| 外源亚精胺调控黑麦草根系响应镉胁迫及其转录组学分析 |
| 摘要点击 2524 全文点击 784 投稿时间：2022-10-08 修订日期：2022-12-25 |
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| 中文关键词 亚精胺(Spd) 黑麦草 镉(Cd) 调控机制 转录组学 |
| 英文关键词 spermidine(Spd) ryegrass cadmium(Cd) regulatory mechanism transcriptomics |
| DOI 10.13227/j.hjkx.20231040 |
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| 中文摘要 |
| 应用外源生长调节物质是增强植物抗逆能力的有效手段之一.以黑麦草为受试植物，进行水培试验，探究外源基施0.1 mmol ·L-1亚精胺（Spd）对不同水平（0、5和10 mg ·L-1）镉（Cd）胁迫下黑麦草根系生理学和分子生物学两方面的影响.生理学研究结果表明，Cd胁迫显著降低黑麦草根系的生理机能，而添加Spd可有效缓解Cd引起的负面作用.其中对根系可溶性蛋白含量的影响最为显著，较5 mg ·L-1和10 mg ·L-1 Cd单独处理，分别提高了90.91%和158.35%.Spd还通过提高抗坏血酸（ASA）和谷胱甘肽（GSH）含量、过氧化物酶（POD）活性来抑制氧化胁迫产物丙二醛（MDA）和过氧化氢（H2O2）的积累，对根系活力和超氧化物歧化酶（SOD）活性的影响则不显著.分子生物学研究结果表明，10 mg ·L-1Cd胁迫致使黑麦草根部大量基因发生了差异表达，应用外源Spd后差异表达基因的数目、差异显著性和差异倍数均显著降低，GO富集分析最显著的部分由响应有机环状化合物、醛基/酮基转移酶活性变为响应三价铁离子和2'-脱氧麦根酸2'-双加氧酶活性.单基因表达热图分析发现，外源Spd上调了锌铁转运蛋白和2'-脱氧麦根酸2'-双加氧酶相关基因的表达，提高了根系对铁的吸收利用能力.综上所述，施用一定浓度的Spd可有效调控黑麦草根系对Cd胁迫的响应，增强其耐性生理，减轻Cd的毒害效应. |
| 英文摘要 |
| The application of exogenous growth-regulating substances is an effective technique to enhance plant stress tolerance. Here, a hydroponic experiment was conducted to investigate the effects of exogenous basal application of 0.1 mmol·L-1 spermidine (Spd) on both the physiology and molecular biology of ryegrass root systems under varying degrees (0, 5, and 10 mg·L-1) of cadmium (Cd) stress using ryegrass as the test plants. The results of physiological studies revealed that Cd stress significantly reduced the physiological functions of the ryegrass root system, whereas the addition of Spd effectively alleviated the negative effects caused by Cd. The most significant effect was on the root soluble protein content, which increased by 90.91% and 158.35% compared with 5 mg·L-1and 10 mg·L-1 Cd alone. Spd also inhibited the accumulation of oxidative stress products malondialdehyde (MDA) and hydrogen peroxide (H2O2) by increasing the ascorbic acid (ASA) and glutathione (GSH) content and peroxidase (POD) activity, whereas the effects on root activity and superoxide dismutase (SOD) activity were not significant. The results of molecular biology studies demonstrated that 10 mg·L-1 Cd stress caused differential expression of a large number of genes in ryegrass roots, and the number of differentially expressed genes, differential significance, and differential multiplicity were significantly reduced after the application of exogenous Spd. The most significant part of the GO enrichment analysis shifted from responding to organic cyclic compounds and aldehyde/ketone group transferase activity to responding to trivalent iron ions and 2'-deoxymugineic-acid 2'-dioxygenase activity. Single gene expression heat map analysis revealed that exogenous Spd upregulated the expression of genes encoding zinc-iron transporter protein and 2'-deoxymugineic-acid 2'-dioxygenase, which improved the uptake and utilization of iron by the root system. In conclusion, the application of certain concentrations of Spd could effectively regulate the response of ryegrass roots to Cd stress, enhance its tolerance physiology, and mitigate the toxic effects of Cd. |
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