Chemical regulation of abscisic acid catabolism in plants by cytochrome P450 inhibitors
Chemical regulation of abscisic acid catabolism in plants by cytochrome P450 inhibitors
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DOI：
10.1016/j.bmc.2005.04.036
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发表时间：
2005-07-15
影响因子：
3.5
通讯作者：
Asami, T
中科院分区：
文献类型：
--
作者：
Kitahata, N;Saito, S;Asami, T
植物激素脱落酸(ABA)是提高植物抗旱性的重要因素。因此，调节植物中ABA水平的小分子对于研究ABA的功能和开发新的植物生长调节剂都是有用的。脱落酸(ABA)在植物体内的分解代谢主要受细胞色素P450(P450)的ABA 8‘-羟基酶的调节。我们测试了已知的含有三唑基团的P450抑制剂，发现烯效唑-P抑制了培养的烟草光明黄-2细胞中ABA的分解代谢。在烯效唑的构效关系研究中，我们发现了一种比烯效唑-P更有效的ABA分解代谢抑制剂(烯唑醇)。在体外实验中，杀菌剂烯效唑对重组拟南芥ABA 8‘-羟基酶CYP707A3具有竞争性抑制作用。在复水过程中，烯效唑处理的植株比未处理的植株保留了更高的ABA含量和ABA反应基因的转录水平，并且比未处理的植株更耐旱。这些结果有力地表明，以ABA 8‘-羟基酶为靶标的ABA分解代谢抑制剂可以调节植物的ABA含量，从而增强植物的抗旱性。烯唑醇的光学拆分表明，S异构体是一种较弱的杀菌异构体，其作为脱落酸分解代谢抑制剂的活性高于R型异构体。(C)2005爱思唯尔有限公司。保留所有权利。
Plant hormone abscisic acid (ABA) is an important factor for conferring drought stress resistance on plants. Therefore, small molecules that regulate ABA levels in plants can be useful both for investigating functions of ABA and for developing new plant growth regulators. Abscisic acid (ABA) catabolism in plants is primarily regulated by ABA 8'-hydroxylase, which is a cytochrome P450 (P450). We tested known P450 inhibitors containing a triazole group and found that uniconazole-P inhibited ABA catabolism in cultured tobacco Bright Yellow-2 cells. In a structure-activity study of uniconazole, we found a more effective ABA catabolic inhibitor (diniconazole) than uniconazole-P. Diniconazole, a fungicide, acted as a potent competitive inhibitor of recombinant Arabidopsis ABA 8'-hydroxylase, CYP707A3, in an in vitro assay. Diniconazole-treated plants retained a higher ABA content and higher transcription levels of ABA response genes during rehydration than did untreated plants and were more drought stress tolerant than untreated plants. These results strongly suggest that ABA catabolic inhibitors that target ABA 8'-hydroxylase can regulate the ABA content of plants and conferred drought stress resistance on plants. The optical resolution of diniconazole revealed that the S-form isomer, which is a weak fungicidal isomer, was more active as an ABA catabolic inhibitor than was the R-form isomer. (c) 2005 Elsevier Ltd. All rights reserved.