褪黑素通过减轻氧化损伤和减少重金属积累来增强辣椒对重金属胁迫的耐受性。
Melatonin enhanced the heavy metal-stress tolerance of pepper by mitigating the oxidative damage and reducing the heavy metal accumulation.
机构信息
Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China; Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Horticulture, Hainan University, Haikou 570228, China; Hainan Yazhou Bay Seed Laboratory, Sanya 572025, China.
Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, Sanya Nanfan Research Institute, Hainan University, Sanya 572025, China; Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Horticulture, Hainan University, Haikou 570228, China.
出版信息
J Hazard Mater. 2023 Jul 15;454:131468. doi: 10.1016/j.jhazmat.2023.131468. Epub 2023 Apr 23.
Heavy metals (HMs), like vanadium (V), chromium (Cr), cadmium (Cd), and nickel (Ni) toxicity due to anthropogenic, impair plant growth and yield, which is a challenging issue for agricultural production. Melatonin (ME) is a stress mitigating molecule, which alleviates HM-induced phytotoxicity, but the possible underlying mechanism of ME functions under HMs' phytotoxicity is still unclear. Current study uncovered key mechanisms for ME-mediated HMs-stress tolerance in pepper. HMs toxicity greatly reduced growth by impeding leaf photosynthesis, root architecture system, and nutrient uptake. Conversely, ME supplementation markedly enhanced growth attributes, mineral nutrient uptake, photosynthetic efficiency, as measured by chlorophyll content, gas exchange elements, chlorophyll photosynthesis genes' upregulation, and reduced HMs accumulation. ME treatment showed a significant decline in the leaf/root V, Cr, Ni, and Cd concentration which was about 38.1/33.2%, 38.5/25.9%, 34.8/24.9%, and 26.6/25.1%, respectively, when compared with respective HM treatment. Furthermore, ME remarkably reduced the ROS (reactive oxygen species) accumulation, and reinstated the integrity of cellular membrane via activating antioxidant enzymes (SOD, superoxide dismutase; CAT, catalase; APX, ascorbate peroxidase; GR, glutathione reductase; POD, peroxidase; GST, glutathione S-transferase; DHAR, dehydroascorbate reductase; MDHAR, monodehydroascorbate reductase) and as well as regulating ascorbate-glutathione (AsA-GSH) cycle. Importantly, oxidative damage showed efficient alleviations through upregulating the genes related to key defense such as SOD, CAT, POD, GR, GST, APX, GPX, DHAR, and MDHAR; along with the genes related to ME biosynthesis. ME supplementation also enhanced the level of proline and secondary metabolites, and their encoding genes expression, which may control excessive HO (hydrogen peroxide) production. Finally, ME supplementation enhanced the HM stress tolerance of pepper seedlings.
重金属（HMs），如钒（V）、铬（Cr）、镉（Cd）和镍（Ni），由于人为因素而产生毒性，会损害植物的生长和产量，这是农业生产面临的一个挑战。褪黑素（ME）是一种减轻压力的分子，它可以减轻 HM 引起的植物毒性，但 ME 在 HM 植物毒性下的作用的潜在机制尚不清楚。本研究揭示了 ME 介导的辣椒对 HM 胁迫耐受的关键机制。HM 毒性通过阻碍叶片光合作用、根系结构系统和养分吸收，极大地降低了植物的生长。相反，ME 补充剂显著增强了生长特性、矿物质养分吸收、光合作用效率，表现为叶绿素含量、气体交换元素、叶绿素光合作用基因的上调以及减少 HM 积累。ME 处理后，叶片/根中 V、Cr、Ni 和 Cd 的浓度显著下降，分别约为 38.1/33.2%、38.5/25.9%、34.8/24.9%和 26.6/25.1%，与各自的 HM 处理相比。此外，ME 通过激活抗氧化酶（SOD、超氧化物歧化酶；CAT、过氧化氢酶；APX、抗坏血酸过氧化物酶；GR、谷胱甘肽还原酶；POD、过氧化物酶；GST、谷胱甘肽 S-转移酶；DHAR、脱氢抗坏血酸还原酶；MDHAR、单脱氢抗坏血酸还原酶）以及调节抗坏血酸-谷胱甘肽（AsA-GSH）循环，显著减少 ROS（活性氧）的积累，恢复细胞膜的完整性。重要的是，通过上调与关键防御相关的基因，如 SOD、CAT、POD、GR、GST、APX、GPX、DHAR 和 MDHAR，以及与 ME 生物合成相关的基因，有效地缓解了氧化损伤。ME 补充剂还增强了脯氨酸和次生代谢物的水平及其编码基因的表达，这可能控制过量 HO（过氧化氢）的产生。最后，ME 补充剂增强了辣椒幼苗对 HM 胁迫的耐受性。
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