Within the plant ecological community of commensal, symbiotic and pathogenic microorganisms –– mutualistic fungal and bacterial symbionts are striking examples of microorganisms playing crucial roles in nutrient acquisition. They have co-evolved with their hosts since the initial plants’ adaptation to land (472-461 million years ago).
Despite the evolutionary distances that separate mycorrhizal (describing a fungus that grows in association with the roots of a plant in a symbiotic, or perhaps slightly pathogenic, relationship) and nitrogen-fixing plants (most notably legumes, in the family Fabaceae, such as alfalfa, beans, clover, cowpeas. lupines, peanut, soybean, and vetches), these symbiotic associations share a number of highly conserved features –– including specific plant symbiotic signaling pathways, root colonization strategies that circumvent plant immune responses, functional host-microbe interface formation, and the central role of phytohormones in symbiosis-associated root developmental pathways.
Authors [see attached article] highlight recent and emerging areas of investigation involving these evolutionarily conserved mechanisms, with an emphasis on the more ancestral mycorrhizal associations, and consider to what extent this knowledge can contribute to our understanding of plant-microbiota associations as a whole.
Science 20 May 2017; 356: 819 [1-page summary] plus 356, eaad4501 (2017) 26 May 2017 [whole article]