SBIR-STTR Award

Bacterial plant diseases of economically important crops are difficult to control. Chemicals used to treat bacterial plant diseases cannot only alter soil flora and fauna, but are unreliable for preventive control when environmental conditions favor growth of plant pathogenic bacteria. This research is directed toward development of an effective control for bacterial plant diseases using phages which are specific for their bacterial hosts. Although the use of phages against bacterial plant pathogens has been proposed in the past, no commercial application has taken place. This was due largely to the development of mutant bacteria resistant to the controlling phage. Unlike past uses of a single phage for treatment, this method utilizes a mixture of phages including h- or host-range mutants. H-mutants, derived by spontaneous mutation of the wild-type parent phages, will attack and kill not only phageresistant mutants but also wild-type bacteria. It is proposed that mixtures of phages, containing hmutants, can be used effectively to control pathogenic bacteria which cause a variety of plant diseases as well as to control ice nucleation.Applications:It is anticipated that the effectiveness of h-mutant phage mixtures for control of bacterial plant diseases will be demonstrated against Xanthomonas campestris pv. vesicatoria, the causative agent of the destructive bacterial spot disease of tomato and pepper. Unlike chemicals, phage mixtures offer a reliable control alternative with no biological or environmental risk. Control of bacterial plant diseases is critical to ensure consistent high crop yields. Inasmuch as plant pathogenic bacteria and frost induction by certain plant-associated bacteria cause considerable crop damage and serious economic loss worldwide, an untapped market will be generated.

Bacterial plant diseases of economically important crops are difficult to control. Chemicals used to treat bacterial plant diseases not only alter soil flora and fauna, but are unreliable for preventive control when environmental conditions favor growth of plant pathogenic bacteria. Phase I research demonstrated the effectiveness of Mutant phage mixtures using Xanthomonas campestris pv. vesicatoria, the etiological agent of bacterial spot on tomato and pepper as the model system. The use of phages to control bacterial plant pathogens was proposed in the past, but no commercial application has taken place. This was due largely to the development of mutant bacteria resistant to the controlling phage. Unlike past uses of single phage for treatment, this process utilizes a mixture of phages including h- or host-range mutants. H-mutants, derived by spontaneous mutation of the wild-type parent phages, will attack and kill not only phage-resistant mutants but also wild-type bacteria. Phase n research will determine all factors to bring in-mutant phage technology to commercial production.Applications:Phase n research will define all parameters including dosage rates and methods of applications for using in-mutant phage mixtures to control several bacterial plant diseases such bacterial canker, speck, spot, and wilt of tomatoes as well as watermelon fruit blotch. It is anticipated that all parameters will be optimized for commercial application on an industrial scale under outdoor, uncontrolled conditions. Unlike chemicals, phage mixtures offer a reliable control alternative with no biological or environmental risk. Inasmuch as plant pathogenic bacteria and frost induction by certain plantassociated bacteria cause considerable crop damage and serious economic loss worldwide, an untapped market will be generated.