Plant growth depends on the continuous availability of the macro-nutrient phosphate(Pi).However,in most soils,Pi is only poorly accessible to plants,resulting in Pi deficiency and triggering a number of Pi starvation responses.One strategy of plants to over-come Pi limitation is to form a symbiosis with arbuscular mycor-rhizal(AM)fungi(Smith et al.,2011),which occurs with approximately 80％of land plants.AM fungi improve the uptake of Pi and other mineral nutrients and thereby increase plant performance and stress tolerance.They collect these minerals with an extraradical hyphal network from the soil and release them from highly branched structures,called arbuscules,into root cortex cells.Interestingly,Pi sufficiency causes inhibition of internal root colonization(Balzergue et al.,2011;Breuillin et al.,2010).The mechanistic basis for this has long remained obscure.Two studies have now solved this long-standing mystery and demonstrated that a canonical Pi-response regulatory module regulates AM symbiosis in accordance with the plant Pi status(Shi et al.,2021;Das et al.,2022).