College of Chemistry and Chemical Engineering, JinzhongUniversity, Yuci, China.
School of Life Science, Shanxi University, Taiyuan, China.
Ecotoxicol Environ Saf. 2021 Jan 1;207:111248. doi: 10.1016/j.ecoenv.2020.111248. Epub 2020 Sep 11.
Drought is one of the most common factors that limit plant growth and productivity. Sulfur dioxide (SO) has recently been found to play a benefical role in protection of plants against environmental stress. In this study, we investigated the effect of SO on the physiological and molecular response of wheat seedlings to drought stress. Pretreatment with 10 mg/m SO significantly increased the survival rate and relative water content (RWC) of wheat seedlings under drought stress, indicating that pre-exposure to appropriate level of SO could enhance drought tolerance of plants. These responses were related to the enhanced proline accumulation in the drought-treated wheat seedlings that induced by SO pretreatment. Meanwhile, SO pretreatment increased the activities of superoxide dismutase (SOD) and peroxidase (POD), and effectively reduced the content of hydrogen peroxide (HO) and malondialdehyde (MDA) in drought-treated wheat seedlings, suggesting SO could alleviate drought-induced oxidative damage by enhancing antioxidant defense system in plants. Expression analysis of transcription factor genes also showed that SO pretreatment decreased the expression of TaNAC69, but the expression of TaERF1 and TaMYB30 changed slightly and maintained at higher levels in wheat seedlings in response to drought stress. Furthermore, SO pretreatment triggered marked accumulation of hydrogen sulfide (HS) in wheat seedlings under drought stress. When scavenged HS by spraying Hypotaurine (HT), the activities of antioxidant enzymes and the expression of transcription factor genes were decreased, and the content of HO and MDA increased to the level of drought treatment alone, suggesting a regulatory role of SO-induced HS in plant adaptation to drought stress. Together, this study indicated that SO enhanced drought tolerance of wheat seedlings through HS signaling, and provided new strategy for enhancing plant tolerance to drought stress.
干旱是限制植物生长和生产力的最常见因素之一。最近发现，二氧化硫 (SO) 在保护植物免受环境胁迫方面发挥有益作用。在这项研究中，我们研究了 SO 对小麦幼苗应对干旱胁迫的生理和分子响应的影响。10mg/m SO 的预处理显着提高了干旱胁迫下小麦幼苗的存活率和相对水含量 (RWC)，表明适当水平的 SO 预先暴露可以增强植物的耐旱性。这些反应与 SO 预处理诱导的干旱处理小麦幼苗中脯氨酸积累增加有关。同时，SO 预处理增加了超氧化物歧化酶 (SOD) 和过氧化物酶 (POD) 的活性，并有效降低了干旱处理小麦幼苗中过氧化氢 (HO) 和丙二醛 (MDA) 的含量，表明 SO 可以通过增强抗氧化防御系统来减轻干旱诱导的氧化损伤。转录因子基因的表达分析也表明，SO 预处理降低了 TaNAC69 的表达，但 TaERF1 和 TaMYB30 的表达略有变化，并在小麦幼苗中保持较高水平以响应干旱胁迫。此外，SO 预处理在干旱胁迫下引发小麦幼苗中大量的硫化氢 (HS) 积累。当用 Hypotaurine (HT) 喷洒清除 HS 时，抗氧化酶的活性和转录因子基因的表达降低，HO 和 MDA 的含量增加到单独干旱处理的水平，表明 SO 诱导的 HS 在植物适应干旱胁迫中起调节作用。总之，这项研究表明，SO 通过 HS 信号增强了小麦幼苗的耐旱性，为增强植物对干旱胁迫的耐受性提供了新策略。
