Biofilm-Constructing Variants of Paraburkholderia phytofirmans PsJN Outcompete the Wild-Type Form in Free-Living and Static Conditions but Not In Planta

Paraburkholderia phytofirmans strain PsJN is a well-studied plant-associated bacterium known to induce resistance against biotic and abiotic stresses. In this work, we described the spontaneous appearance of mucoid variants in PsJN from static cultures. We showed that the conversion from the wild-type (WT) form to variants (V) correlates with an overproduction of EPS, an enhanced ability to form biofilmin vitro andin planta , and a reduced swimming motility. Our results revealed also that these phenotypes are in part associated with spontaneous mutations in an iron-sulfur cluster. Overall, the data provided here allow a better understanding of the adaptive mechanisms likely developed byP. phytofirmans PsJN in a heterogeneous environment.