Department of Horticulture, Zhejiang University, Hangzhou 310058, China.
Boyce Thompson Institute, Cornell University, Ithaca, NY 14853, USA.
Plant Cell. 2021 Aug 13;33(7):2320-2339. doi: 10.1093/plcell/koab120.
Extreme temperature conditions seriously impair male reproductive development in plants; however, the molecular mechanisms underlying the response of anthers to extreme temperatures remain poorly described. The transcription factor phytochrome-interacting factor4 (PIF4) acts as a hub that integrates multiple signaling pathways to regulate thermosensory growth and architectural adaptation in plants. Here, we report that SlPIF4 in tomato (Solanum lycopersicum) plays a pivotal role in regulating cold tolerance in anthers. CRISPR (clustered regularly interspaced short palindromic repeats)-associated nuclease Cas9-generated SlPIF4 knockout mutants showed enhanced cold tolerance in pollen due to reduced temperature sensitivity of the tapetum, while overexpressing SlPIF4 conferred pollen abortion by delaying tapetal programmed cell death (PCD). SlPIF4 directly interacts with SlDYT1, a direct upstream regulator of SlTDF1, both of which (SlDYT1 and SlTDF1) play important roles in regulating tapetum development and tapetal PCD. Moderately low temperature (MLT) promotes the transcriptional activation of SlTDF1 by the SlPIF4-SlDYT1 complex, resulting in pollen abortion, while knocking out SlPIF4 blocked the MLT-induced activation of SlTDF1. Furthermore, SlPIF4 directly binds to the canonical E-box sequence in the SlDYT1 promoter. Collectively, these findings suggest that SlPIF4 negatively regulates cold tolerance in anthers by directly interacting with the tapetal regulatory module in a temperature-dependent manner. Our results shed light on the molecular mechanisms underlying the adaptation of anthers to low temperatures.
极端温度条件严重损害植物雄性生殖发育；然而，花药对极端温度响应的分子机制仍描述甚少。光受体相互作用因子 4（PIF4）作为一个枢纽，整合多个信号通路，调节植物的热感觉生长和结构适应。在这里，我们报告番茄（Solanum lycopersicum）中的 SlPIF4 在调节花药耐冷性中起着关键作用。CRISPR（成簇规律间隔短回文重复）相关核酸酶 Cas9 产生的 SlPIF4 敲除突变体由于绒毡层的温度敏感性降低，花粉表现出增强的耐冷性，而过表达 SlPIF4 通过延迟绒毡层程序性细胞死亡（PCD）导致花粉败育。SlPIF4 与 SlDYT1 直接相互作用，SlDYT1 是 SlTDF1 的直接上游调节剂，两者（SlDYT1 和 SlTDF1）在调节绒毡层发育和绒毡层 PCD 中都起着重要作用。适度低温（MLT）促进 SlPIF4-SlDYT1 复合物对 SlTDF1 的转录激活，导致花粉败育，而敲除 SlPIF4 阻止了 MLT 诱导的 SlTDF1 激活。此外，SlPIF4 直接结合 SlDYT1 启动子中的典型 E 盒序列。总之，这些发现表明 SlPIF4 通过与绒毡层调节模块以温度依赖的方式直接相互作用，负调控花药的耐冷性。我们的研究结果揭示了花药适应低温的分子机制。
