水稻纹枯病菌胞外蛋白酶分离纯化及部分特性分析

Purification of An Extracellular Protease Produced by Rhizoctonia solani and Its Partial Characterization

[目的]为深入研究水稻纹枯病菌的致病机理奠定基础。[方法]水稻纹枯病菌(Rhizoctonia solaniKhn)发酵液经硫酸铵沉淀,用离子交换柱层析、疏水层析和分子筛层析方法分离纯化胞外蛋白酶。[结果]从水稻纹枯病菌发酵液中分离纯化到一个分子量约为49.5ku的胞外蛋白酶。其活性最适温度为30℃,最适pH为6.4。Zn2+、Fe3+、Cu2+对酶活性有抑制作用,Mg2+、Mn2+对酶活性无影响,Ca2+在低浓度下对酶活性有激活作用。[结论]水稻纹枯病菌可产生胞外蛋白酶,该胞外蛋白酶与水稻纹枯病菌致病性的关系还有待深入研究。

[Objective]The aim of the study was to provide the basis for researching the pathogenicity mechanism of Rhizoctonia solani.[Method]The extracellular protease was purified after ammonium sulfate precipitation,DEAE-Sephrase Fast Flow,Phenyl-Sepharose Fast Flow and Sephadex G-75 ch rom atography.[Result]The protease has a molecular mass of 49.5 ku based on SDS-PAGE.The optimal temperature and pH value for it activity were 6.4 and 30 ℃ respectively.Zn^2＋、Fe^3＋、Cu^2＋ can inhibit enzymatic activity,but Mg^2＋、Mn^2＋ can not,and Ca^2＋ can activate enzymatic activity in low concentration.[Conclusion]R.solani can secrete extracellular protease,but the role in the pathogenicity of R.solani to rice was unknown.