Genotypic composition and performance of pea-nodulating rhizobia from soils outside the native plant-host range.

Cultivated soils need to shelter suitable rhizobia for legume cropping, especially in areas outside of the plant-host native range, where soils may lack efficient symbiotic partners. We analyzed the distribution patterns and traits of native rhizobia associated with L. in soils of Hebei Province, a region that has recently experienced an expansion of pea production in China. A total of 43 rhizobial isolates were obtained from root-nodules and characterized genetically and symbiotically. The isolates discriminated into 12 genotypes as defined by PCR-RFLP of IGS DNA. Multiple locus sequence analysis (MLSA) based on the 16S rRNA, , and of representative strains placed them into five clusters of four defined species (, , , and ) and a novel genospecies. was the dominant group (58%) followed by (23%). The other groups composed of (14%), (1 isolate) and the new genospecies (1 isolate), were minor and site-specific. Based on phylogeny, all representatives were intermingled within the symbiovar viciae with and being a new record. All the tested strains showed efficient symbiotic fixation on pea plants, with half of them exhibiting better plant biomass performance. This suggests that the pea-nodulating rhizobia in Hebei Province form a specific community of efficient symbiotic rhizobia on pea, distinct from those reported in other countries.