P-175 - A novel candidate gene can be used for Phytophthora capsici species-level identification in a Recombinase Polymerase Amplification (RPA) Assay.

Cucurbit crops across the globe are devastated by Phytophthora blight caused by Phytophthora capsici, leading growers to experience heavy economic losses. On-farm surface irrigation sources harbor the pathogen propagules and can be a source of inoculum in each growing season. Water sanitation systems have high input and maintenance costs that hinder grower adoption of disinfection strategies. Recombinase Polymerase Amplification (RPA) is an isothermal amplification method that has successfully elucidated other Phytophthora species in plant samples. Developing an accessible, in-situ diagnostic tool for P. capsici detection is an invaluable tool for growers to determine if establishing sanitation technologies is needed to rid the irrigation sources of the pathogen. We have identified a novel species-specific marker for P. capsici detection, incorporated this marker into a fluorometric RPA assay, and tested for specificity against other related Phytophthora species and other unrelated, but likely present pathogens in North Carolina water sources. Establishing this P. capsici-specific RPA assay will be a valuable tool for growers to evaluate the cost-benefit of implementing on-farm water sanitation practices to reduce vegetable production losses.