一株感染家蚕的高致病性白僵菌的鉴定及在僵蚕生产中的应用

Identification of a Beauveria bassiana Strain with High Pathogenicity to Bombyx mori and Its Application in Bombyx Batryticatus Production

僵蚕是传统中药材,筛选对家蚕具有高致病性的球孢白僵菌用于提高规模化生产僵蚕的产量和品质。从蚕区采集的僵蚕虫体分离纯化到一株高致病力的白僵菌,通过形态学鉴定和rRNA ITS序列系统发育分析,确定该菌株为球孢白僵菌（Beauveria bassiana）,命名为Beauveria bassiana JC-1。优化该菌株应用于僵蚕生产中的接种菌液浓度为1×10^6～5×10^6mL^-1,用此浓度的菌液喷洒接种5龄起蚕后5～6 d,幼虫大量死亡,僵化率达90%以上,万头蚕可生产僵蚕约5 kg。利用该菌株感染家蚕收获所得僵蚕的各项质量指标均符合《中国药典》中的有关标准,且僵蚕的总灰分和酸不溶性灰分含量较市售僵蚕更低。初步认为该菌株在僵蚕的标准化、规模化生产中具有应用价值。

Bombyx batryticatus is a traditional Chinese medicine. Screening for Beauveria bassiana strains with high pathogenicity to silkworm（ Bombyx mori） would attribute to promotion of both output and quality of Bombyx batryticatus in large scale production. A Beauveria bassiana strain with high pathogenicity to silkworm was isolated from the naturally infected silkworm body. Based on morphological observation and rRNA ITS sequence phylogenetic analysis,this strain was identified as a species belonging to Beauveria bassiana and named as Beauveria bassiana JC-1. The optimized inoculation concentration of Beauveria bassiana JC-1 for Bombyx batryticatus production was 1 ×10^6to 5 ×10^6mL^-1. At 5 to 6 d after the spore suspension with this concentration was sprayed onto newly exuviated silkworm larvae of the 5th instar,the larvae died in large number,with petrification rate over 90%. The output of Bombyx batryticatus was about 5 kg per 10 000 silkworm larvae. All quality indexes of the acquired Bombyx batryticatus met the relevant standards in Chinese Pharmacopoeia. Moreover,total ashes content and acid-insoluble ash content were much lower in it than those in commercial Bombyx batryticatus. Therefore,this strain is considered to have application value in standardized and large scale production of Bombyx batryticatus.