一株病原真菌的分离鉴定及对淡色库蚊幼虫的致病性测定

Screening and identification of an isolate and its pathogenicity to Culex pipiens pallens

目的筛选对淡色库蚊幼虫具有高致病力的资源菌株。方法从土壤中分离获得对淡色库蚊幼虫有致病力的资源菌株,进行形态学和分子生物学鉴定,并检测其对淡色库蚊幼虫的最佳致病温度。结果经鉴定新分离的菌株为淡色生赤壳菌,在实验室条件下该菌株对淡色库蚊幼虫有高致病力,用浓度为1.0×106个/mL的孢子悬浮液处理淡色库蚊3龄幼虫,10 d累计死亡率为100%。该菌株对淡色库蚊幼虫的最佳致病温度范围为24℃~26℃,LT50低于3 d。不同温度条件下,淡色生赤壳菌对淡色库蚊的致病力差异显著(F=27.569,df=23,P<0.05)。结论分离的淡色生赤壳菌对淡色库蚊幼虫具有高致病力,可作为媒介蚊虫生物防制的资源菌株进一步研究。

Objective To screen for strains that are highly pathogenic to Culex pipiens pallens larvae.Methods Strains were isolated from the soil.The most pathogenic biocontrol strain and its concentration of spores were identified based on a pathogenicity test.The strain was identified morphologically and molecularly.Results According to its morphological characteristics and 18 S rDNA sequencing,the strain was identified as Bionectria ochroleuca.At a spore concentration of 10~6/mL,the mortality rate of Cx.pipiens pallens larvae was 100%after ten days of treatment.The optimum pathogenic temperature range for Cx.pipiens pallens was 24-26℃.At different temperatures for 10 d,the pathogenicity of the strains to Cx.pipiens pallens differed significantly(F=27.569,df=23,P<0.05).Conclusion Results indicated that the strain B.ochroleuca was highly virulent to Cx.pipiens pallens and that it could be used as a biocontrol fungus for further research.