Mycobiome Associated with Soil, Root and Nodules of Food-Quality Winter Peas in the Pacific Northwest, USA

Autumn-sown food-quality winter pea represent an exciting new crop for growers in the Pacific Northwest (PNW), USA. However, understanding interactions between this crop and fungi native to PNW soils is necessary to advance disease management. In this study, we applied ITS rRNA amplicon sequencing to evaluate fungal communities (mycobiomes) associated with soil, roots, and nodules of four winter pea cultivars in two locations in Washington state to identify putative pathogens in winter pea production systems. Data indicated plant genotype did not have a significant effect on bulk soil mycobiome but significantly affected root and nodule microbial communities. Multiple putative plant pathogenic taxa known to infect pea were identified. The abundance of some of these taxa differed in the soil, roots and nodules between locations. Regardless of the location, the root mycobiome was enriched with the plant pathogenic genus Thanatephorus. A significant positive correlation was detected between Podospora, Alternaria, Didymellaceae, and Cladosporium, and between Didymella and Thanatephorus, suggesting coexistence or potential synergistic interactions between these taxa within each group. The winter pea nodule mycobiome was overpopulated with Sclerotinia trifoliorum indicating potential susceptibility of nodule tissue to this pathogen. Additionally, genera Cryptococcus and Solicoccozyma were significantly enriched in the nodules, compared to the roots, suggesting a role of these psychrophilic fungi in symbiotic host/fungal interactions.