Department of Biology, Ecology and Earth Science, University of Calabria, Arcavacata di Rende, CS, Italy.
Department of Agriculture, Food and Environment, University of Pisa, Pisa, PI, Italy.
Sci Rep. 2021 May 26;11(1):10965. doi: 10.1038/s41598-021-90528-5.
DNA methylation plays an important role in modulating plant growth plasticity in response to stress, but mechanisms involved in such control need further investigation. We used drm1 drm2 cmt3 mutant of Arabidopsis thaliana, defective in DNA methylation, to explore metabolic pathways downstream epigenetic modulation under cadmium (Cd) stress. To this aim, a transcriptomic analysis was performed on ddc and WT plants exposed to a long-lasting (21 d) Cd treatment (25/50 µM), focusing on hormone genetic pathways. Growth parameters and hormones amount were also estimated. Transcriptomic data and hormone quantification showed that, under prolonged Cd treatment, level and signalling of growth-sustaining hormones (auxins, CKs, GAs) were enhanced and/or maintained, while a decrease was detected for stress-related hormones (JA, ABA, SA), likely as a strategy to avoid the side effects of their long-lasting activation. Such picture was more effective in ddc than WT, already at 25 µM Cd, in line with its better growth performance. A tight relationship between methylation status and the modulation of hormone genetic pathways under Cd stress was assessed. We propose that the higher genome plasticity conferred to ddc by DNA hypomethylated status underlies its prompt response to modulate hormones genetic pathways and activity and assure a flexible growth.
DNA 甲基化在调节植物对胁迫的生长可塑性方面起着重要作用，但这种控制的机制仍需要进一步研究。我们使用拟南芥中 DNA 甲基化缺陷的 drm1 drm2 cmt3 突变体，来探索在镉（Cd）胁迫下，表观遗传调控下游的代谢途径。为此，我们对暴露于长时间（21 天）Cd 处理（25/50 µM）下的 ddc 和 WT 植物进行了转录组分析，重点关注激素遗传途径。我们还估计了生长参数和激素含量。转录组数据和激素定量结果表明，在长时间 Cd 处理下，维持生长的激素（生长素、细胞分裂素、赤霉素）的水平和信号增强和/或维持，而与应激相关的激素（JA、ABA、SA）则下降，这可能是避免其长期激活的副作用的一种策略。这种情况在 ddc 中比 WT 更明显，在 25 µM Cd 时就已经如此，这与其更好的生长表现一致。我们评估了在 Cd 胁迫下，甲基化状态与激素遗传途径调节之间的紧密关系。我们提出，ddc 中 DNA 低甲基化状态赋予其更高的基因组可塑性，这是其快速响应并调节激素遗传途径和活性的基础，从而保证了灵活的生长。
