Two B-Box Domain Proteins, BBX18 and BBX23, Interact with ELF3 and Regulate Thermomorphogenesis in Arabidopsis
Two B-Box Domain Proteins, BBX18 and BBX23, Interact with ELF3 and Regulate Thermomorphogenesis in Arabidopsis
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DOI：
10.1016/j.celrep.2018.10.060
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发表时间：
2018-11-13
期刊：
影响因子：
8.8
通讯作者：
Liu, Jian-Xiang
中科院分区：
文献类型：
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作者：
Ding, Lan;Wang, Shuo;Liu, Jian-Xiang
植物通过各种内源信号和环境胁迫来协调其生长和发育进程。光敏色素相互作用因子4（PIF4）在拟南芥的温度响应基因表达和下胚轴生长中起关键的正向作用，而早花3（ELF3）在高温下负向调控PIF4的活性。然而，ELF3的活性在温暖温度下是如何被调控的尚不清楚。在此，我们报道了B - box 18（BBX18）和BBX23作为拟南芥中重要的热形态建成调控因子的鉴定结果。BBX18和BBX23突变导致温度响应性下胚轴伸长减少。相反，BBX18的过表达促进高温下的下胚轴生长，这依赖于PIF4或组成型光形态建成1（COP1）。BBX18和BBX23与ELF3或COP1相互作用。敲除BBX18和BBX23在正常和温暖温度条件下都会增加ELF3的丰度。多个温度响应基因在PIF4突变体和BBX18/BBX23双突变体中的表达均受损。因此，我们的研究结果揭示了B - box蛋白在热形态建成过程中的重要作用，并为我们理解温暖温度信号如何调控ELF3活性以及PIF4依赖基因提供了见解。
Plants coordinate their growth and developmental programs with various endogenous signals and environmental challenges. Phytochrome interacting factor 4 (PIF4) plays a critical positive role in thermoresponsive gene expression and hypocotyl growth in Arabidopsis, whereas early flowering 3 (ELF3) negatively regulates the activity of PIF4 at elevated temperatures. However, it is unknown how ELF3 activity is regulated at warm temperatures. Here, we report the identification of B-box 18 (BBX18) and BBX23 as important thermomorphogenesis regulators in Arabidopsis. BBX18 and BBX23 mutations result in reduced thermoresponsive hypocotyl elongation. In contrast, BBX18 overexpression promotes hypocotyl growth at elevated temperatures, which depends on either PIF4 or constitutive photomorphogenic 1 (COP1). BBX18 and BBX23 interact with ELF3 or COP1. Knocking out BBX18 and BBX23 increases ELF3 abundance under normal and warm temperature conditions. The expression of multiple thermoresponsive genes is impaired in both a PIF4 mutant and a BBX18/BBX23 double mutant. Thus, our findings reveal an important role of B-box proteins during thermomorphogenesis and provide insights into our understanding of how warm temperature signals regulate ELF3 activity and PIF4-dependent genes.