Zhang Yu, Zhang Yan-Jie, Yang Bao-Jun, Yu Xian-Xian, Wang Dun, Zu Song-Hao, Xue Hong-Wei, Lin Wen-Hui
State Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Sci Rep. 2016 Aug 8;6:31134. doi: 10.1038/srep31134.
Brassinosteroids (BRs) play key roles in plant growth and development, and regulate various agricultural traits. Enhanced BR signaling leads to increased seed number and yield in Arabidopsis bzr1-1D (AtBZR1(P234L), gain-of-function mutant of the important transcription factor in BR signaling/effects). BR signal transduction pathway is well elucidated in Arabidopsis but less known in other species. Soybean is an important dicot crop producing edible oil and protein. Phylogenetic analysis reveals AtBZR1-like genes are highly conserved in angiosperm and there are 4 orthologues in soybean (GmBZL1-4). We here report the functional characterization of GmBZL2 (relatively highly expresses in flowers). The P234 site in AtBZR1 is conserved in GmBZL2 (P216) and mutation of GmBZL2(P216L) leads to GmBZL2 accumulation. GmBZL2(P216L) (GmBZL2*) in Arabidopsis results in enhanced BR signaling; including increased seed number per silique. GmBZL2* partially rescued the defects of bri1-5, further demonstrating the conserved function of GmBZL2 with AtBZR1. BR treatment promotes the accumulation, nuclear localization and dephosphorylation/phosphorylation ratio of GmBZL2, revealing that GmBZL2 activity is regulated conservatively by BR signaling. Our studies not only indicate the conserved regulatory mechanism of GmBZL2 and BR signaling pathway in soybean, but also suggest the potential application of GmBZL2 in soybean seed yield.
油菜素类固醇（BRs）在植物生长发育中起关键作用，并调控多种农艺性状。增强BR信号传导会导致拟南芥bzr1-1D（AtBZR1(P234L)，BR信号传导/效应中重要转录因子的功能获得型突变体）的种子数量和产量增加。BR信号转导途径在拟南芥中已得到充分阐明，但在其他物种中了解较少。大豆是一种重要的双子叶作物，可生产食用油和蛋白质。系统发育分析表明，AtBZR1-like基因在被子植物中高度保守，大豆中有4个直系同源基因（GmBZL1-4）。我们在此报告了GmBZL2（在花中相对高表达）的功能特性。AtBZR1中的P234位点在GmBZL2（P216）中保守，GmBZL2(P216L)突变导致GmBZL2积累。拟南芥中的GmBZL2(P216L)（GmBZL2*）导致BR信号增强；包括每角果种子数量增加。GmBZL2*部分挽救了bri1-5的缺陷，进一步证明了GmBZL2与AtBZR1功能保守。BR处理促进了GmBZL2的积累、核定位以及去磷酸化/磷酸化比率，表明GmBZL2的活性受BR信号保守调控。我们的研究不仅表明了GmBZL2与大豆中BR信号通路的保守调控机制，还暗示了GmBZL2在大豆种子产量方面的潜在应用。
