Institute of Crop Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, China.
J Integr Plant Biol. 2009 Dec;51(12):1104-15. doi: 10.1111/j.1744-7909.2009.00879.x.
The activity of plasma membrane (PM) nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and its catalytic properties in rice was investigated under drought stress conditions. Drought stress led to decreased leaf relative water content (RWC) and, as a result of drought-induced oxidative stress, the activities of antioxidant enzymes increased significantly. More interestingly, the intensity of applied water stress was correlated with increased production of H2O2 and O2 (-) and elevated activity of PM NADPH oxidase, a key enzyme of reactive oxygen species generation in plants. Histochemical analyses also revealed increased H2O2 and O2 (-) production in drought-stressed leaves. Application of diphenylene iodonium (DPI), an inhibitor of PM NADPH oxidase, did not alleviate drought-induced production of H2O2 and O2 (-). Catalysis experiments indicated that the rice PM NADPH oxidase was partially flavin-dependent. The pH and temperature optima for this enzyme were 9.8 and 40 degrees C, respectively. In addition, drought stress enhanced the activity under alkaline pH and high temperature conditions. These results suggest that a complex regulatory mechanism, associated with the NADPH oxidase-H2O2 system, is involved in the response of rice to drought stress.
研究了干旱胁迫条件下水稻质膜（PM）烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶的活性及其催化特性。干旱胁迫导致叶片相对水含量（RWC）降低，由于干旱诱导的氧化应激，抗氧化酶活性显著增加。更有趣的是，施加的水分胁迫强度与 H2O2 和 O2 (-) 的产生增加以及 PM NADPH 氧化酶活性升高有关，PM NADPH 氧化酶是植物中活性氧生成的关键酶。组织化学分析还表明，干旱胁迫叶片中 H2O2 和 O2 (-) 的产生增加。应用 PM NADPH 氧化酶抑制剂二苯基碘（DPI）不能减轻干旱诱导的 H2O2 和 O2 (-) 的产生。催化实验表明，水稻 PM NADPH 氧化酶部分依赖黄素。该酶的 pH 和温度最适值分别为 9.8 和 40°C。此外，干旱胁迫增强了在碱性 pH 和高温条件下的活性。这些结果表明，与 NADPH 氧化酶-H2O2 系统相关的复杂调控机制参与了水稻对干旱胁迫的响应。
