College of Agronomy, Northwest A&F University, State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China.
College of Agronomy, Northwest A&F University, State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China.
Plant Physiol Biochem. 2017 Sep;118:138-149. doi: 10.1016/j.plaphy.2017.06.014. Epub 2017 Jun 15.
Melatonin plays an important role in abiotic stress in plant, but its role in wheat drought tolerance is less known. To verify its role, wheat seedlings (Triticum aestivum L. 'Yan 995') at 60% and 40% of field capacity were treated with 500 μM melatonin in this study. Melatonin treatment significantly enhanced the drought tolerance of wheat seedlings, as demonstrated by decreased membrane damage, more intact grana lamella of chloroplast, higher photosynthetic rate, and maximum efficiency of photosystem II, as well as higher cell turgor and water holding capacity in melatonin-treated seedlings. Besides, melatonin markedly decreased the content of hydrogen peroxide and superoxide anion in melatonin-treated seedlings, which is attributed to the increased total antioxidant capacity, GSH and AsA contents, as well as enzyme activity including ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione peroxidase (GPX), and glutathione transferase (GST). The GSH-AsA related genes including APX, MDHAR, and DHAR were commonly upregulated by melatonin and correlated to the antioxidant enzyme activity as well as the content of GSH and AsA, indicating that the increase of GSH and AsA was attributed to the expression of these genes. Our result confirmed the mitigation potential of melatonin in drought stress and certain mechanisms of melatonin-induced GSH and AsA accumulation, which could deepen our understanding of melatonin-induced drought tolerance in wheat.
褪黑素在植物非生物胁迫中发挥着重要作用，但它在小麦抗旱性中的作用知之甚少。为了验证其作用，本研究在田间持水量的 60%和 40%条件下，用 500 μM 褪黑素处理小麦幼苗（Triticum aestivum L. 'Yan 995'）。褪黑素处理显著增强了小麦幼苗的抗旱性，表现为膜损伤减少，叶绿体基粒片层更完整，光合速率和光系统 II 的最大效率更高，以及细胞膨压和持水能力更高。此外，褪黑素明显降低了褪黑素处理幼苗中过氧化氢和超氧阴离子的含量，这归因于总抗氧化能力、GSH 和 AsA 含量以及包括抗坏血酸过氧化物酶 (APX)、单脱氢抗坏血酸还原酶 (MDHAR)、脱氢抗坏血酸还原酶 (DHAR)、谷胱甘肽过氧化物酶 (GPX) 和谷胱甘肽转移酶 (GST)在内的酶活性的增加。褪黑素共同上调了 GSH-AsA 相关基因包括 APX、MDHAR 和 DHAR，并与抗氧化酶活性以及 GSH 和 AsA 的含量相关，表明 GSH 和 AsA 的增加归因于这些基因的表达。我们的结果证实了褪黑素在干旱胁迫中的缓解潜力以及褪黑素诱导 GSH 和 AsA 积累的某些机制，这可以加深我们对小麦中褪黑素诱导抗旱性的理解。
