Abstract: The changes in activities of phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), peroxidase (POD), lipoxygenase (LOX), β-1,3-glucanase and chitinase in rice seedlings of susceptible variety pretreated with benzothiadiazole(BTH) and infected by M. grisea were analyzed to explore the physiological and biochemical mechanisms of the BTH induced systemic acquired resistance (SAR). Treatment of the third leaves of rice seedlings with BTH increased the activities of CAD, LOX and β-1,3-glucanase both in the third leaves and the upper untreated fourth leaves, showing systemic induction on the enzyme activity. After inoculation with M. grisea, the activities of CAD, POD, LOX and β-1,3-glucanase in the BTH treated third leaves and the upper untreated fourth leaves showed a more rapid and significant increase than those in the controls. No significant difference in the chitinase activity was observed between BTH treated and untreated seedlings after inoculation with the fungus, although pathogen infection increased markedly the enzyme activity. However, the PAL activity in the leaves did not show any remarkable changes upon BTH treatment and/or pathogen infection. The results suggested that the increased activities of CAD, POD, LOX and β 1,3 glucanase induced by BTH is most likely to be associated with the development of SAR in rice.

Key words: benzothiadiazole, Magnaporthe grisea, systemic acquired resistance, cinnamyl alcohol dehydrogenase, peroxidase, lipoxygenase, β-1, 3-glucanase

摘要： 分析了苯并噻二唑（BTH）诱导水稻对稻瘟病抗性中苯丙氨酸解氨酶（PAL）、肉桂醇脱氢酶（CAD）、过氧化物酶（POD）、脂氧合酶（LOX）、β-1,3-葡聚糖酶和几丁酶等活性的变化。结果表明BTH诱导处理亲和性水稻品种第3叶后提高了处理叶及其上位第4叶中CAD、LOX和β-1,3-葡聚糖酶等的活性；经BTH处理的幼苗接种稻瘟菌后，处理叶和其上位叶中CAD、POD、LOX和β-1,3-葡聚糖酶等活性快速增加，且增长幅度均显著大于对照。几丁酶活性在受稻瘟菌侵染后升高，但BTH诱导处理并不能促进其增加；PAL活性在BTH处理及稻瘟菌接种后均无明显变化。这些结果说明，BTH处理能诱导CAD、POD、LOX和β-1,3-葡聚糖酶等活性的增加，而且这些酶活性的升高可能与BTH诱发系统获得抗性的表现有关。

关键词: 苯并噻二唑, 稻瘟病, 诱导抗性, 肉桂醇脱氢酶, 过氧化物酶, 脂氧合酶, β-1, 3-葡聚糖酶