are interpreted as evidence of a strong integration between chemotactic and metabolic pathways in the process of biofilm development by P. pseudoalcaligenes KF707.