Fast-growing rhizobia often contain one or more large indigenous plasmids. One of these plasmids,called pSym, carries the nodulation and nitrogen fixation genes necessary for establishing the Rhizobium-legume symbiosis; the other plasmids called non-pSym. In general, rhizobial indigenous plasmids show high stability. Rhizobial indigenous plasmids can be transferred among rhizobia species, to Agrobacterium, and also to other soil bacteria. Recombination may happen in the course of transferring and replication of rhizobial plasmid. Advance on the function of rhizobial symbiotic and nonsymbiotic ...
