MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China.
Plant Physiol Biochem. 2013 Sep;70:278-86. doi: 10.1016/j.plaphy.2013.05.042. Epub 2013 Jun 6.
Flooding of soils often results in hypoxic conditions surrounding plant roots, which is a harmful abiotic stress to crops. Hydrogen sulfide (H2S) is a highly diffusible, gaseous molecule that modulates cell signaling and is involved in hypoxia signaling in animal cells. However, there have been no previous studies of H2S in plant cells in response to hypoxia. The effects of H2S on hypoxia-induced root tip death were studied in pea (Pisum sativum) via analysis of endogenous H2S and reactive oxygen species (ROS) levels. The activities of key enzymes involved in antioxidative and H2S metabolic pathways were determined using spectrophotometric assays. Ethylene was measured by gas chromatography. We found that exogenous H2S pretreatment dramatically alleviated hypoxia-induced root tip death by protecting root tip cell membranes from ROS damage induced by hypoxia and by stimulating a quiescence strategy through inhibiting ethylene production. Conversely, root tip death induced by hypoxia was strongly enhanced by inhibition of the key enzymes responsible for endogenous H2S biosynthesis. Our results demonstrated that exogenous H2S pretreatment significantly alleviates hypoxia-induced root tip death in pea seedlings and, therefore, enhances the tolerance of the plant to hypoxic stress.
土壤淹水通常会导致植物根系周围缺氧，这对作物是一种有害的非生物胁迫。硫化氢（H2S）是一种具有高扩散性的气态分子，可调节细胞信号转导，并参与动物细胞中的缺氧信号转导。然而，以前没有研究过 H2S 在植物细胞对缺氧的反应。本研究通过分析内源 H2S 和活性氧（ROS）水平，研究了 H2S 对豌豆（Pisum sativum）根尖缺氧死亡的影响。使用分光光度法测定了参与抗氧化和 H2S 代谢途径的关键酶的活性。通过气相色谱法测定了乙烯的含量。我们发现，外源 H2S 预处理通过保护根尖细胞膜免受缺氧引起的 ROS 损伤和通过抑制乙烯生成来刺激静止策略，从而显著减轻缺氧引起的根尖死亡。相反，抑制负责内源性 H2S 生物合成的关键酶强烈增强了缺氧引起的根尖死亡。我们的研究结果表明，外源 H2S 预处理可显著减轻豌豆幼苗缺氧引起的根尖死亡，从而增强植物对缺氧胁迫的耐受性。
