BSCL2 and infection: Overall, the current study extends our previous work [24] by providing new insights into the mechanisms of c-di-GMP-driven host adaptation in symbioses beyond infection and demonstrates the specific role of pelD that acts downstream of c-di-GMP to mediate the competitive fitness of Pseudomonas lurida MYb11 within its nematode host Caenorhabditis elegans MY316.