The alterations of endogenous polyamines and phytohormones induced by exogenous application of spermidine regulate antioxidant metabolism, metallothionein and relevant genes conferring drought tolerance in white clover
The alterations of endogenous polyamines and phytohormones induced by exogenous application of spermidine regulate antioxidant metabolism, metallothionein and relevant genes conferring drought tolerance in white clover
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外源亚精胺诱导内源多胺和植物激素的改变调节白三叶草抗氧化代谢、金属硫蛋白和赋予耐旱性的相关基因
DOI：
10.1016/j.envexpbot.2015.12.004
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发表时间：
2016-04-01
影响因子：
5.7
通讯作者：
Yan, Yanhong
中科院分区：
文献类型：
--
作者：
Li, Zhou;Zhang, Yan;Yan, Yanhong
多胺与植物激素之间的交互作用可能参与植物耐旱性的调节。研究了外源亚精胺（Spd）及其抑制剂二甲基硫脲（DCHA）对白色三叶草（Trifolium repens）干旱响应的影响。代谢，蛋白质和基因转录水平进行了评估，在叶片相对含水量为87%的非胁迫植物和干旱胁迫植物的50%。外源Spd（0.05 mM）的应用显着增加内源PAs含量，而DCHA一般降低PAs含量。在非胁迫条件下，施亚精胺可提高赤霉素（GA）和吲哚乙酸（IAA）含量;在水分亏缺条件下，GA和细胞分裂素（CTK）含量增加，IAA含量降低。内源多胺的增加对脱落酸（ABA）的积累没有显着的影响下，任何水分处理。Spd处理通过维持更高的抗氧化酶活性和转录水平，特别是抗坏血酸（阿萨），增强抗氧化防御。其他代谢产物如总酚、类黄酮、脯氨酸、金属硫蛋白（MT）和半胱氨酸（Cyt）也随着亚精胺处理而升高。相反，Spd生物合成的抑制削弱了抗氧化防御，降低了脯氨酸代谢，抑制MT基因的表达，导致干旱胁迫伤害加剧。这些结果表明，多胺和植物激素的变化在白色三叶草耐旱性的提高中起着重要作用，其机制可能是减轻氧化胁迫，抑制叶片衰老，维持干旱胁迫下的生长。(C)2015 Elsevier B.V.版权所有。
Cross-talk between polyamines (PAs) and phytohormones may be involved in the regulation of drought tolerance in plants. The objective of this study was to determine the effects of exogenous spermidine (Spd) and a Spd inhibitor, dimethylthiourea (DCHA), on drought responses of white clover (Trifolium repens). Metabolic, protein, and gene transcript levels were evaluated at leaf relative water content levels of 87% for non-stressed plants and 50% for drought-stressed plants. The exogenous application of Spd (0.05 mM) significantly increased endogenous PAs content whereas DCHA generally reduced PAs content. Phytohormone responses to Spd application included an elevated gibberellic acid (GA) and indole-3-acetic acid (IAA) content under non-stressed condition, and an increased GA and cytokinin (CTK) content as well as decreased IAA content under water deficit condition. The increase in endogenous PAs had no significant effect on abscisic acid (ABA) accumulation under either water treatment. Spd treatment resulted in enhanced antioxidant defense via maintenance of greater antioxidant enzyme activities and transcript levels, especially ascorbic acid (AsA). Other metabolites such as total phenols, flavonoids, proline, metallothionein (MT), and cysteine (Cyt) were also elevated with Spd treatment. On the contrary, inhibition of Spd biosynthesis weakened antioxidant defense, decreased proline metabolism, and inhibited MT genes expression leading to aggravation of drought-induced stress damages. These results suggest that changes of PAs and phytohormones play critical roles in the improvement of drought tolerance in white clover, which are attributed to the alleviation of oxidative stress, inhibition of leaf senescence, and maintenance of growth under drought stress. (C) 2015 Elsevier B.V. All rights reserved.