Definition and evolution of a new symbiovar, sv. rigiduloides, among Ensifer meliloti efficiently nodulating Medicago species.

摘要: Abstract Understanding functional diversity is one of the main goals microbial ecology, and definition new bacterial ecotypes contributes significantly to this objective. Nitrogen-fixing bacteria provide a good system for investigation ecotypes/biovars/symbiovars, as they present different specific associations with several host plants. This symbiosis reflected both in nodulation fixation efficiency genetic characters bacteria, biovars have already been described species Ensifer meliloti. In study, affiliation E. meliloti strains trapped from nodules sampled Medicago rigiduloides roots was analyzed using housekeeping recA genes DNA–DNA hybridization. The these isolates also investigated symbiotic markers: (nodA, nodB, nodC) nitrogen (nifH) genes, well performance phenotypic tests capacity efficiency. These analyses led proposal symbiovar, sv. rigiduloides, that fixed efficiently on M. but not truncatula. Using phylogenetic reconstructions, including symbiovars, hypotheses lateral gene transfer loss are proposed explain emergence symbiovars within species. widespread geographical distribution symbiovar around Mediterranean Basin, contrast restriction Eastern European countries, suggests might be associated other plant description confirms need accurate ecological classification, especially analysis populations.