Common and Host Specific Nodulation Genes in Rhizobium Meliloti and Their Conservation in Other Rhizobia

Abstract

Recognition of the appropiate legume host and nodule induction are controlled by two sets of Rhizobium genes, common nodulation (nod) and host-specific nodulation (hsn) genes. These genes have been identified in several Rhizobium species, including R.meliloti, the symbiotic partner of alfalfa (Medicago). Here we present our studies on the organization and regulation of R.meliloti nodulation genes. Moreover, these genes were used to identify and analyse genes of similar function in other rhizobia which may help us to elucidate the basis of host-specificity of Rhizobium-legume interaction and the genetic control of these processes.