Abnormal high temperature (HT) caused by global warming threatens plant survival and food security, but the effects of HT on plant organ identity are elusive. Here, we show that Class II TEOSINTE BRANCHED 1/CYCLOIDEA/ PCF (TCP) transcription factors redundantly protect ovule identity under HT. The duodecuple tcp2/3/4/5/10/13/17/24/1/12/18/16 (tcpDUO) mutant displays HT-induced ovule conversion into carpelloid structures. Expression of TCP4 in tcpDUO complements the ovule identity conversion. TCP4 interacts with AGAMOUS (AG), SEPALLATA3 (SEP3), and the homeodomain transcription factor BELL1 (BEL1) to strengthen the association of BEL1 with AG-SEP3. The tcpDUO mutant synergistically interacts with bel1 and the ovule identity gene seedstick (STK) mutant stk in tcpDUO bel1 and tcpDUO stk. Our findings reveal the critical roles of Class II TCPs in maintaining ovule identity under HT and shed light on the molecular mechanisms by which ovule identity is determined by the integration of internal factors and environmental temperature.

全球变暖引起的异常高温（HT）威胁着植物的生存和粮食安全，但高温对植物器官特性的影响却难以捉摸。在这里，我们表明 II 类 TEOSINTE BRANCHED 1/CYCLOIDEA/ PCF (TCP) 转录因子在 HT 下冗余地保护胚珠身份。十二倍体tcp2/3/4/5/10/13/17/24/1/12/18/16 (tcpDUO)突变体表现出 HT 诱导的胚珠转化为心皮结构。TCP4在tcpDUO中的表达补充了胚珠身份转换。TCP4 与 AGAMOUS (AG)、SEPALLATA3 (SEP3) 和同源域转录因子 BELL1 (BEL1) 相互作用，以加强 BEL1 与 AG-SEP3 的关联。tcpDUO突变体与 tcpDUO bel1和tcpDUO stk中的bel1和胚珠识别基因seedstick ( STK ) 突变体 stk协同相互作用。我们的研究结果揭示了 II 类TCP在高温下维持胚珠身份的关键作用，并揭示了胚珠身份由内部因素和环境温度综合决定的分子机制。