Interactions of Arbuscular Mycorrhiza and Nitrogen-Fixing Symbiosis in Sustainable Agriculture

The great agricultural and environmental importance of legumes, plus the ability of their rhizosphere system is able to harbour symbionts and other associated microbes of great relevance to plant productivity, make legumes target crops in sustainable agriculture. Current developments in the ecology, physiology, biochemistry, molecular biology, and biotechnology of microbe-plant relationships have given new insights into understanding the formation and functioning of the tripartite arbuscular-mycorrhizal and nitrogen-fixing symbioses of legumes and their interactions with PGPR. Although the technology for the production of rhizobial and free-living PGPR is commercially available, the production of AM fungi inocula and the development of inoculation techniques have limited the manipulation of AM fungi. However, current biotechnology practices now allow the production of efficient AM-fungal inoculants. Therefore, an appropriate management of selected AM fungi, rhizobia, and PGPR is now an available technique for exploiting the benefits of these microorganisms in agriculture, horticulture, and in revegetation of degraded ecosystems.