Genetic diversity of rhizobia isolated from Astragalus adsurgens growing in different geographical regions of China

The genetic diversity among 95 isolates from Astragalus adsurgens was inves tigated using molecular biological methods. All of the isolates and 24 refe rence strains could be differentiated by AFLP, REP-, ERIC- and BOX-PCR fing erprinting analysis. By cluster analysis of the data, 31 AFLP and 38 Rep-PC R genomic groups were delineated, indicating considerable genetic diversity among the isolates. Fifty-four representative strains were further analyze d by RFLP of PCR-amplified 16S and 23S rDNA, revealing 26 rDNA genotypes am ong the isolates. The phylogenetic relationship of the isolates was. determ ined by partial sequencing of 16S rRNA genes of 16 strains. The results sug gest that the A. adsurgens rhizobia belong to the genera Agrobacterium, Mes orhizobium, Rhizobium and Sinorhizobium. (C) 2001 Elsevier Science B.V. All rights reserved.