高毒力金龟子绿僵菌的筛选及其胞外蛋白酶产量测定

Screening for high virulence strains of Metarhizium anisopliae and yield determination of its extracellular protease

以大蜡螟Galleria mellonella L.幼虫为供试昆虫,对从果园土壤中筛选出的金龟子绿僵菌Metarhizium anisopliae的生物活性进行了测定,共获得4株高毒力菌株,其LT50值在1.85～2.56 d之间,LD50值在6.11×102～1.55×104spores之间。利用明胶-琼脂平板分析法对筛选出的高毒力绿僵菌菌株产胞外蛋白酶的水平进行了测定,结果显示,各菌株间产酶水平差异较大,且菌株产酶水平的高低与其对大蜡螟幼虫的毒力之间存在明显的线性相关性。

The virulence of different Metarhizium anisopliae,which screened from orchards soil,was evaluated by using the larvae of Galleria mellonella L.as the test insect in laboratory.Four high virulence strains of M.anisopliae were obtained,the LT50 values were between 1.85 d and 2.56 d.The LD50 values were between 6.11×10^2 and 1.55×10^4 spores.Gelatin-AGAR analysis method was used to determine the extracellular protease enzyme levels of the high virulence strains of M.anisopliae.The results showed that the production of extracellular protease among high virulence strains was different,and there was an obvious liner correlation between extracellular protease level and pathogenicity to larvae of G.mellonella.