Arbuscular mycorrhizas are ancient symbioses between fungi and plant roots that played a key role in the evolution of vascular land plants and remain a vital component of plant communities today. The mechanisms promoting bidirectional nutrient transfer of phosphates and sugar are beginning to be revealed and transport genes that are specifically expressed in the presence of the fungi have now been identified.
Smith, S., & Barker, S. (2002). Plant phosphate transporter genes help harness the nutritional benefits of arbuscular mycorrhizal symbiosis. Trends in Plant Science, 7(5), 189-190. https://doi.org/10.1016/S1360-1385(02)02260-4