Abscisic acid analogs as chemical probes for dissection of abscisic acid responses in Arabidopsis thaliana
Abscisic acid analogs as chemical probes for dissection of abscisic acid responses in Arabidopsis thaliana
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DOI：
10.1016/j.phytochem.2014.03.017
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发表时间：
2015-05-01
期刊：
影响因子：
3.8
通讯作者：
Loewen, Michele C.
中科院分区：
文献类型：
--
作者：
Benson, Chantel L.;Kepka, Michal;Loewen, Michele C.
脱落酸（阿坝）是一种植物激素，参与调节植物的生长发育过程和对环境胁迫的反应。在拟南芥中，阿坝通过称为阿坝受体调节组分（RCAR）/吡拉菌素抗性1（PYR 1）/吡拉菌素抗性样（PYL）受体的遗传冗余的阿坝受体家族起作用，该家族由13个同源物组成，与7个成员的磷酸酶组一起起作用。A.对于拟南芥RCAR及其结合配偶体的特定生理功能还知之甚少。为了开发对特定阿坝功能具有选择性的有效植物生长调节剂和用于阐明阿坝感知的工具，组装了一组在阿坝环周围位置上特异性改变的阿坝类似物。这些类似物已用于探测十三种RCAR和四种2C型蛋白磷酸酶（PP 2C 5），并且还针对模型植物拟南芥中的代表性生理测定进行了筛选。（S）-阿坝的1 '-O甲基醚被鉴定为选择性的，因为在生理相关水平，它调节气孔开度并提高耐旱性，但不抑制发芽或根生长。阿坝环的7 '-和8'-甲基被更大的基团取代的类似物通常保留了（S）-和（R）-阿坝的活性和立体选择性，而9 '-甲基的改变提供了替代阿坝抑制萌发但既不抑制根生长也不抑制气孔关闭的类似物。进一步的体外测试表明类似物与单个RCAR的结合存在差异，以及由与RCAR-类似物复合物结合的特异性PP 2C引起的酶活性差异。最终，这些研究结果突出了一个更广泛的化学遗传学方法的潜力，解剖复杂的网络介导ABA的感知，信号和功能在一个给定的物种和修改在未来的设计阿坝激动剂。皇冠版权所有（C）2014由爱思唯尔有限公司出版。保留所有权利。
Abscisic acid (ABA) is a phytohormone known to mediate numerous plant developmental processes and responses to environmental stress. In Arabidopsis thaliana, ABA acts, through a genetically redundant family of ABA receptors entitled Regulatory Component of ABA Receptor (RCAR)/Pyrabactin Resistant 1 (PYR1)/Pyrabactin Resistant-Like (PYL) receptors comprised of thirteen homologues acting in concert with a seven-member set of phosphatases. The individual contributions of A. thaliana RCARs and their binding partners with respect to specific physiological functions are as yet poorly understood. Towards developing efficacious plant growth regulators selective for specific ABA functions and tools for elucidating ABA perception, a panel of ABA analogs altered specifically on positions around the ABA ring was assembled. These analogs have been used to probe thirteen RCARs and four type 2C protein phosphatases (PP2C5) and were also screened against representative physiological assays in the model plant Arabidopsis. The 1'-O methyl ether of (S)-ABA was identified as selective in that, at physiologically relevant levels, it regulates stomatal aperture and improves drought tolerance, but does not inhibit germination or root growth. Analogs with the 7'- and 8'-methyl groups of the ABA ring replaced with bulkier groups generally retained the activity and stereoselectivity of (S)- and (R)-ABA, while alteration of the 9'-methyl group afforded an analog that substituted for ABA in inhibiting germination but neither root growth nor stomatal closure. Further in vitro testing indicated differences in binding of analogs to individual RCARs, as well as differences in the enzyme activity resulting from specific PP2Cs bound to RCAR-analog complexes. Ultimately, these findings highlight the potential of a broader chemical genetics approach for dissection of the complex network mediating ABA-perception, signaling and functionality within a given species and modifications in the future design of ABA agonists. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.