油菜菌核病菌致病力与纤维素酶活性关系的初步研究

Preliminary Study on the Relationship between Pathogenicity and Cellulase Activity of Sclerotinia sclerotiorum Isolates

采用牙签菌丝体接种法,测定了来自安徽省桐城、无为、宁国、旌德、寿县,等5个市县的24个油菜菌核病菌菌株对油菜的致病力,结果表明,供试油菜菌核病菌菌株间对油菜的致病力存在明显分化,且致病力强弱与菌株的地理来源有关,宁国菌株致病力较弱,无为和桐城菌株致病力较强。采用DNS法测定了上述油菜菌核病菌菌株的纤维素酶活性,结果显示不同菌株的纤维素酶活值有较大差异,且酶活值大小与菌株的致病力强弱密切相关。进一步对菌株接种所致病斑长度(y)和纤维素酶活值(x)2个因子进行了相关分析,结果表明,供试菌株接种油菜48 h后所致病斑长度与相应菌株的纤维素酶酶活值呈极显著正相关(R2=0.8919),即供试的油菜菌核病菌菌株的致病力强弱与其纤维素酶活性高低成正相关。

The pathogenicity of 24 isolates of Sclerotiorum sclerotiorum, the cansal organism of rapeseed stem rot, obtained from Tongcheng, Wuwei, Ningguo, Jingde and Shouxian in Anhui was investigated by applying toothpick mycelium inoculation, respectively. The results showed that all of the tested isolates caused stem rot on rape, but there was significant difference in the average length of the lesions caused by different isolates, suggesting that there was significant differentiation in pathogenicity of S. sclerotiorum strains to rapeseed among isolates. The pathogenicity of the isolates was related to their localities. The pathogenicity of the isolates from Ningguo was weaker, while the pathogenicity of the isolates from Tongcheng and Wuwei was stronger. Then, the celluase activities of the isolates were tested with DNS method, and the results indicated that there was considerable difference in the celluase activities of the isolates, and the difference was nearly related to their pathogenicity. Farther, the correlativity of the pathogenicity and celluase activities of the isolates was analysed. It was suggested that the pathogenicity of the isolates and the celluase activities of S. sclerotiorum isohttes,were in positive correlativity （R^2 = 0. 8919）.