Department of Chemical and Biology "A. Zambelli", University of Salermo, 84084, Fisciano, Salerno, Italy.
Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126, Milan, Italy.
Chemosphere. 2024 Aug;362:142642. doi: 10.1016/j.chemosphere.2024.142642. Epub 2024 Jun 20.
Chromium (Cr) is an highly toxic metal to plants and causes severe damage to their growth, development, and reproduction. Plant exposure to chronic and acute Cr stress treatments results in significant changes at short time in the gene expression profile and at long time in the genomic DNA methylation profile at a transgenerational level and, consequently, in gene expression. These epigenetic modifications and their implications imposed by the Cr stress are not yet completely known in plants. Herein, were identified the epigenetic changes induced by chronic and acute Cr stress treatments in Arabidopsis thaliana plants using Methylation Sensitive Amplification Polymorphism coupled with next-generation sequencing (MSAP-Seq). First-generation Arabidopsis plants (termed F0 plants) kept under hoagland solution were subjected to Cr stress treatments. For chronic Cr stress, plants were treated through hoagland solution with 2.5 μM Cr during the entire cultivation period until seed harvest. Meanwhile, for acute Cr stress, plants were treated with 5 μM Cr during the first three weeks and returned to unstressful control condition until seed harvest. Seeds from F0 plants were sown and F1 plants were re-submitted to the same Cr stress treatments. The seed germination rate was evaluated from F-2 seeds harvested of F1 plants kept under different Cr stress treatments (0, 10, 20, and 40 μM) compared to the unstressful control condition. These data showed significant changes in the germination rate of F-2 seeds originating from stressed F1 plants compared to F-2 seeds harvested from unstressful control plants. Given this data, F1 plants kept under these chronic and acute Cr stress treatments and unstressful control condition were evaluated for the transgenerational epigenetic modifications using MSAP-Seq. The MSAP-Seq data showed that several genes were modified in their methylation status as a consequence of chronic and acute Cr stress treatment to maintain plant defenses activated. In particular, RNA processing, protein translation, photorespiration, energy production, transmembrane transport, DNA transcription, plant development, and plant resilience were the major biological processes modulated by epigenetic mechanisms identified in F1 plants kept under chronic and acute Cr stress. Therefore, collective data suggested that Arabidopsis plants kept under Cr stress regulate their epigenetic status over generations based on DNA methylation to modulate defense and resilience mechanisms.
铬（Cr）是一种对植物具有高度毒性的金属，会对其生长、发育和繁殖造成严重损害。植物长期和短期暴露于慢性和急性 Cr 胁迫下，会导致基因表达谱在短时间内发生显著变化，在基因组 DNA 甲基化谱上发生长时间变化，并导致基因表达发生变化。这些表观遗传修饰及其对跨代水平基因表达的影响在植物中尚未完全阐明。在此，我们通过使用甲基化敏感扩增多态性结合下一代测序（MSAP-Seq），鉴定了拟南芥植物在慢性和急性 Cr 胁迫处理下诱导的表观遗传变化。第一代拟南芥植物（称为 F0 植物）在 Hoagland 溶液中培养，然后进行 Cr 胁迫处理。对于慢性 Cr 胁迫，植物在整个培养期间用含有 2.5μM Cr 的 Hoagland 溶液处理，直到收获种子。同时，对于急性 Cr 胁迫，植物在前三周用 5μM Cr 处理，然后返回无应激对照条件，直到收获种子。F0 植物的种子播种，F1 植物重新接受相同的 Cr 胁迫处理。从 F1 植物收获的 F2 种子在不同的 Cr 胁迫处理（0、10、20 和 40μM）下的种子发芽率与无应激对照条件下进行了比较。与无应激对照植物收获的 F2 种子相比，来自应激 F1 植物的 F2 种子的发芽率发生了显著变化。根据这些数据，对保持在慢性和急性 Cr 胁迫处理和无应激对照条件下的 F1 植物进行了 MSAP-Seq 分析，以评估跨代表观遗传修饰。MSAP-Seq 数据显示，由于慢性和急性 Cr 胁迫处理，许多基因的甲基化状态发生了改变，以维持植物防御机制的激活。特别是，RNA 加工、蛋白质翻译、光呼吸、能量产生、跨膜运输、DNA 转录、植物发育和植物弹性是在慢性和急性 Cr 胁迫下保持的 F1 植物中通过表观遗传机制调节的主要生物学过程。因此，综合数据表明，在 Cr 胁迫下，拟南芥植物通过 DNA 甲基化调节其表观遗传状态，以调节防御和弹性机制。
