National Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China.
Department of Plant and Microbial Biology, University of Minnesota at Twin Cities, Saint Paul, MN 55108, USA.
Plant Commun. 2021 Nov 12;3(2):100265. doi: 10.1016/j.xplc.2021.100265. eCollection 2022 Mar 14.
WRKY transcription factors are known mostly for their function in plant defense, abiotic stress responses, senescence, seed germination, and development of the pollen, embryo, and seed. Here, we report the regulatory functions of two WRKY proteins in photomorphogenesis and expression. PIF4 is a critical signaling hub in light, temperature, and hormonal signaling pathways. Either its expression or its accumulation peaks in the morning and afternoon. WRKY2 and WRKY10 form heterodimers and recognize their target site in the promoter near the MYB element that is bound by CCA1 and LHY under red and blue light. WRKY2 and WRKY10 interact directly with CCA1/LHY to enhance their targeting but interact indirectly with SHB1. The two WRKY proteins also interact with phyB, and their interaction enhances the targeting of CCA1 and LHY to the promoter. SHB1 associates with the and loci and enhances their expression in parallel with the expression peaks. This forward regulatory loop further sustains the accumulation of the two WRKY proteins and the targeting of CCA1/LHY to the locus. In summary, interactions of two WRKY proteins with CCA1/LHY and phyB maintain an optimal expression level of toward noon and afternoon, which is essential to sketch the circadian pattern of expression.
WRKY 转录因子主要因其在植物防御、非生物胁迫响应、衰老、种子萌发以及花粉、胚胎和种子发育中的功能而被人们所熟知。在这里，我们报告了两个 WRKY 蛋白在光形态建成和表达中的调节功能。PIF4 是光、温度和激素信号通路中的关键信号枢纽。无论是其表达还是积累，都在早上和下午达到峰值。WRKY2 和 WRKY10 形成异源二聚体，并识别其靶位点位于 MYB 元件附近的 启动子中，该靶位点在红光和蓝光下由 CCA1 和 LHY 结合。WRKY2 和 WRKY10 直接与 CCA1/LHY 相互作用以增强其靶向性，但间接与 SHB1 相互作用。这两个 WRKY 蛋白还与 phyB 相互作用，其相互作用增强了 CCA1 和 LHY 对 启动子的靶向性。SHB1 与 和 基因座结合，并与 基因座的表达平行增强其表达。这种正向调控环进一步维持了两种 WRKY 蛋白的积累以及 CCA1/LHY 对 基因座的靶向性。总之，两个 WRKY 蛋白与 CCA1/LHY 和 phyB 的相互作用维持了 基因在中午和下午的最佳表达水平，这对于描绘 基因表达的昼夜节律模式至关重要。
