Department of Biology, Faculty of Science, Ege University, Bornova, 35100, Izmir, Turkey.
Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus, Denmark.
Plant Physiol Biochem. 2021 Oct;167:321-336. doi: 10.1016/j.plaphy.2021.08.016. Epub 2021 Aug 10.
Drought is a prevalent natural factor limiting crop production in arid regions across the world. To overcome this limitation, seeds are sown much deeper to boost germination by soil moisture produced by underground water. Seed pretreatment can effectively induce deep-sowing tolerance in plants. In the present study, we evaluated whether HO pretreatment of seeds can initiate metabolic changes and lead to improved deep-sowing tolerance in wheat. Pretreatment with 0.05 μM HO promoted first internode elongation by 13% in the deep-sowing tolerant wheat cultivar "Tir" and by 32% in the sensitive cultivar "Kıraç-66" under deep-sowing conditions, whereas internode elongation was inhibited by diphenyleneiodonium chloride. In contrast to Tir seedlings, HO levels in the first internode of Kıraç-66 seedlings increased under deep-sowing condition in the HO-treated group compared to controls. Moreover, these seedlings had significantly lower catalase (CAT), peroxidase (POX), and ascorbate peroxidase (APX) activities but higher NADPH oxidase (NOX) and superoxide dismutase (SOD) activities under the same conditions, which consequently induced greater HO accumulation. Contrary to Tir, both total glutathione and glutathione S-transferase (GST) activity decreased in Kıraç-66 after deep-sowing at 10 cm. However, HO treatment increased the total glutathione amounts and the activities of glutathione-related enzymes (except GST and GPX) in the first internode of Kıraç-66. Taken together, these data support that HO acts as a signaling molecule in the activation of antioxidant enzymes (specifically NOX, SOD, and CAT), regulation of both glutathione-related enzymes and total glutathione content, and upregulation of the cell wall-loosening protein gene TaEXPB23.
干旱是限制世界干旱地区作物生产的一种普遍自然因素。为了克服这一限制，种子被播种得更深，以利用地下水产生的土壤水分促进发芽。种子预处理可以有效地诱导植物的深播耐受性。在本研究中，我们评估了 HO 预处理种子是否可以引发代谢变化，并导致小麦深播耐受性的提高。0.05μM HO 预处理促进了深播耐受小麦品种“Tir”中第一节间伸长 13%，在敏感品种“Kıraç-66”中伸长 32%，而二苯碘氯则抑制了节间伸长。与 Tir 幼苗不同，在 HO 处理组中，与对照相比，深播条件下 Kıraç-66 幼苗第一节间的 HO 水平增加。此外，这些幼苗的过氧化氢酶 (CAT)、过氧化物酶 (POX) 和抗坏血酸过氧化物酶 (APX) 活性显著降低，而 NADPH 氧化酶 (NOX) 和超氧化物歧化酶 (SOD) 活性显著升高，从而导致 HO 积累增加。与 Tir 相反，在 10cm 深播后，Kıraç-66 的总谷胱甘肽和谷胱甘肽转移酶 (GST) 活性均降低。然而，HO 处理增加了 Kıraç-66 第一节间的总谷胱甘肽含量和谷胱甘肽相关酶 (除 GST 和 GPX 外) 的活性。总之，这些数据表明，HO 作为一种信号分子，激活了抗氧化酶（特别是 NOX、SOD 和 CAT），调节了谷胱甘肽相关酶和总谷胱甘肽含量，并上调了细胞壁疏松蛋白基因 TaEXPB23。
