Interactions Between Rhizobium Meliloti and Rhizobium Trifolii Nodulation Genes: What is the Basis for Dominance by R. Meliloti?

Abstract

Host-specificity of Rhizobium nodulation is controlled, at least in part, by host-specific nodulation (HSN) genes. Several lines of evidence suggest that R. meliloti HSN genes are dominant to R. trifolii HSN genes. Introduction of a plasmid (pGMI149) encoding R. meliloti host-specific and common nod genes to R. trifolii confers alfalfa nodulation ability to R. trifolii 1,3. In contrast, introduction of a similar plasmid (pRt032) encoding R. trifolii common and host-specific nod genes to R. meliloti does not extend the host-range of R. meliloti 2. Here we report that introduction of R. meliloti HSN genes to R. trifolii strongly inhibits R. trifolii’s ability to nodulate clover. The work described below addresses two specific questions relating to this apparent dominance of R. meliloti HSN genes.KeywordsWhite CloverSubterranean CloverClover PlantNodulation AbilityRhizobium NodulationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.