Laboratory of Plant Stress Responses, Faculty of Agriculture, Kagawa University, Ikenobe 2393 Kita Gun, Kagawa, Miki-Cho, 761-0795, Japan.
Department of Horticulture, Faculty of Agriculture, Sylhet Agricultural University, Sylhet, 3100, Bangladesh.
Environ Sci Pollut Res Int. 2023 Jul;30(32):78507-78520. doi: 10.1007/s11356-023-27993-0. Epub 2023 Jun 4.
Copper (Cu), an essential micronutrient, can generate reactive oxygen species (ROS) at its supra-optimal level in living cells as a transition metal, thus producing oxidative stress in plants. Therefore, protecting plants from Cu-induced oxidative stress via the exogenous application of chemical substances, particularly L-glutamic acid (L-Glu), could be a viable strategy for mitigating the toxicity of Cu. The aim of our present study was to investigate how ʟ-Glu protects lentil seedlings from oxidative stress produced by toxic Cu and allows them to survive under Cu toxicity. The results exhibited that when lentil seedlings were exposed to excessive Cu, their growth was inhibited and their biomass decreased due to an increase in Cu accumulation and translocation to the root, shoot, and leaves. Exposure to toxic Cu also depleted photosynthetic pigments, imbalanced water content, and other essential nutrients, increased oxidative stress, and reduced enzymatic and non-enzymatic antioxidants. However, pre-treatment of ʟ-Glu improved the phenotypic appearance of lentil seedlings, which was distinctly evidenced by higher biomass production, maintenance of water balance, and an increase in photosynthetic pigments when exposed to toxic Cu. ʟ-Glu also protected the seedlings from Cu-induced oxidative stress by reducing the oxidative stress marker, specifically by the efficient action of enzymatic and non-enzymatic antioxidants, particularly ascorbate, catalase, monodehydroascorbate, and glutathione peroxidase and maintaining redox balance. Furthermore, ʟ-Glu assisted in maintaining the homeostasis of Cu and other nutrient in the roots, shoots, and leaves of lentil. Collectively, our results provide evidence of the mechanism of ʟ-Glu-mediated protective role in lentil against Cu toxicity, thus proposed as a potential chemical for managing Cu toxicity not only in lentil but also other plants.
铜（Cu）作为一种过渡金属，在活细胞中超生理浓度下会产生活性氧（ROS），从而导致植物氧化应激。因此，通过外源施加化学物质，特别是 L-谷氨酸（L-Glu）来保护植物免受 Cu 诱导的氧化应激，可能是减轻 Cu 毒性的一种可行策略。本研究旨在探讨 L-Glu 如何保护小扁豆幼苗免受毒性 Cu 产生的氧化应激，并使它们能够在 Cu 毒性下存活。结果表明，当小扁豆幼苗暴露于过量 Cu 时，由于 Cu 积累和向根、茎和叶的转运增加，其生长受到抑制，生物量减少。暴露于毒性 Cu 还会耗尽光合色素，破坏水分平衡和其他必需养分，增加氧化应激，降低酶和非酶抗氧化剂。然而，L-Glu 的预处理改善了小扁豆幼苗的表型外观，这在暴露于毒性 Cu 时通过更高的生物量产生、水分平衡的维持和光合色素的增加得到明显证明。L-Glu 还通过减少氧化应激标志物来保护幼苗免受 Cu 诱导的氧化应激，特别是通过酶和非酶抗氧化剂（如抗坏血酸、过氧化氢酶、单脱氢抗坏血酸和谷胱甘肽过氧化物酶）的有效作用来维持氧化还原平衡。此外，L-Glu 有助于维持 Cu 和其他营养元素在小扁豆根、茎和叶中的内稳平衡。总之，我们的结果提供了 L-Glu 介导的小扁豆对 Cu 毒性保护作用的机制证据，因此被提议作为一种潜在的化学物质，不仅可以管理小扁豆，还可以管理其他植物的 Cu 毒性。
