Using the USDA Host/Fungus Database to classify potential pathogens impacting fall-sown winter peas

Authors: Porter, Lyndon; Yurgel, Svetlana

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2025
Publication Date: 10/1/2025
Citation: Porter, L.D., Yurgel, S. 2025. Using the USDA Host/Fungus Database to classify potential pathogens impacting fall-sown winter peas. American Phytopathological Society Abstracts. https://www.apsnet.org/meetings/annual/meetingarchives/PH2025/Rewind/Posters/3094092-P-231.pdf.

Interpretive Summary: Edible winter peas were approved for production in the US in 2009. Determining the root-rotting pathogens limiting winter pea production is critical to developing management practices that can successfully improve yields and reduce growers' risks. This research genetically characterized fungi associated with soil, roots and nodules of winter peas. Upon identifying the different fungi involved, a database developed by USDA-ARS scientist was used to characterize the potential ability of these fungi to act as a: 1) pea pathogen, 2) non-pea, legume pathogen, 3) non-legume pathogen and 4) non-pathogen. Classifying the pathogens into these categories, while combining additional genetic data determining the prevalence of a specific fungus in the soil, roots or nodules, helps to pinpoint fungi that may be acting as major root-rotting pathogens on winter peas that can be further researched to understand their impact on production and potential disease management practices to control them.

Technical Abstract: Winter peas for human consumption are a relatively new US crop since 2009. Because this crop experiences different environmental growing conditions than spring-sown peas, root rot pathogen complexes may differ. Determining fungi involved in root rot complexes in this production system is critical to optimizing management practices to control them. The objectives of this research were to identify fungi associated with the soil, roots and nodules of winter pea in Washington State to better understand the root rot complexes. Four winter pea cultivars were planted in two locations in Washington State and the soil, roots and nodules were sampled. Associated fungi from samples were identified using an Illumina MiSeq platform using short reads from the internal transcribe spacer 2 gene. A total of 217, 161, and 127 different fungal genera were identified in the soil, roots and nodules, respectively, across locations. Potential pathogenicity of these genera was characterized using the United States Department of Agriculture Host/Fungus Database (USDAHFD) containing over 800,000 fungus/host records. Using these records, genera were classified as: 1) pathogenic to pea, 2) non-pathogenic to pea but pathogenic to other Fabaceae species; 3) pathogenic to non-Fabaceae species and 4) non-pathogenic. Utilizing the USDAHFD to classify fungal taxa according to pathogenicity, combined with relative abundance data of genera, can facilitate identification of major fungi potentially contributing to winter pea root rot complexes and development of improved management strategies.