根虫瘟霉转寄主过程中毒力相关胞外蛋白酶系的诱导表达  

THE EXPRESSION OF EXTRACELLULAR PROTEASE ASSOCIATED WITH ZOOPHTHORA RADICANS VIRULENCE INDUCED BY PLUTELLA XYLOSTELLA

作　　者：盛亮[1] 徐均焕[1] 

机构地区：[1]浙江大学微生物研究所,杭州310029

出　　处：《菌物学报》2004年第2期226-232,共7页Mycosystema

基　　金：国家自然科学基金 (30070025);浙江省自然科学基金 (302016);国家科技部(G2000016208-04)

摘　　要：根虫瘟霉Zoophthora radicans是寄主范围较广的专性昆虫病原真菌.在该菌胞外蛋白酶系与毒力变化关系的研究中,不同寄主来源的根虫瘟霉菌株产胞外蛋白酶水平与其对小菜蛾(Plutella xylostella)的毒力间无明显的相关性.但转寄主各代菌株随毒力逐步上升产胞外蛋白酶水平也有所增加,两者间有一定的相关性.经活性电泳检测显示,ARSEF1342原始菌株(R0)有分子量分别为148kD,153kD和162kD的三条蛋白酶条带,但转寄主传代菌株(R1～R4)的148kD蛋白酶条带突然消失,而153kD蛋白酶条带则随转寄主传代数增加逐步趋于明显,相关性分析发现153kD和148kD与毒力间具有较好的相关性.这表明根虫瘟霉菌株在转寄主过程中逐渐增加了对新寄主具有较高基质特异性的胞外蛋白酶的诱导表达,从而使转寄丰菌株更适应对新寄主的入侵及致病.Zoophthora radicans is a specific insect-pathogenic fungus with a broad host range. The relationship between virulence and extracellular proteases has been studied. It was indicated that there was no correlation between extracellular protease activities of various Z. radicans isolates and their virulence against Plutella xylostella, while Z. radicans reisolates from P. xylostella resulted in a gradual increase inextracellular protease production as well as virulence against P. xylostella,and there were correlated to each other in a certain extent. Electrophoresis detection showed that ARSEF1342, the original strain (R0produced three protease bands corresponding to molecular masses of 148kD, 153kD and 162kD respectively,whereas the band of 148kD was abruptly lost in the Z. radicans reisolates (R1~R4) , but the 153kD band gradually became obvious along with passages of reisolates. Comparably reliable correlation betweenvirulence against P. xylostella and the relative concentration of 153kD or 148kD band was found byregression analysis. This indicated that induced expression of high substrate-specific extracellular protease was enhanced during passages of reisolate from P. xylostella, which will consequently facilitate reisolates foR NON-ORIGINAL HOST INFECTION AND DISEASE FORMATION.

关 键 词：昆虫病原真菌 连续传代 非原始寄主 小菜蛾 胞外蛋白酶 表达 

分 类 号：Q939.5[生物学—微生物学]