State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, Zhejiang 311300, China.
State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, Zhejiang 311300, China.
J Hazard Mater. 2023 Oct 15;460:132274. doi: 10.1016/j.jhazmat.2023.132274. Epub 2023 Aug 19.
Aluminum (Al) toxicity is a significant constraint on agricultural productivity worldwide. Melatonin (MT) has been shown to alleviate Al toxicity in plants; however, the underlying mechanisms remain largely unknown. Here, we employed a combination of physiological and molecular biology techniques to examine the role of MT in mitigating Al toxicity of hickory. We found that MT decreased the contents of cell wall pectin, hemicellulose, Al, and Al-induced massive reactive oxygen species accumulation in the roots of hickory. Transcriptomic analysis revealed that MT may alleviate root tip Al stress by regulating Al-responsive and nonresponsive pathways. Co-expression regulatory network and dual-luciferase receptor assays revealed that transcription factors, CcC3H12 and CcAZF2, responded to MT and significantly activated the expression of two cell wall pectin-related genes, CcPME61 and CcGAE6, respectively. Further, yeast one-hybrid and electrophoretic mobility shift assay (EMSA) assays verified that CcC3H12 and CcAZF2 regulated CcPME61 and CcGAE6, respectively, by directly binding to their promoters. Overexpression of CcPME61 enhanced the Al sensitivity of Arabidopsis thaliana. Our results indicate that MT can improve Al tolerance of hickory via multiple pathways, which provides a new perspective for the study of the mechanism of MT in alleviating abiotic stress.
铝（Al）毒性是全球农业生产力的一个重大制约因素。褪黑素（MT）已被证明可减轻植物的 Al 毒性；然而，其潜在机制在很大程度上仍不清楚。在这里，我们采用了生理和分子生物学技术的组合，研究了 MT 在减轻山核桃 Al 毒性中的作用。我们发现 MT 降低了山核桃根部细胞壁果胶、半纤维素、Al 和 Al 诱导的大量活性氧积累的含量。转录组分析表明，MT 可能通过调节 Al 响应和非响应途径来减轻根尖 Al 胁迫。共表达调控网络和双荧光素酶受体测定表明，转录因子 CcC3H12 和 CcAZF2 对 MT 作出响应，并分别显著激活了两个细胞壁果胶相关基因 CcPME61 和 CcGAE6 的表达。此外，酵母单杂交和电泳迁移率变动分析（EMSA）实验验证了 CcC3H12 和 CcAZF2 通过直接结合其启动子分别调节 CcPME61 和 CcGAE6 的表达。CcPME61 的过表达增强了拟南芥对 Al 的敏感性。我们的结果表明，MT 可以通过多种途径提高山核桃的 Al 耐受性，为研究 MT 缓解非生物胁迫的机制提供了新的视角。
