Fresh knowledge for an old relationship : new discoveries in molecular mycorrhizal research

At the end of July 2017, the foremost researchers in molecular mycorrhizal biology met together at the Natural History Museum of Toulouse to discuss new and cutting edge discoveries in this field. The meeting follows on from the success of the two previous meetings in Munich (2012) and Cambridge (2015). The days were packed with both scientific and social activity, including lovely lunches in the shade of the Toulouse botanical gardens, and a conference dinner cruising on the Garonne River (Fig. 1). Mycorrhizal associations have shaped land plants since their emergence and are one of the important drivers shaping ecosystem and agricultural health and productivity (van der Heijden et al., 2015; Martin et al., 2017). Both arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi colonize the roots of host plants where they receive plant-derived carbon (C) in exchange for supplying growth-limiting resources such as phosphorus (P) and nitrogen (N). They were first described c. 150 years ago, and, as Paola Bonfante (University of Torino, Italy) outlined in her keynote lecture, current mycorrhizal research stands on the capable shoulders of those who have gone before. Since then, advances in the field, and particularly in molecular, transcriptomic and genomic resources, have initiated an explosion of information on how this ancient and intimate association takes place. The great challenge to mycorrhizal researchers today is in taking the huge amount of information being generated and translating it into useful knowledge. From the stimulating talks at iMMM 2017, it is apparent that much excellent work is being done on furthering the understanding of both plant and fungal regulatory molecules in establishing symbiosis, how nutrient exchange and availability affects symbiotic outcomes and how genomic resources are defining the evolutionary path of the mycorrhizal life. I present here some highlights and main themes of discussion.