【作者】 刘桂英；

【导师】 朱昌雄； 蒋细良；

【作者基本信息】 中国农业科学院 ， 微生物学， 2004， 硕士

【摘要】 中生菌素是一种防治水稻白叶枯病非常有效的农用抗生素类生物农药。本实验对中生菌素介导的水稻悬浮细胞与白叶枯病菌互作中，三种主要防御酶POD、PPO、PAL活性及POD、PPO同工酶的动态变化进行了研究。结果如下： (一)建立了粳稻品种感病品系沈农1033及其携带Xa-4抗病基因的近等位基因系CBB4的愈伤组织、胚性悬浮细胞系。 (二)中生菌素对水稻悬浮细胞主要防御酶酶活性的影响：(1)5mg／l、10mg／l、15mg／l的中生菌素处理水稻悬浮细胞后，72h POD活性达高峰时，1033中POD活性比空白对照分别增加了111.1％、151.5％、182.1％，CBB4中POD活性比空白对照分别增加了189.8％、178.2％、224.2％；24h PPO活性达高峰时，1033中PPO活性比空白对照分别增加了150.9％、189.2％、171.9％，CBB4中PPO活性比空白对照分别增加了98.7％、181.8％、93.4％；48h PAL活性达高峰时，1033中PAL活性比空白对照分别增加了121.1％、139.7％、135.4％，CBB4中PAL活性比空白对照分别增加了128.8％、143.6％、141.2％。以上结果说明5mg／l、10mg／l、15mg／l的中生菌素对抗、感水稻悬浮细胞中POD、PPO、PAL均具有诱导作用，且对CBB4中POD、PAL的诱导效果较1033好，对PPO的诱导效果则是1033比CBB4好：在三种处理浓度中，15mg／l的中生菌素对POD的诱导效果较好，10mg／l对PPO和PAL的诱导效果较好。 (2)中生菌素作用于抗、感水稻悬浮细胞后，POD、PPO、PAL活性与空白对照相比均呈先升后降趋势，24～72h，PPO、PAL、POD活性相继上升到最大值，POD增加幅度最大，PAL次之，PPO则最小。 (三)中生菌素对水稻胚性悬浮细胞主要防御酶同工酶的影响： (1)POD同工酶谱带变化：经中生菌素处理后，无论抗、感水稻悬浮细胞接菌与否，a区谱带基本不变；b区中b2、b4带变化较大，b1、b3带虽有变化，但变化不大：c区中，主要是c1、c2带的变化，c3带的变化也不大，说明中生菌素可诱导或增强b2、b3、c1、c2、c3带POD同工酶谱带的表达。 (2)PPO同工酶谱带变化：在中生菌素作用下，无论抗、感水稻悬浮细胞接菌与否，a区PPO同工酶谱带变化较大，a1、a3存在增强现象．a2带存在减弱现象；b区中酶带变化较大，酶带存在减弱或消失现象；c区中谱带变化也不大，c1、c2带基本无变化，c3带存在增强现象，说明中生菌素可诱导或增强a3、b1、c1带PPO同工酶谱带的表达。 以上结果说明，中生菌素能诱导植物防御酶系中重要成员POD、PPO、PAL的表达，从而诱导植物防御反应和系统获得抗性的发生，增强植物的抗病性。 本研究可为中生菌素作用机制的阐明及适时、适量的田间应用和农抗筛选模型的建立提供理论指导。更多还原

【Abstract】 Zhongshengmycin is a new promising and commercially available agricultural antibiotic. However the mode of action of Zhongshengmycin was not completely understood at present.The systematic dynamic characteristics of pexoxidase(POD) and its isozyme, polypheno! oxidase(PPO) and its isozyme, phenylalanine ammonnialyase(PAL) were studied in suspension-cultured cells of the near-isogenic lines for bacterial blight resistance of rice which were inoculated with Xanthomonas oryzae and treated with different concentrations of Zhongshengmycin. The results are listed as follow:(1) A system of callus induction from mature rice seeds and suspension culture of the near-isogenic lines for bacterial blight resistance of rice cells were set up.(2) Systemic induction of several defense enzymes in suspension-cultured cells of rice inoculated with Xanthomonas oryzae pv. oryzae and Zhongshengmycin was determined. After being treated with Xanthomonas oryzae and Zhongshengmycin, the activity of POD, PPO, PAL in suspension-cultured cells of rice were higher than the control. The results indicated that Zhongshengmycin can induce the expression of these defense enzymes respectively in suspension-cultured cells of rice. For POD , the optimum concentration of Zhongshengmycin is 15mg/l. However, for PPO and PAL, the optimum concentration of Zhongshengmycin is 10mg/l; and the induction of POD, PAL expression in susceptible rice cultivar Shennong 1033 was generally lower than in resistant rice cultivar CBB4, but the induction of PPO expression in CBB4 was generally lower than in Shennong 1033. The results showed that the induction of POD, PPO, PAL expression in suspension-cultured cells of rice was positively related to rice resistance to bacterial blight disease, and could be used as the indicators of rice resistance to bacterial blight disease.(3) Electrophoretic isozyme zymogram patterns of POD, PPO in suspension-cultured cells of rice treated with Xanthomonas oryzae and with Zhongshengmycin were studied. After inoculation with Xanthomonas oryzae, the systematiec dynamic characteristics of POD and PPO isozyme were determined. The results demonstrated that Zhongshengmycin can induce the expression of POD, PPO in suspension-cultured cells of rice, which were identified by the thickening of the original isozyme bands and the expression of some new isozyme bands.And these changed bands were related to a marked increase of the over-all enzyme activity.This thesis could not only help us to understand the mode of action of Zhongshengmycin, but also provide information for the method of screening new bactericides.更多还原