白粉菌侵染中国月季对甜菜夜蛾幼虫乙酰胆碱酯酶活性的影响

摘要

采用光度法研究中国月季感染白粉菌对甜菜夜蛾幼虫体内蛋白质含量和乙酰胆碱酯酶( AChE)活性的影响,为寄主植物介导的间接的病虫互作机制研究提供依据。结果表明,中国月季感染月季白粉菌后对取食中国月季的甜菜夜蛾产生了不利影响,使幼虫蛋白质含量和乙酰胆碱酯酶活性降低。取食感病中国月季叶片9d后,与取食健康叶片相比,幼虫体内蛋白质含量下降了81.77%(P<0.01),同时,AChE 比活力为8.89μmol/(mg·min),下降了68.03%(P <0.01)。AChE的米氏常数(Km)和最大反应速率(vmax)也受到明显影响,Km增大(P<0.001)、vmax减小(P<0.001),均表明AChE活性降低。从昆虫生理学角度证明,白粉菌侵染中国月季对甜菜夜蛾造成的抑制作用与幼虫体内蛋白质含量变化和AChE活性变化有关。%With spectrometry method,the changes of protein content and acetylcholinesterase( AChE) ac-tivity in the larvae of beet armyworm,Spodoptara exigua(Hübner),fed on rose leaves infected with rose powdery mildew,Sphaerotheca pannosa( Wallr.:Ex Fr. ) Lév. ,were determined in the present study,to provide reference for understanding the mechanism of plant-mediated indirect interaction between phyto-pathogenic fungi and insects. The beet armyworm was detrimentally influenced by infection of its host plants of rose,Rosa chinensis Jacq. Therefore,the protein content and the AChE activity of the larvae fed on mildew-infected rose leaves decreased. After the larvae were fed on infected rose leaves for nine days, the protein content decreased by 81. 77%(P<0. 01) and the AChE activity[8. 89 μmol/(mg·min)] decreased by 68. 03%(P<0. 01),when compared with larvae fed on healthy rose leaves. Also the Km ( Michaelis-Menten constant) and vmax ( maximum velocity of hydrolysis) of AChE were detrimentally af-fected[Km increased(P<0. 001) and vmax decreased(P<0. 001)],showing that the AChE activity de-creased when the larvae were fed with mildew-infected rose leaves. The obtained results from the aspect of insect physiology demonstrate that the inhibition of infection of rose plants by powdery mildew on beet ar-myworm is clearly related to the changes of protein content and activity of AChE in the larvae of beet ar-myworm.