SBIR Phase II: Natural biocides for treating bacterial pathogens in pome fruits and vegetable crops

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project will be the development of a new natural means of treating diseases of fruit orchards and crops as an alternative to antibiotic use. Over 90% of the world's antibiotic use in agriculture is primarily to control fire blight, a disease that kills fruit trees. Fire blight has emerged as the most devastating disease of apple and pear trees worldwide. Growers apply streptomycin or oxytetracycline multiple times during bloom and following plant injuries to prevent the growth of the causative agent of fire blight, Erwinia amylovora (Ea). Resistant Ea strains have been isolated, and are expected to impact the human food chain. The proposed technology will replace these antibiotics with the microscopic predators of bacteria, slime molds, which are benign to humans, animals, and plants. These bacterial predators represent a new proprietary biocontrol approach. The proposed project will focus on reducing orchard carriage of Ea, and the general approach should be extensible to treating agricultural infections of other species of bacterial pathogens. Ultimately, this innovation will contribute to increased public health by providing safer alternatives to existing antibiotics and disinfectants. This Small Business Innovation Research Phase II Project proposes a novel approach to treating fire blight, a pathogenic disease affecting pome fruits caused by E. amylovora, and tomato canker caused by C. michiganensis. Both pathogens form biofilms connected to their virulence in plants. There is currently no treatment although the incidence of reoccurring infections by E. amylovora and C. michiganensis contribute to millions of dollars of losses in fruit production. Antibiotics and disinfectants typically kill only growing cells. This approach consumes growing, dormant, or biofilm-enmeshed bacteria. Inclusion of biofilms as targets will help to identify a means to solve some of the most intractable infections known. The research objectives of this Phase II SBIR proposal are to: 1) Screen Dictyostelid (Dicty) isolates in vitro for biocontrol capabilities for orchards and decontamination of plants/equipment, 2) test efficacy of Dicty candidates en planta, and 3) design methods for spore production and packaging. For commercial applications, the goal is to use probiotic bacteria to amplify Dicty and produce spores. For spore preservation and dispersal, the plan is to use methods proven to be successful and safe for other biocides. Natural biocides products will be developed for agricultural research and to treat pathogenic outbreaks in fruit and vegetable crops.