OsMATE16 Regulates Anther Dehiscence by Modulating IAA Content Under High Temperature

Rising global temperatures threaten rice yield, with the panicle stage being particularly sensitive to heat stress. Yet, the molecular mechanisms and key regulators underlying heat–induced reduction of seed setting remain largely unknown. We identified OsMATE16, a member of the multidrug and toxic compound extrusion (MATE) transporter family, as being significantly induced by heat stress. Knockout of OsMATE16 (OsMATE16-KO) mutants exhibited a pronounced reduction in seed setting rate compared with wild type plants, a phenotype that was further aggravated under heat stress. The OsMATE16-KO mutants displayed defective anther dehiscence, especially under heat stress. Phytohormone measurement revealed a significantly accumulation of indole-3-acetic acid (IAA) in the anthers of OsMATE16-KO mutants compared with WT. Moreover, the 9311 cultivar (OsMATE16Hap3) exhibits greater thermotolerance than the SSSL-OsMATE16Nip (OsMATE16Hap1), highlighting the potential of OsMATE16Hap3 as a valuable allele for breeding heat-tolerant rice. OsMATE16 regulates anther dehiscence by modulating auxin accumulation, thereby contributing to thermotolerance and stable seed-setting.