Comparative analysis of structural organization of the genome in alfalfa nodule bacteria Sinorhizobium medicae and Sinorhizobium meliloti

摘要

The plasmid composition and restriction fragment length polymorphism (RFLP) of Sinorhizobium medicae strains, isolated from annual lucerne (Medicago) and the perennials Melilotus and Trigonella from various geographic localities, and S. meliloti reference strains were analysed. Lucerne nodule bacteria of species S. medicae and S. meliloti showed no significant differences in plasmid composition and structure of the nodD1 nodABC common virulence genes. However, S. medicae strains differed from S. meliloti in structure of the locus containing the recA and nifKDH genes. A structural difference in the locus containing the nodD2 gene and a cluster of the 19 exo genes, which are important in the interaction of nodule bacteria with plants, was assumed tobe of special interest.