Zhang Pan, Qian Dong, Luo Changxin, Niu Yingzhi, Li Tian, Li Chengying, Xiang Yun, Wang Xinyu, Niu Yue
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
Front Cell Dev Biol. 2021 Jan 28;9:635533. doi: 10.3389/fcell.2021.635533. eCollection 2021.
Low temperature is a major adverse environment that affects normal plant growth. Previous reports showed that the actin cytoskeleton plays an important role in the plant response to low-temperature stress, but the regulatory mechanism of the actin cytoskeleton in this process is not clear. C-repeat binding factors (CBFs) are the key molecular switches for plants to adapt to cold stress. However, whether CBFs are involved in the regulation of the actin cytoskeleton has not been reported. We found that (), an ADF that evolved F-actin bundling function, was up-regulated at low temperatures. We also demonstrated that CBFs bound to the promoter directly and . The cold-induced expression of was significantly inhibited in the triple mutant. The freezing resistance of the knockout mutant was weaker than that of wild type (WT) with or without cold acclimation. After low-temperature treatment, the actin cytoskeleton of WT was relatively stable, but the actin cytoskeletons of , and were disturbed to varying degrees. Compared to WT, the endocytosis rate of the amphiphilic styryl dye FM4-64 in , and at low temperature was significantly reduced. In conclusion, CBFs directly combine with the CRT/DRE DNA regulatory element of the promoter after low-temperature stress to transcriptionally activate the expression of ; ADF5 further regulates the actin cytoskeleton dynamics to participate in the regulation of plant adaptation to a low-temperature environment.
低温是影响植物正常生长的主要逆境环境。先前的报道表明，肌动蛋白细胞骨架在植物对低温胁迫的响应中起重要作用，但在此过程中肌动蛋白细胞骨架的调控机制尚不清楚。C-重复结合因子（CBFs）是植物适应冷胁迫的关键分子开关。然而，CBFs是否参与肌动蛋白细胞骨架的调控尚未见报道。我们发现，一种具有F-肌动蛋白成束功能的ADF（）在低温下上调。我们还证明，CBFs直接与的启动子结合并且。在三重突变体中，的冷诱导表达显著受到抑制。无论是否经过冷驯化，敲除突变体的抗冻性均弱于野生型（WT）。低温处理后，WT的肌动蛋白细胞骨架相对稳定，但、和的肌动蛋白细胞骨架受到不同程度的干扰。与WT相比，、和在低温下两亲性苯乙烯基染料FM4-64的内吞率显著降低。综上所述，低温胁迫后CBFs直接与的启动子的CRT/DRE DNA调控元件结合，转录激活的表达；ADF5进一步调节肌动蛋白细胞骨架动力学，参与植物对低温环境适应的调控。
