The Pseudomonas fluorescens transcription activator AdnA is required for adhesion and motility

The locations of two mutations that prevent adhesion of Pseudomonas fluores cens Pf0-1 to sand columns and seeds (adn, adhesion) were identified. Both lie in a single gene showing homology to the NtrC/NifA family of transcript ion activators. The predicted 55 kDa protein encoded by adnA is most closel y related to activators involved in expression of flagellar proteins, consi stent with the lack of flagella in adnA strains. Constitutive adnA expressi on restored motility and adhesion to an adnA strain, demonstrating that the observed phenotypes are due to lack of AdnA and not a consequence of other mutations or polar effects of mutations in adnA on other genes.