Abstract: Strains of Pseudomonas have been genetically engineered to have enhanced biocontrol properties. The strains of the invention are particularly effective against plant pathogenic fungi such as species of Rhizoctonia and Pythium, because the strains produce enhanced amounts of antifungal metabolites such as pyrrolnitrin that are active against these fungal pathogens. Both the genetically modified biocontrol strains and the antifungal metabolites can be used as active agents for biocontrol compositions.

Abstract: The present invention is directed to the production of a polyketide antibiotic such as soraphen in a host via recombinant expression of the polypeptides needed to biologically synthesize the polyketide antibiotic. Polyketide synthase (PKS) genes encoding polypeptides necessary to synthesize soraphen are provided, along with methods for identifying and isolating the PKS genes needed to recombinantly biosynthesize any desired polyketide antibiotic. The cloned PKS genes may be transformed and expressed in a desired host organisms to produce soraphen for a variety of purposes, including protecting the host from a pathogen, developing the host as a biocontrol agent, and producing large, uniform amounts of soraphen.