Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China.
J Exp Bot. 2018 Jul 18;69(16):3933-3947. doi: 10.1093/jxb/ery220.
The phytohormones brassinosteroid (BR), auxin, and gibberellin (GA) regulate photomorphogenesis-related hypocotyl elongation in Arabidopsis via the co-operative interaction of BZR-ARF-PIF/DELLA (BAP/D) transcription factors/regulators. In addition, ethylene activates the PIF3 or ERF1 pathway through EIN3/EIL1 to balance hypocotyl elongation in Arabidopsis seedlings. However, the mechanism by which ethylene is co-ordinated with other phytohormones to produce light-regulated hypocotyl growth remains elusive. In this study, we found that hypocotyl cell elongation is regulated by a network involving ethylene, auxin, and BR signalling, which is mediated by interactions among ERF72, ARF6, and BZR1. ERF72 interacted directly with ARF6 and BZR1 in vitro and in vivo, and it antagonised regulation by ARF6 and BZR1 of the transcription of BEE3 and XTH7. In addition, light modulated the subcellular localisation of ERF72 and transcription of ERF72 through the EIN2-EIN3/EIL1 pathway, facilitating the function of ERF72 in photomorphogenesis. The expression of BEE3 and XTH7 was also regulated by the EIN2-EIN3/EIL1 pathway. Our findings indicate that a revised BZR-ARF-PIF/DELLA-ERF (BAP/DE) module integrates light and hormone signals to regulate hypocotyl elongation in Arabidopsis.
植物激素油菜素内酯（BR）、生长素和赤霉素（GA）通过 BZR-ARF-PIF/DELLA（BAP/D）转录因子/调节剂的协同相互作用调节拟南芥光形态发生相关的下胚轴伸长。此外，乙烯通过 EIN3/EIL1 激活 PIF3 或 ERF1 途径，以平衡拟南芥幼苗中下胚轴的伸长。然而，乙烯与其他植物激素协调产生光调控下胚轴生长的机制仍然难以捉摸。在这项研究中，我们发现乙烯、生长素和 BR 信号通路参与调控下胚轴细胞伸长，这是由 ERF72、ARF6 和 BZR1 之间的相互作用介导的。ERF72 在体外和体内直接与 ARF6 和 BZR1 相互作用，并拮抗 ARF6 和 BZR1 对 BEE3 和 XTH7 转录的调节。此外，光通过 EIN2-EIN3/EIL1 途径调节 ERF72 的亚细胞定位和转录，促进 ERF72 在光形态发生中的功能。BEE3 和 XTH7 的表达也受 EIN2-EIN3/EIL1 途径的调节。我们的研究结果表明，经过修订的 BZR-ARF-PIF/DELLA-ERF（BAP/DE）模块整合了光和激素信号，以调节拟南芥下胚轴的伸长。
