State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310027, China.
Department of Biology, University of York, Heslington, York, YO105DD, UK.
J Integr Plant Biol. 2021 Jun;63(6):1097-1103. doi: 10.1111/jipb.13107. Epub 2021 Jun 8.
Plants are capable of coordination of their growth and development with ambient temperatures. EARLY FLOWERING3 (ELF3), an essential component of the plant circadian clock, is also involved in ambient temperature sensing, as well as in inhibiting the expression and protein activity of the thermoresponsive regulator phytochrome interacting factor 4 (PIF4). The ELF3 activity is subjected to attenuation in response to warm temperature; however, how the protein level of ELF3 is regulated at warm temperature remains less understood. Here, we report that the E3 ligase XB3 ORTHOLOG 5 IN ARABIDOPSIS THALIANA, XBAT35, mediates ELF3 degradation. XBAT35 interacts with ELF3 and ubiquitinates ELF3. Loss-of-function mutation of XBAT35 increases the protein level of ELF3 and confers a short-hypocotyl phenotype under warm temperature conditions. Thus, our findings establish that XBAT35 mediates ELF3 degradation to lift the inhibition of ELF3 on PIF4 for promoting thermoresponsive hypocotyl growth in plants.
植物能够协调其生长和发育与环境温度。EARLY FLOWERING3（ELF3），植物生物钟的一个重要组成部分，也参与环境温度感应，以及抑制热响应调节因子光敏色素相互作用因子 4（PIF4）的表达和蛋白活性。ELF3 的活性在响应温暖温度时受到衰减；然而，ELF3 的蛋白水平如何在温暖温度下受到调节，目前还不太清楚。在这里，我们报告说，E3 连接酶 XB3 ORTHOLOG 5 IN ARABIDOPSIS THALIANA，XBAT35，介导 ELF3 的降解。XBAT35 与 ELF3 相互作用并泛素化 ELF3。XBAT35 的功能丧失突变增加了 ELF3 的蛋白水平，并在温暖条件下赋予短下胚轴表型。因此，我们的研究结果表明，XBAT35 介导 ELF3 的降解，以解除 ELF3 对 PIF4 的抑制，从而促进植物的热响应性下胚轴生长。
