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

In this study we evaluated bacterial root and nodule microbiomes associated with three new food-grade WP cultivars and one more genetically distant WP genotype 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 Amplicon Sequence Variants 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 indicate that Pseudomonas was apparently enriched in the summer-collected nodules compared to roots. However, an in-depth study of legume root and nodule microbiome is required to better understand Rhizobium-legume-Pseudomonas symbiotic interaction.