Mao Jie-Li, Miao Zi-Qing, Wang Zhen, Yu Lin-Hui, Cai Xiao-Teng, Xiang Cheng-Bin
School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province, China.
Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province, China.
PLoS Genet. 2016 Jan 8;12(1):e1005760. doi: 10.1371/journal.pgen.1005760. eCollection 2016 Jan.
The gaseous phytohormone ethylene participates in the regulation of root growth and development in Arabidopsis. It is known that root growth inhibition by ethylene involves auxin, which is partially mediated by the action of the WEAK ETHYLENE INSENSITIVE2/ANTHRANILATE SYNTHASE α1 (WEI2/ASA1), encoding a rate-limiting enzyme in tryptophan (Trp) biosynthesis, from which auxin is derived. However, the molecular mechanism by which ethylene decreases root growth via ASA1 is not understood. Here we report that the ethylene-responsive AP2 transcription factor, ETHYLENE RESPONSE FACTOR1 (ERF1), plays an important role in primary root elongation of Arabidopsis. Using loss- and gain-of-function transgenic lines as well as biochemical analysis, we demonstrate that ERF1 can directly up-regulate ASA1 by binding to its promoter, leading to auxin accumulation and ethylene-induced inhibition of root growth. This discloses one mechanism linking ethylene signaling and auxin biosynthesis in Arabidopsis roots.
气态植物激素乙烯参与拟南芥根系生长发育的调控。已知乙烯对根系生长的抑制作用涉及生长素，这部分是由编码色氨酸（Trp）生物合成限速酶的弱乙烯不敏感2/邻氨基苯甲酸合酶α1（WEI2/ASA1）的作用介导的，生长素即来源于色氨酸。然而，乙烯通过ASA1降低根系生长的分子机制尚不清楚。在此我们报道，乙烯响应型AP2转录因子乙烯响应因子1（ERF1）在拟南芥主根伸长中起重要作用。通过功能缺失和功能获得转基因系以及生化分析，我们证明ERF1可通过结合其启动子直接上调ASA1，导致生长素积累以及乙烯诱导的根系生长抑制。这揭示了拟南芥根系中乙烯信号传导与生长素生物合成之间的一种联系机制。
