Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.
Plant Physiology Laboratory, Department of Botany, C.M.P. Degree College, A Constituent Post Graduate College of University of Allahabad, Prayagraj, 211002, India.
Physiol Plant. 2021 Sep;173(1):45-57. doi: 10.1111/ppl.13168. Epub 2020 Aug 17.
Metal toxicity in crop plants is a matter of scientific concern. Therefore, in recent years efforts have been made to minimize metal toxicity in crop plants. Out of various strategies, priming of seedlings with certain chemicals, like e.g. donors of signaling molecules, nutrients, metabolites or plant hormones has shown encouraging results. However, mechanisms related with the priming-induced mitigation of metal toxicity are still poorly known. Hence, we have tested the potential of 2-oxoglutarate (2-OG) priming in enhancing the arsenate (As ) toxicity tolerance in tomato seedlings along with deciphering the probable role of nitric oxide (NO) in accomplishing this task. Arsenate decreased growth, endogenous NO and nitric oxide synthase-like activity but enhanced the accumulation of As, which collectively led to root cell death. Arsenate toxicity also decreased some photosynthetic characteristics (i.e. F /F qP, F /F and F /F , and total chlorophyll content) but enhanced NPQ. However, priming with 2-OG alleviated the toxic effect of As on growth, endogenous NO, cell death and photosynthesis. Moreover, arsenate inhibited the activities of enzymes of nitrogen metabolism (i.e. nitrate reductase, nitrite reductase, glutamine synthetase and glutamine 2-oxoglutarate aminotransferase) but increased the activity of glutamate dehydrogenase and NH content. Superoxide radicals, hydrogen peroxide, lipid peroxidation, protein oxidation and membrane damage increased upon As exposure, but the antioxidant enzymes (i.e. superoxide dismutase, catalase and glutathione-S-transferase) showed differential responses. Overall, our results showed that 2-OG is capable of alleviating As toxicity in tomato seedlings but the involvement of endogenous NO is probably required.
金属毒性在农作物中是一个科学关注的问题。因此，近年来人们努力将作物中的金属毒性降到最低。在各种策略中，用某些化学物质如信号分子、营养物质、代谢物或植物激素的供体对幼苗进行预处理已显示出令人鼓舞的结果。然而，与诱导减轻金属毒性相关的机制仍知之甚少。因此，我们测试了 2-氧戊二酸（2-OG）预处理在增强番茄幼苗对砷酸盐（As）毒性耐受性方面的潜力，并揭示了一氧化氮（NO）在完成这一任务中的可能作用。砷酸盐会降低生长、内源性一氧化氮和一氧化氮合酶样活性，但会增加砷的积累，这共同导致根细胞死亡。砷酸盐毒性还降低了一些光合作用特性（即 F/F qP、F/F 和 F/F ，以及总叶绿素含量），但增强了 NPQ。然而，用 2-OG 预处理可以减轻 As 对生长、内源性 NO、细胞死亡和光合作用的毒性作用。此外，砷酸盐抑制氮代谢酶（如硝酸还原酶、亚硝酸还原酶、谷氨酰胺合成酶和谷氨酰胺 2-氧戊二酸氨基转移酶）的活性，但增加谷氨酸脱氢酶和 NH 的活性。超氧自由基、过氧化氢、脂质过氧化、蛋白质氧化和膜损伤在 As 暴露时增加，但抗氧化酶（如超氧化物歧化酶、过氧化氢酶和谷胱甘肽-S-转移酶）表现出不同的反应。总的来说，我们的结果表明，2-OG 能够减轻番茄幼苗中的 As 毒性，但可能需要内源性 NO 的参与。
