Adaptive and progressive evolution of plant-microbial symbiosis

Abstract

In the N2-fixing symbionts of legumes (rhizobia), the evolution of (altruistic) characters that are useful for a host occurs in the populations colonizing the subscellular compartments of nodules (infection threads, symbiosomes). These compartments appear as a result of the coevolution of partners, which is associated with the complication of the trophic and regulatory interactions determining the ecological efficiency of symbiosis. Their analysis allows us to study the correlation of the mechanisms of the adaptive and progressive evolution of symbiosis, which is still unclear for free-living organisms.