Agricultural productivity depends on supplying crops with adequate nutrients. To that end there is interest in using an ancient plant symbiosis with fungi to improve the ability of crops to absorb nutrients from the soil. Found in most plants, the symbiosis is formed when select soil fungi invade plant root cells, using plant lipids and sugars to proliferate without harming the plant. The fungal cells reward the plant’s hospitality by sending hyphae out into the soil and absorbing nutrients such as nitrogen and phosphate, transporting them back into the root and providing them to the plant. Because the fungus mimics the function of plant roots the symbiosis is known as mycorrhiza (“fungal roots”). A number of startup companies are centered on developing fungal inoculum that lead to the development of crop mycorrhizal symbioses.