An emphasis of hydrogen sulfide-cysteine cycle on enhancing the tolerance to chromium stress in Arabidopsis

作者：Fang, Huihui; Liu, Zhiqiang; Jin, Zhuping; Zhang, Liping; Liu, Danmei; Pei, Yanxi^*

来源：Environmental Pollution, 2016, 213: 870-877.

DOI：10.1016/j.envpol.2016.03.035

• Hydrogen sulfide
• Signaling pathway
• Cysteine
• Sulfur metabolism
• Chromium stress

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.

• 出版日期2016-6
• 单位山西大学