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

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.

本研究针对华盛顿州（WA）三个不同种植点位栽培的3个新型食用级WP品种与1个遗传亲缘关系更远的WP基因型，对其根部与根瘤的细菌微生物组展开评估，旨在明确WP的共生潜能，筛选可与该类植物建立固氮共生关系的土著根瘤菌，并挖掘具备参与细菌-豆科植物共生互作潜力的非根瘤菌类根定殖微生物。研究数据显示，土著根瘤菌的多样类群可定殖于华盛顿州土壤中栽培的WP根系，然而能够定殖WP根瘤的细菌类群仅占其中极小一部分。值得注意的是，无论各采样地点间土壤微生物组的多样性与结构存在显著差异，3个根瘤菌扩增子序列变异型（Amplicon Sequence Variants, ASVs）均为所有测试点位根瘤中的优势定殖类群。这些扩增子序列变异型在土壤中的丰度相对较低，表明其对宿主植物根系具有较强的趋性，且在结瘤竞争中具备高竞争力。数据还表明，相较于根系，夏季采集的根瘤中假单胞菌属（Pseudomonas）丰度显著富集。但为更深入解析根瘤菌-豆科植物-假单胞菌的共生互作机制，仍需针对豆科植物根系及根瘤微生物组开展更系统深入的研究。