Yang Yan-Zhuo, Tan Bao-Cai
Institute of Plant Molecular Biology and Agricultural Biotechnology, State Key Lab of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
PLoS One. 2014 Jan 27;9(1):e87283. doi: 10.1371/journal.pone.0087283. eCollection 2014.
The plant hormone abscisic acid (ABA) plays a crucial role in plant development and responses to abiotic stresses. Recent studies indicate that a positive feedback regulation by ABA exists in ABA biosynthesis in plants under dehydration stress. To understand the molecular basis of this regulation, we analyzed the cis-elements of the AtNCED3 promoter in Arabidopsis. AtNCED3 encodes the first committed and highly regulated dioxygenase in the ABA biosynthetic pathway. Through delineated and mutagenesis analyses in stable-transformed Arabidopsis, we revealed that a distal ABA responsive element (ABRE: GGCACGTG, -2372 to -2364 bp) is required for ABA-induced AtNCED3 expression. By analyzing the AtNCED3 expression in ABRE binding protein ABF3 over-expression transgenic plants and knock-out mutants, we provide evidence that the ABA feedback regulation of AtNCED3 expression is not mediated by ABF3.
植物激素脱落酸（ABA）在植物发育及对非生物胁迫的响应中起着关键作用。最近的研究表明，脱水胁迫下植物ABA生物合成中存在由ABA介导的正反馈调节。为了解这种调节的分子基础，我们分析了拟南芥AtNCED3启动子的顺式作用元件。AtNCED3编码ABA生物合成途径中首个关键且受高度调控的双加氧酶。通过对稳定转化的拟南芥进行精细定位和诱变分析，我们发现一个远端ABA响应元件（ABRE：GGCACGTG，-2372至-2364 bp）对于ABA诱导的AtNCED3表达是必需的。通过分析ABRE结合蛋白ABF3过表达转基因植物和敲除突变体中AtNCED3的表达，我们提供了证据表明AtNCED3表达的ABA反馈调节不是由ABF3介导的。
