Bacterial communities associated with food-grade winter pea cultivars grown in Pacific Northwest soils

Authors: Yurgel, Svetlana; McGee, Rebecca

Submitted to: Microbial Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2025
Publication Date: 3/11/2025
Citation: Yurgel, S., Mcgee, R.J. 2025. Bacterial communities associated with food-grade winter pea cultivars grown in Pacific Northwest soils. Microbial Biotechnology. 2025:1-19. https://doi.org/10.1007/s11104-025-07316-7.
DOI: https://doi.org/10.1007/s11104-025-07316-7

Interpretive Summary: Autumn-sown food-grade winter pea (WP) varieties represent an exciting new crop for growers in the Pacific Northwest. Similar to other legumes, WP can establish mutually beneficial relationships (symbiosis) with soil bacteria (rhizobia) that convert atmospheric nitrogen to nitrogen fertilizer that is used by the legume and subsequent rotation crops. Development of new food-grade WP cultivars must be supported by improved understanding of their symbiotic potential and identification of rhizobia that can establish effective Nitrogen -fixing symbiosis. However, little is known about the ability of these new cultivars to establish symbiosis with rhizobia native to Pacific Northwest soils. In this study we evaluated microbial communities associated with three new food-grade WP cultivars grown in three diverse locations across Washington state (WA) with the goal of assessing WP symbiotic potential and identifying native bacteria capable of establishing symbioses with these plants. Our results indicate that a diverse population of native bacteria can colonize WP roots cultivated in WA soils. However, a substantially smaller subset of these bacteria can establish nitrogen-fixing symbiosis with the plant. We identified three dominant rhizobia capable of establishing symbiosis with WP. However, these rhizobia were not abundant in the soils, indicating their strong attraction to WP roots. These newly identified rhizobia might provide a valuable foundation for developing new WP inoculums to improveme sustainable pulse crop production.

Technical Abstract: Autumn-sown food-grade winter pea (WP) varieties represent an exciting new crop for growers in the Pacific Northwest. However, little is known about the ability of these new cultivars to establish symbiotic associations with rhizobia native to Pacific Northwest soils. In this study we evaluated bacterial root and nodule microbiomes associated with three new food-grade WP cultivars grown in three diverse locations across Washington state (WA) with the goal to assess the WP symbiotic potential, survey native rhizobia capable of establishing N-fixing symbioses with these plants and identify non-rhizobial nodule residents with the potential to be part of bacteria-legume symbiotic interaction. Our data indicate that a diverse population of native rhizobia can colonize WP roots cultivated in WA soils. However, a substantially smaller subset of these bacteria can colonize WP nodules. Interestingly, three rhizobial ASVs were dominant nodule residents in all tested locations regardless of the significant variation in soil microbiome diversity and structure between locations. These ASVs had relatively low abundance in the soils, indicating their strong attraction to host-plant roots and high competitiveness for nodulation. Our data emphasize the potential role of Pseudomonas in rhizobium-legume symbiosis. However, an in-depth study of legume root and nodule microbiome is required to better understand Rhizobium-legume-Pseudomonas symbiotic interaction.