The Wsp intermembrane complex mediates metabolic control of the swim-attach decision of Pseudomonas putida

Pseudomonas putida KT2440, a microorganism of interest for biotechnological purposes, is one amongst the many bacteria that attach to surfaces and produce biofilm. Although other mechanisms that contribute to this decision have been studied until now, a 7-genes-operon with a disposition and homology shared with the wsp operon in Pseudomonas aeruginosa remained to be investigated. In this work, we characterized the function of P. putida wsp operon by the combination of deletion mutants with complementations with P. aeruginosa genes and with deletions of 3 other genes: the genes that code for the transcription factors fleQ and fleN and the flagellar movement regulator, fglZ. Examining mutant behaviour at 6 and 24 hours under three different carbon regimes (citrate, glucose and fructose) we saw that this complex carries out a similar function in both Pseudomonas. In P. putida, the key components are WspR, a protein that harbours the domain for producing c-di-GMP, and WspF, which controls its activity. Transformation with the equivalent proteins of P. aeruginosa had a significant impact on of P. putida mutant phenotypes and could complement their functions under some conditions. These results contribute to the deeper understanding of the complex element network that regulate lifestyle decision in P. putida.