Ecotoxicogenomics Lab, Department of Biotechnology, Jamia Millia Islamia, New Delhi, 110025, India.
Department of Biochemistry, University of Nebraska-Lincoln, Beadle Center, Lincoln, NE, 68503, USA.
Environ Sci Pollut Res Int. 2020 Apr;27(11):11697-11713. doi: 10.1007/s11356-019-07520-w. Epub 2020 Jan 23.
The present study was designed to see the influence of selenium (Se) and sulphur (S) in the alleviation of arsenic (As)-induced stress in Brassica juncea plant. Se-induced alterations in physiological and biochemical responses due to deficient S (DS), normal S (NS) and additional S (AS) conditions were evaluated in 14-day-old seedlings of B. juncea variety Varuna. During the last 7 days of the 14-day-old seedlings, supplementation with arsenite (As, 300 μM) alone and its combination with selenite (Se, 50 μM) along with different S treatments was done which are as follows: (i) control; (ii) As; (iii) As+Se+DS; (iv) As+Se + NS; (v) As+Se + AS. Experimental results showed that the application of AS in spite of NS supplied with Se influenced plant growth, oxidative stress and thiol-ascorbate-related parameters more prominently under As stress. The plants with As+Se+AS treatment exhibited lower ROS (superoxide and hydrogen peroxide ion), malondialdehyde (MDA) accumulation and lipoxygenase activity with increased activities of superoxide dismutase, catalase and ascorbate peroxidase compared with As+Se+NS condition. These plants also exhibited an increase in cysteine, non-protein thiols and phytochelatins, along with reduced, oxidised and redox content of glutathione and ascorbate. Furthermore, the application of S along with Se increased the activities of glutathione reductase, glutathione S-transferase, glutathione peroxidase, monodehydroascorbate and dehydroascorbate to minimise As stress. However, we observed that these responses were reversed under As+Se+DS condition and induced oxidative stress, which was almost similar to As only treatment. It indicated that AS nutrition potentiated Se to alleviate As-inhibited plant growth by modulating antioxidants including thiol-ascorbate-based mechanism and reducing As accumulation in B. juncea plants.
本研究旨在观察硒 (Se) 和硫 (S) 在缓解蕈菜植物砷 (As) 胁迫中的影响。在 14 天大的蕈菜品种 Varuna 幼苗中，评估了 Se 诱导的由于缺 S (DS)、正常 S (NS) 和额外 S (AS) 条件下的生理和生化反应的变化。在 14 天大的幼苗的最后 7 天中，单独补充亚砷酸盐 (As，300 μM) 及其与亚硒酸盐 (Se，50 μM) 的组合以及不同 S 处理一起进行，如下所示：(i) 对照；(ii) As；(iii) As+Se+DS；(iv) As+Se+NS；(v) As+Se+AS。实验结果表明，尽管 NS 中添加了 Se，但在 As 胁迫下，AS 的应用更明显地影响了植物的生长、氧化应激和巯基-抗坏血酸相关参数。与 As+Se+NS 条件相比，具有 As+Se+AS 处理的植物表现出较低的 ROS（超氧阴离子和过氧化氢离子）、丙二醛 (MDA) 积累和脂氧合酶活性，同时具有较高的超氧化物歧化酶、过氧化氢酶和抗坏血酸过氧化物酶活性。这些植物还表现出半胱氨酸、非蛋白巯基和植物螯合肽的增加，以及谷胱甘肽和抗坏血酸的还原、氧化和氧化还原含量的降低。此外，S 与 Se 的联合应用增加了谷胱甘肽还原酶、谷胱甘肽 S-转移酶、谷胱甘肽过氧化物酶、单脱氢抗坏血酸和脱氢抗坏血酸的活性，以最小化 As 胁迫。然而，我们观察到在 As+Se+DS 条件下这些反应被逆转，并诱导了氧化应激，这与仅用 As 处理几乎相似。这表明，AS 营养增强了 Se 缓解 As 抑制蕈菜植物生长的作用，其机制是通过调节抗氧化剂，包括巯基-抗坏血酸为基础的机制，并减少蕈菜植物中的 As 积累。
