RT Journal Article SR Electronic T1 The ColR/S two-component system is a conserved determinant of host association across Pseudomonas species JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.12.14.472530 DO 10.1101/2021.12.14.472530 A1 Wiesmann, Christina L. A1 Zhang, Yue A1 Alford, Morgan A1 Thoms, David A1 Dostert, Melanie A1 Wilson, Andrew A1 Pletzer, Daniel A1 Hancock, Robert E. W. A1 Haney, Cara H. YR 2021 UL http://biorxiv.org/content/early/2021/12/15/2021.12.14.472530.abstract AB Members of the bacterial genus Pseudomonas form mutualistic, commensal and pathogenic associations with diverse hosts. The prevalence of host association across the genus suggests that symbiosis may be a conserved ancestral trait and that distinct symbiotic lifestyles may be more recently evolved. Here we show that the ColR/S two-component system, part of the Pseudomonas core genome, is functionally conserved between Pseudomonas aeruginosa and Pseudomonas fluorescens. Using plant rhizosphere colonization and virulence in a murine abscess model, we show that colR is required for commensalism with plants and virulence in animals. Comparative transcriptomics revealed that the ColR regulon has diverged between P. aeruginosa and P. fluorescens and deleting components of the ColR regulon revealed strain-specific, but not hostspecific, requirements for ColR-dependent genes. Collectively, our results suggest that ColR/S allows Pseudomonas to sense and respond to a host, but that the ColR-regulon has diverged between Pseudomonas strains with distinct lifestyles.Competing Interest StatementThe authors have declared no competing interest.