Fatty acids in arbuscular mycorrhizal fungi are synthesized by the host plant ($)

In the symbiotic relationship between arbuscular mycorrhizal fungi and plants, the fungal partner greatly enhances the uptake of mineral nutrients (particularly phosphate), while in return it is supplied with organic carbon from the photosynthetic partner. Luginbuehl et al. investigated whether this organic carbon is exchanged solely as sugars, or whether fatty acids are also transferred from plant to fungus. Using the ram1 mutant of Medicago truncatula (RAM1 encodes a transcription factor with targets including genes involved in fatty acid biosynthesis), fatty acid synthesis mutants of the symbiotic fungus, and two-compartment systems with shared fungal hyphal networks, the authors were able to show that lipids are a major source of organic carbon delivered to the fungus. Science 10.1126/science.aan0081 You can also read a new review on this same topic by Rich et al. Trends Plant Sci. 10.1016/j.tplants.2017.05.008