摘要Aquaporins are important transmembrane water transport proteins which transport water and sev-eral neutral molecules.However,how aquaporins are involved in the synergistic transport of Mg2+and water remains poorly understood.Here,we found that the cassava aquaporin MePIP2;7 was involved in Mg2+transport through interaction with MeMGT9,a lower affinity magnesium transporter protein.Knockdown of MePIP2;7 in cassava led to magnesium deficiency in basal mature leaves with chlorosis and necrotic spots on their edges and starch over-accumulation.Mg2+content was sig-nificantly decreased in leaves and roots of MePIP2;7-RNA interference(PIP-Ri)plants grown in both field and Mg2+-free hydroponic solution.Xen-opus oocyte injection analysis verified that MePIP2;7 possessed the ability to transport water only and MeMGT9 was responsible for Mg2+efflux.More importantly,MePIP2;7 improved the trans-portability of Mg2+via MeMGT9 as verified using the CM66 mutant complementation assay and Xenopus oocytes expressing system.Yeast two-hybrid,bimolecular fluorescence complementation,co-localization,and co-immunoprecipitation assays demonstrated the direct protein-protein interaction between MePIP2;7 and MeMGT9 in vivo.Mg2+flux was significantly elevated in MePIP2;7-overexpressing lines in hydroponic solution through non-invasive micro-test technique analysis.Under Mg2+-free condition,the retarded growth of PIP-Ri transgenic plants could be recovered with Mg2+supplementation.Taken together,our results dem-onstrated the synergistic effect of the MePIP2;7 and MeMGT9 interaction in regulating water and Mg2+absorption and transport in cassava.