Diversity and Geographic Distribution of Microsymbionts Associated With Invasive Species in Southern China.

In order to investigated diversity and geographic distribitution of rhizobia associated with invasive species, nodules and soils around the plants were sampled from five provinces in southern China. In total, 361 isolates were obtained from and in 25 locations. A multi-locus sequence analysis (MLSA) including 16S rRNA, , , , , and identified the isolates into eight genospecies corresponding to , , , , sp., , , and . The majority of the isolates were (62.6%), followed by (33.5%) and (2.9%). strains were more predominant in nodules of (76.2) than in (59.9%), and the distribution of in those two plant species was reverse (3.4:18.2%). Four symbiotypes were defined among the isolates based upon the phylogeny of - genes, represented by , -, spp., and spp. The species affiliation and the symbiotype division among the isolates demonstrated the multiple origins of rhizobia in China: most were similar to those found in the original centers of plants, but sp. might have a local origin. The unbalanced distribution of symbionts between the two species might be related to the soil pH, organic matter and available nitrogen; spp. generally dominated most of the soils colonized by in this study, but it had a particular preference for neutral-alkaline soils with low fertility whereas. While spp. preferred more acidic and fertile soils. The spp. tended to prefer neutral-acidic soils with high fertility soils.