The effect of polyhydroxyalkanoates in PA23 biofilm formation, stress endurance, and interaction with the protozoan predator .

PA23 is a biocontrol agent capable of protecting canola against the fungal pathogen . In addition to producing antifungal compounds, this bacterium synthesizes and accumulates polyhydroxyalkanoate (PHA) polymers as carbon and energy storage compounds. Because the role of PHA in PA23 physiology is currently unknown, we investigated the impact of this polymer on stress resistance, adherence to surfaces, and interaction with the protozoan predator .

PA23 metabolites protect against protozoan grazing by the predator .

Background: strain PA23 is a biocontrol agent that is able to protect canola against the pathogenic fungus . This bacterium secretes a number of metabolites that contribute to fungal antagonism, including pyrrolnitrin (PRN), phenazine (PHZ), hydrogen cyanide (HCN) and degradative enzymes. In order to be successful, a biocontrol agent must be able to persist in the environment and avoid the threat of grazing predators.

Quorum sensing and the anaerobic regulator (ANR) control polyhydroxyalkanoate (PHA) production in Pseudomonas chlororaphis PA23.

Pseudomonas chlororaphis PA23 is a biocontrol agent that, in addition to producing antifungal compounds, synthesizes polyhydroxyalkanoate (PHA) polymers as a carbon and energy sink. Quorum sensing (QS) and the anaerobic regulator (ANR) are required for PA23-mediated fungal suppression; however, the role of these regulators in PHA production is unknown. Strains lacking either QS or ANR accumulated less PHA polymers when propagated on Ramsay's minimal medium (RMM) with glucose or octanoate as the carbon source.