Symbiotic microorganisms improve nutrient uptake by plants.To initiate mutualistic symbiosis with arbus-cular mycorrhizal(AM)fungi,plants perceive Myc factors,including lipochitooligosaccharides(LCOs)and short-chain chitooligosaccharides(CO4/CO5),secreted by AM fungi.However,the molecular mechanism of Myc factor perception remains elusive.In this study,we identified a heteromer of LysM receptor-like kinases consisting of OsMYR1/OsLYK2 and OsCERK1 that mediates the perception of AM fungi in rice.CO4 directly binds to OsMYR1,promoting the dimerization and phosphorylation of this receptor complex.Compared with control plants,Osmyr1 and Oscerk1 mutant rice plants are less sensitive to Myc factors and show decreased AM colonization.We engineered transgenic rice by expressing chimeric receptors that respectively replaced the ectodomains of OsMYR1 and OsCERK1 with those from the homologous Nod factor receptors MtNFP and MtL YK3 of Medicago truncatula.Transgenic plants displayed increased cal-cium oscillations in response to Nod factors compared with control rice.Our study provides significant mechanistic insights into AM symbiotic signal perception in rice.Expression of chimeric Nod/Myc recep-tors achieves a potentially important step toward generating cereals that host nitrogen-fixing bacteria.