How rice coordinates signals to partner with beneficial soil fungi

Most plants do not gather nutrients from the soil entirely on their own. Many form partnerships with microscopic fungi that grow inside their roots and extend into the surrounding soil. These partnerships, known as arbuscular mycorrhizal symbioses, help plants access nutrients, especially phosphorus. In return, the fungi receive carbon-rich compounds from the plants. But how does a plant coordinate the many signals needed to build and maintain this exchange?