Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia.
Plant Physiology Laboratory, Department of Botany, C.M.P. Degree College, A Constituent Post Graduate College of University of Allahabad, Prayagraj, India.
Physiol Plant. 2021 Sep;173(1):276-286. doi: 10.1111/ppl.13411. Epub 2021 May 5.
In this study, we have explored the possible role of ascorbic acid (ASC) and glutathione (GSH) in alleviating arsenate (As ) toxicity in brinjal roots. Moreover, we have also focused our attention on the possible involvement of endogenous nitric oxide (NO) in accomplishing this task. As treatment negatively impacts the length and fresh weight of roots and shoots as well as the dry weight and fitness of roots, and this was accompanied by greater As accumulation in roots and shoots of brinjal. As treatment also declined the endogenous NO level by inhibiting Nitric Oxide Synthase-like (NOS-like) activity. Furthermore, As stimulated oxidative stress markers, caused protein damage by their carbonylation due to downregulation in antioxidants [particularly ascorbate (AsA)-GSH cycle], leading to disturbed cellular redox status. This, collectively, led to root cell death in brinjal. However, the addition of either ASC or GSH rescued brinjal roots from the toxic effects of As in. Interestingly, lycorine (an inhibitor of ASC biosynthesis) further increased As toxicity, while ASC rescued its effects. Moreover, buthionine sulphoximine (BSO, an inhibitor of GSH biosynthesis) interestingly increased further As toxicity, while GSH rescued the plant from the As toxic effects. An interesting notion of this study was that GSH rescued the toxic effect of lycorine, while ASC rescued the toxic effect of BSO, though the As toxicity mediated by either ASC or GSH was always accompanied by high endogenous NO level and NOS-like activity. All together, these results suggest that ASC and GSH independently mitigate As toxicity in brinjal roots, but both might be dependent on endogenous NO for accomplishing the As toxicity alleviatory tasks.
在这项研究中，我们探讨了抗坏血酸（ASC）和谷胱甘肽（GSH）在缓解茄子根中砷酸盐（As）毒性中的可能作用。此外，我们还关注了内源性一氧化氮（NO）在完成这项任务中的可能作用。As 处理会对根和茎的长度和鲜重以及根的干重和活力产生负面影响，同时导致根和茎中 As 积累增加。As 处理还通过抑制一氧化氮合酶样（NOS-like）活性降低了内源性 NO 水平。此外，As 刺激氧化应激标志物，由于抗氧化剂（特别是抗坏血酸（AsA）-谷胱甘肽循环）的下调导致蛋白质羰基化而造成蛋白质损伤，导致细胞内氧化还原状态紊乱。这导致茄子根细胞死亡。然而，添加 ASC 或 GSH 均可使茄子根免受 As 的毒性影响。有趣的是，石蒜碱（ASC 生物合成的抑制剂）进一步增加了 As 的毒性，而 ASC 则挽救了其作用。此外，丁硫氨酸亚砜（BSO，GSH 生物合成的抑制剂）进一步增加了 As 的毒性，而 GSH 则使植物免受 As 的毒性影响。这项研究的一个有趣观点是，GSH 挽救了石蒜碱的毒性作用，而 ASC 则挽救了 BSO 的毒性作用，尽管 ASC 或 GSH 介导的 As 毒性总是伴随着高内源性 NO 水平和 NOS-like 活性。综上所述，这些结果表明 ASC 和 GSH 可独立缓解茄子根中的 As 毒性，但两者可能都依赖于内源性 NO 来完成减轻 As 毒性的任务。
