背景回顾：Plants sense and respond to fluctuating temperature and light conditions during the circadian cycle; however, the molecular mechanism underlying plant adaptability during daytime warm conditions remains poorly understood. 

主要发现：In this study, we reveal that ectopic regulation of a HEAT RESPONSIVE PROTEIN (GhHRP) controls the adaptation and survival of cotton (Gossypium hirsutum) plants in response to warm conditions via modulating phytohormone signaling. 

结果1-暖温诱导表达：Increased ambient temperature promptly enhanced binding of the phytochrome interacting factor 4 (GhPIF4)/ethylene-insensitive 3 (GhEIN3) complex to the GhHRP promoter to increase its mRNA level. 

结果2-GhHRP异位表达表型：Ectopic expression of GhHRP promoted temperature-dependent accumulation of GhPIF4 transcripts and hypocotyl elongation by triggering thermoresponsive growth-related genes. 

结果3-影响YUC和ACS基因的表达：Notably, upregulation of the GhHRP/GhPIF4 complex improved plant growth via modulating the abundance of Arabidopsis thaliana auxin biosynthetic gene YUCCA8 (AtYUC8)/1-aminocyclopropane-1-carboxylate synthase 8 (AtACS8) for fine-tuning the auxin/ethylene interplay, ultimately resulting in decreased ethylene biosynthesis. GhHRP thus protects chloroplasts from photo-oxidative bursts via repressing AtACS8 and AtACS7 and promoting AtYUC8 and the heat shock transcription factors (HSFA2), heat shock proteins (HSP70 and HSP20). 

结果4-HRP突变表型：Strikingly, the Δhrp disruption mutant exhibited compromised production of HSP/YUC8 that resulted in an opposite phenotype with loss of the ability to respond to warm conditions. 

结论：Our results show that GhHRP is a heat-responsive signaling component that assists plants in confronting the dark phase and modulates auxin signaling to rescue growth under temperature fluctuations.

植物在其生物周期中，能够感知并响应所处环境的温度和光照条件；但是，植物在白天温暖条件下的适应性分子调控机制仍不清楚。本文中，作者发现GhHRP基因的异位表达能够通过调控植物激素信号转导来响应温暖环境条件，从而控制棉花的适应性和存活。环境温度的增加会增强GhPIF4/GhEIN3复合体结合到GhHRP基因启动子上的能力，从而上调GhHRP基因的表达。异位表达GhHRP基因会促进温度依赖性的GhPIF4转录本积累，并通过诱导温敏相关生长基因的表达促进下胚轴的伸长。尤其是，GhHRP/GhPIF复合物的上调会通过调控拟南芥生长素合成基因AtYUC8和乙烯生物合成基因AtACS8的表达，精确调控生长素与乙烯之间的互作，导致乙烯生物合成的降低，最终增强植物的生长。因此，GhHRP基因通过抑制乙烯生物合成相关基因AtACS8和AtACS7的表达，促进生长素生物合成基因AtYUC8和热激转录因子HSFA2以及热激蛋白HSP70和HSP20的表达，保护叶绿体免受光氧化爆发的损伤。有趣的是，Δhrp扰乱突变体存在HSP/YUC8表达的缺陷，导致了相反的表型，即丢失响应温暖环境的能力。本文的研究结果表明GhHRP是一个热响应信号转导组分，帮助植物面对日周期中的黑暗阶段，并通过调控生长素信号转导帮助植物在温度波动下恢复生长。

** 张天真 **