Antifungal protein AMP produced by Streptomyces purpeofuscus YSSPG3 was purified from the fermentation. In order to reveal the anti-disease mechanism of AMP to hybrid bamboo blight,hybrid bamboo seedlings were treated with different concentrations of antifungal protein by spraying foliage or soaking root,and inoculated with or without Arthrinium phaeospermum. The effects of antifungal protein on disease index,and the major defense-related enzymes activities were investigated . The results showed that disease index of the bamboo seedlings treating with 10 times,20 times,and 50 times dilution of antifungal protein stock solution ( 360. 56 μg·mL -1 antifungal protein in the stock solution ) was significantly lower than the no-treatment control. After being induced by the antifungal protein,the defense-related enzymes activities of the seedlings,such as superoxide dismutase ( SOD) ,polyphenol oxidase ( PPO) ,peroxidase ( POD) ,catalase ( CAT) and phenylalanine ammonialyase (PAL),had different responses to the blight infection. The enzyme activities in the seedling leaves treated with both inducement by the antifungal protein and challenge inoculation with A. phaeospermum had a greater increase than those only treated with inducement. Regardless of challenge inoculation or not,the activities of SOD,PPO,POD,PPO,CAT and PAL in the leaves induced by the antifungal protein had the positive correlations with the concentration of the induced antifungal protein. Amplitude of sequential variation and increment of POD,PPO,CAT activities induced by soaking root was greater than that induced by spraying leaves; There was no significant difference in SOD and PAL between the two inducement methods. The correlation analysis showed that the PPO,POD and CAT activities induced by spraying leaves with antifungal protein had significant correlation with infection index. The SOD and PAL activities induced by soaking root with antifungal protein had significant correlation with infection index. It is suggested that the defense-related enzymes activities might have internal association with infection index.%从绛红褐链霉菌 YSSPG3发酵物中纯化获得抗菌蛋白 AMP，采用其稀释液喷雾或浸根诱导处理撑绿杂交竹苗，调查病情指数并测定杂交竹体内抗性相关酶活性的时序变化。结果表明：用抗菌蛋白 AMP(母液浓度为360.56μg·mL －1)的10，20，50倍稀释液叶片喷雾或浸根处理后，撑绿杂交竹病情指数都显著低于发病对照。经不同浓度抗菌蛋白诱导，植株内超氧化物歧化酶(SOD)、多酚氧化酶(PPO)、过氧化物酶(POD)、过氧化氢酶(CAT)和苯丙氨酸解氨酶( PAL)等抗性酶对杂交竹梢枯病菌有不同的响应。诱导并挑战接种处理的叶片内各抗性酶活性比只诱导不接种的处理上升幅度大。只诱导不接种及诱导后挑战接种，叶片内各抗性酶的活性与抗菌蛋白浓度呈正相关。POD，PPO，CAT 酶活性用浸根处理的时序变化幅度及同时期升高幅度大于喷雾处理，SOD，PAL的差异不明显。各抗性相关酶活性与病情指数的相关性分析表明，抗病性在喷雾诱导处理中与 PPO，POD 和 CAT 活性相关性显著，在浸根诱导处理中与 SOD和 PAL活性相关性显著，说明抗性酶与病情指数的变化存在内在的关联性。
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