Transcriptome analysis reveals insight into molecular hydrogen-induced cadmium tolerance in alfalfa: the prominent role of sulfur and (homo)glutathione metabolism
Transcriptome analysis reveals insight into molecular hydrogen-induced cadmium tolerance in alfalfa: the prominent role of sulfur and (homo)glutathione metabolism
复制标题
转录组分析揭示了苜蓿分子氢诱导的镉耐受性：硫和（同）谷胱甘肽代谢的突出作用
DOI：
10.1186/s12870-020-2272-2
复制
发表时间：
2020-02-04
影响因子：
5.3
通讯作者：
Shen, Wenbiao
中科院分区：
文献类型：
--
作者：
Cui, Weiti;Yao, Ping;Shen, Wenbiao
背景
氢气（H2）被认为在植物中通过调节信号转导和基因表达来应对逆境。虽然H2在植物对镉（Cd）的耐受性中的有益作用已被研究过，但其机制尚未阐明。本研究首次对镉和富氢水处理下苜蓿幼苗根系的转录组进行了分析。然后，从药理学和遗传学的角度对硫代谢途径进行了深入研究。
结果
利用RNA-Seq技术对镉和/或高辐射水处理下苜蓿幼苗根系中的1968个差异表达基因进行了鉴定。DEG被分为许多簇，包括谷胱甘肽（GSH）代谢，氧化应激和ATP结合盒（ABC）转运蛋白。RT-qPCR验证结果表明，镉胁迫下HRW处理提高了硫代谢相关基因的表达水平，尤其是（同型）谷胱甘肽代谢相关基因的表达。用谷胱甘肽合成抑制剂和拟南芥cad 2 -1突变体植物进行的其他实验表明谷胱甘肽在HRW诱导的镉耐受性中的突出作用。这些结果与HRW对（同型）谷胱甘肽和（同型）植物螯合素含量的影响以及缓解Cd胁迫下的氧化胁迫是一致的。此外，HRW诱导的缓解镉毒性也可能是由于减少有效镉在幼苗根系，通过ABC转运蛋白介导的分泌。
结论
综上所述，我们的研究结果表明，H2通过激活抗氧化和Cd螯合作用，调节硫和谷胱甘肽代谢相关基因的表达，增强谷胱甘肽代谢，从而导致Cd耐受。这些结果可能有助于阐明H2诱导苜蓿耐镉性的机制。
Background
Hydrogen gas (H2) is hypothesised to play a role in plants that are coping with stresses by regulating signal transduction and gene expression. Although the beneficial role of H2 in plant tolerance to cadmium (Cd) has been investigated previously, the corresponding mechanism has not been elucidated. In this report, the transcriptomes of alfalfa seedling roots under Cd and/or hydrogen-rich water (HRW) treatment were first analysed. Then, the sulfur metabolism pathways were focused on and further investigated by pharmacological and genetic approaches.
Results
A total of 1968 differentially expressed genes (DEGs) in alfalfa seedling roots under Cd and/or HRW treatment were identified by RNA-Seq. The DEGs were classified into many clusters, including glutathione (GSH) metabolism, oxidative stress, and ATP-binding cassette (ABC) transporters. The results validated by RT-qPCR showed that the levels of relevant genes involved in sulfur metabolism were enhanced by HRW under Cd treatment, especially the genes involved in (homo)glutathione metabolism. Additional experiments carried out with a glutathione synthesis inhibitor and Arabidopsis thaliana cad2–1 mutant plants suggested the prominent role of glutathione in HRW-induced Cd tolerance. These results were in accordance with the effects of HRW on the contents of (homo)glutathione and (homo)phytochelatins and in alleviating oxidative stress under Cd stress. In addition, the HRW-induced alleviation of Cd toxicity might also be caused by a decrease in available Cd in seedling roots, achieved through ABC transporter-mediated secretion.
Conclusions
Taken together, the results of our study indicate that H2 regulated the expression of genes relevant to sulfur and glutathione metabolism and enhanced glutathione metabolism which resulted in Cd tolerance by activating antioxidation and Cd chelation. These results may help to elucidate the mechanism governing H2-induced Cd tolerance in alfalfa.