Potential for industrial application of microbes in symbioses that influence plant productivity and sustainability in agricultural, natural, or restored ecosystems

Microbes in three widespread and evolutionarily stable mutualistic symbioses with plants offer a range of nutritional and other benefits that may be modified or enhanced through selection or genetic manipulation for biotechnological applications. In this review, the biology, ecology, and genetics of arbuscular mycorrhizal fungi partnering with more than 80% of all land plant species; rhizobia bacteria that nodulate legumes and fix atmospheric nitrogen; and Epichloë fungi endophytic on cool-season grasses, are discussed. Research on these symbioses indicates considerable potential to utilize modified or natural microbial strains to stimulate production selectively of desirable compounds in plants or to introduce or over-express genes that can stimulate beneficial effects of the mutualisms on desirable traits in plant hosts, whether in agricultural or more natural ecosystems.