Interaction between host and rhizobial strains: affinities and coevolution

? AGUILAR OM, BEKER MP, BLANCO FA, ZANETTI ME, CALDEROLI PA

Nitrogen Fixation

Wiley & Son

Año: 2015; p. 203 - 208

The legume‐rhizobia symbiosis is characterized by the formation of a new root organ, the nodule, in which bacteria fix atmospheric di‐nitrogen. In order to improve the growth of legume crops, the efficiency of nitrogen fixation has to be considered and the possibility to use elite rhizobial strains to overcome dominance of indigenous, less efficient, strains in an inoculation program.The perception of the nodulation factor by plant receptors explains some of the preferential nodulation by rhizobial strains and species. This opens biotechnological possibilities to target a key event that controls nodulation by specific strains whereas the knowledge that soybean plays control of nodulation by using plant resistance genes, suggests another strategy to be exploited. Other symbiotically active compounds yet unidentified appears to be important in determining host affinity beside the nodulation factor. Common bean is preferentially nodulated by Rhizobium etli from the same geographical region of host domestication. This compatibility that became established after coevolution between host and rhizobia in the same region can also be used to examine the basis of hostxrhizobium interactions.