The phosphodiesterase RmcA contributes to the adaptation of Pseudomonas putida to l-arginine

A new connection between the amino acid arginine and the modulation of the biofilm lifestyle of P. putida.Amino acids are crucial in nitrogen cycling and to shape the metabolism of microorganisms. Among them, arginine is a versatile molecule able to sustain nitrogen, carbon, and even ATP supply and to regulate multicellular behaviors such as biofilm formation. Arginine modulates the intracellular levels of 3 & PRIME;-5 & PRIME;cyclic diguanylic acid (c-di-GMP), a second messenger that controls biofilm formation, maintenance and dispersion. In Pseudomonas putida, KT2440, a versatile microorganism with wide biotechnological applications, modulation of c-di-GMP levels by arginine requires the transcriptional regulator ArgR, but the connections between arginine metabolism and c-di-GMP are not fully characterized. It has been recently demonstrated that arginine can be perceived by the opportunistic human pathogen Pseudomonas aeruginosa through the transducer RmcA protein (Redox regulator of c-di-GMP), which can directly decrease c-di-GMP levels and possibly affect biofilm architecture. A RmcA homolog is present in P. putida, but its function and involvement in arginine perceiving or biofilm life cycle had not been studied. Here, we present a preliminary characterization of the RmcA-dependent response to arginine in P. putida in modulating biofilm formation, c-di-GMP levels, and energy metabolism. This work contributes to further understanding the molecular mechanisms linking biofilm homeostasis and environmental adaptation.