Soil cadmium pollution has increasingly become a serious problem for crop production, which drastically attenuates plant growth and food safety. Although N6-methyladenosine (m6A) methylation is crucial for plant response to various stresses, the regulatory mechanism underlying m6A modification during cadmium (Cd) stress remains unclear. This study investigated the physiological responses, transcriptome-wide m6A methylome, and proteome changes in tomato roots exposed to 50 μmol · L−1 CdCl2. Excess Cd restricted plant growth, altered the antioxidant system and disrupted mineral nutrient absorption. We identified a negative correlation between m6A levels and gene transcription for 150 out of 198 differentially expressed genes (DEGs) that were hypomethylated but mRNA up-regulated. Cd stress also enhanced translational efficiency, particularly for differentially abundant proteins (DAPs). Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that differentially m6A modified genes (DMGs), DEGs, and DAPs were commonly enriched in phenylpropanoid biosynthesis, glutathione metabolism, and ABC transporters, reflecting cell wall barriers, chelation, and transport of Cd, respectively. Finally, we confirmed the Cd-transport activity of eight putative metal transporters identified in DMGs, DEGs, or DAPs by yeast complementaion experiments, and pharmacologically investigated the effect of m6A modification on their expression. Treatment with the m6A methylation inhibitor 3-deazaneplanocin A (3-DA) reduced SlIRT1/2 expression and increased SlNRAMP3/SlZIP4 expression, while the m6A demethylase inhibitor meclofenamic acid (MA) treatment decreased SlNRAMP3 expression but elevated SlIRT2 expression under Cd stress. Our findings provide novel insights into the interplay between m6A modification, transcription, and translation under Cd stress and the associated plant stress response.

中文翻译：

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综合生理学、转录组范围的 m6A 甲基化和蛋白质组分析揭示了番茄根系对镉胁迫反应的分子机制


土壤镉污染日益成为农作物生产面临的严重问题，大大削弱了植物生长和食品安全。尽管 N6-甲基腺苷 （m6A） 甲基化对植物对各种胁迫的反应至关重要，但在镉 （Cd） 胁迫期间 m6A 修饰的调控机制仍不清楚。本研究调查了暴露于 50 μmol ·L-1 氯化镉 2. 过量的 Cd 限制了植物的生长，改变了抗氧化系统并破坏了矿物养分的吸收。我们确定了 198 个差异表达基因 （DEG） 中 150 个的 m6A 水平与基因转录呈负相关，这些基因是低甲基化但 mRNA 上调的。Cd 应激还提高了翻译效率，特别是对于差异丰度蛋白 （DAP）。京都基因与基因组百科全书 （KEGG） 分析显示，差异 m6A 修饰基因 （DMG）、DEGs 和 DAPs 通常富集于苯丙烷类生物合成、谷胱甘肽代谢和 ABC 转运蛋白，分别反映细胞壁屏障、螯合和 Cd 的转运。最后，我们通过酵母互补实验证实了在 DMGs、DEGs 或 DAPs 中鉴定的 8 种推定金属转运蛋白的 Cd 转运活性，并药理学研究了 m6A 修饰对其表达的影响。用 m6A 甲基化抑制剂 3-deazaneplanocin A （3-DA） 处理降低了 SlIRT1/2 表达并增加了 SlNRAMP3/SlZIP4 表达，而 m6A 去甲基化酶抑制剂甲氯芬那酸 （MA） 处理降低了 SlNRAMP3 表达，但在 Cd 应激下提高了 SlIRT2 表达。 我们的研究结果为 Cd 胁迫下 m6A 修饰、转录和翻译与相关植物胁迫反应之间的相互作用提供了新的见解。