The production of the compound 2-hexyl-5-propyl resorcinol (HPR) by the biocontrol
rhizobacterium Pseudomonas chlororaphis PCL1606 (PcPCL1606) is crucial for fungal
antagonism and biocontrol activity that protects plants against the phytopathogenic
fungus Rosellinia necatrix. The production of HPR is also involved in avocado root
colonization during the biocontrol process. This pleiotrophic response prompted us
to study the potential role of HPR production in biofilm formation. The swimming
motility of PcPLL1606 is enhanced by the disruption of HPR production. Mutants
impaired in HPR production, revealed that adhesion, colony morphology, and typical
air–liquid interphase pellicles were all dependent on HPR production. The role of HPR
production in biofilm architecture was also analyzed in flow chamber experiments.
These experiments revealed that the HPR mutant cells had less tight unions than
those producing HPR, suggesting an involvement of HPR in the production of the
biofilm matrix.
