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TECHNICAL SESSION: Characterization of crop-associated microbiome

The influence of crop production practices, and temperature on the abundance of Pythium and Phytophthora in soybean
Krystel Navarro - The Ohio State University. Saranga Wijeratne- The Ohio State University, Anne Dorrance- The Ohio State University, Maria Soledad Benitez Ponce- Department of Plant Pathology, The Ohio State University

In Ohio, soil-borne diseases, especially those caused by Pythium and Phytophthora, can be a limiting factor for soybean production. Reproduction and infection are dependent on soil edaphic factors, soil moisture levels, and temperature. However, how these influence which species of Pythium and Phytophthora are favored is poorly understood. This study used an amplicon sequencing approach with oomycete specific primers (ITS6/ITS7) paired with direct isolation methods of soils baited at 15 and 25 ?C to determine which communities were favored in five research farm fields with different production practices over five years. Pythium and Phytophthora communities differed between fields where continuous soybean was grown compared to continuous corn and to those with a soybean, corn and wheat rotation. The species Pythium sylvaticum and Pythium ultimum were the most recovered species using direct isolation methods. These were also abundant when using amplicon sequencing. Additionally, based on OTU abundance, four different Pythium species were significantly more abundant at 15 ?C compared to 25 ?C. This study reports how oomycete communities are shaped based on agricultural practices and how the abundance of these species can change when exposed to different temperatures.