An emphasis of hydrogen sulfide-cysteine cycle on enhancing the tolerance to chromium stress in Arabidopsis
An emphasis of hydrogen sulfide-cysteine cycle on enhancing the tolerance to chromium stress in Arabidopsis
复制标题
硫化氢-半胱氨酸循环对增强拟南芥铬胁迫耐受性的强调
DOI：
10.1016/j.envpol.2016.03.035
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发表时间：
2016-06-01
影响因子：
8.9
通讯作者：
Pei, Yanxi
中科院分区：
文献类型：
--
作者：
Fang, Huihui;Liu, Zhiqiang;Pei, Yanxi
种植在受重金属污染的农田土壤中的蔬菜和粮食的健康问题日益受到人们的关注，因此寻找降低重金属在植物中积累的方法具有重要意义。由于硫被认为是植物逆境防御的必需常量营养素，因此硫同化在植物响应HMs胁迫中的重要作用一直受到关注。然而，唯一的含硫气体递质硫化氢（H2S）及其主要内源底物半胱氨酸（Cys）在植物防御中的潜在机制知之甚少。采用生理生化方法和qRT-PCR技术研究了植物对铬（Cr 6+）胁迫的H2S-Cys循环响应模式。结果表明，Cr ~（6+）胁迫抑制拟南芥根的伸长，提高H_2S和Cys含量，且H_2S的产生早于Cys。此外，H2S胁迫比Cr 6+胁迫更快地增加了Cys的积累。qRT-PCR结果显示，H2S可上调Cys生成相关基因OASTLa、SAT 1和SATS的表达水平，且SAT 1和SATS的表达上调持续时间较长。数据表明，H2S可能调节Cys代谢相关基因的表达，从而参与Cr 6+介导的Cys积累。H2S和Cys缓解了Cr 6+对拟南芥根伸长的抑制。H2S和Cys均通过上调PCS 1和PCS 2的表达水平来增强谷胱甘肽的生成并激活植物螯合素（PCs）的合成以对抗Cr 6+胁迫。H2S除了调控PCs合成酶编码基因的表达外，还可能通过显著增加MT 2A基因的表达来促进金属硫蛋白的积累。总体而言，H2S和H2S诱导的Cys积累（H2S-Cys系统）在拟南芥中赋予Cr 6+耐受性是至关重要的。本文首次指出气体递质H2S在拟南芥Cr 6+胁迫防御中诱导Cys积累，为更广泛地研究H2S信号通路提供了证据。(C)2016爱思唯尔有限公司版权所有。
Increasing attention has been focused on the health of vegetables and grains grown in the contaminated agricultural soil, it is thus meaningful to find ways to reduce the heavy metals (HMs) accumulation in plants. As sulfur is considered to be an essential macronutrient for plant stress defenses, the important role of sulfur assimilation in plants responding to HMs stress has been followed. However, the potential mechanism of the only sulfur-containing gasotransmitter hydrogen sulfide (H2S) and its main endogenously generated substrate, cysteine (Cys), in plant defense is poorly understood. The physiological and biochemical methods together with qRT-PCR were used to explore the response pattern of H2S-Cys cycle in plants resisting to chromium (Cr6+) stress. Our results suggested that Cr6+ stress inhibited Arabidopsis root elongation, increased the H2S and Cys contents time-dependently, and H2S production was activated earlier than Cys. Furthermore, H2S increased Cys accumulation more quickly than Cr6+ stress. The qRTPCR results revealed that H2S up-regulated the Cys generation-related genes OASTLa, SAT1 and SATS expression levels, and that SAT1 and SATS expression was elevated for a longer duration. Data suggested that H2S might regulate Cys metabolism-related genes expression to participate in Cr6+-mediated Cys accumulation. H2S and Cys relieved the root elongation inhibition caused by Cr6+ in Arabidopsis. Both H2S and Cys enhanced glutathione generation and activated phytochelatins (PCs) synthesis by up-regulating PCS1 and PCS2 expression levels to fight against Cr6+ stress. Besides regulating the expression of PCs synthase encoding genes, H2S might promote metallothioneins accumulation by significantly increasing the MT2A gene expression. Overall, H2S and H2S-induced Cys accumulation (H2S-Cys system) was critical in imparting Cr6+ tolerance in Arabidopsis. This paper is the first to indicate that gasotransmitter H2S induced Cys accumulation in Arabidopsis Cr6+-stress defense and provides evidence for more extensive studies of the H2S signaling pathway. (C) 2016 Elsevier Ltd. All rights reserved.