Adaptive and progressive evolution of plant-microbe symbiosis

Abstract

In N2-fixing symbionts of leguminous plants (rhizobia) evolution of the host-beneficial (“altruistic”) traits occurs in populations colonizing the subcellular compartments in nodules (infection threads, symbiosomes). These compartments are developed as a result of partners’ coevolution related to complications of trophic and regulatory interactions elevating the ecological efficiency of symbiosis. Their analysis enables us to study correlations between genetic mechanisms of adaptive and progressive symbiosis evolution which remain obscure in free-living organisms