Identification of Cyt2Ba from a New Strain of Bacillus thuringiensis and Its Toxicity in Bradysia difformis

• Published in: Current microbiology Vol. 77; no. 10; pp. 2859 - 2866
• Main Authors: Wang, Fan-Fan, Qu, Shao-Xuan, Lin, Jin-Sheng, Li, Hui-Ping, Hou, Li-Juan, Jiang, Ning, Luo, Xin, Ma, Lin
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2020; Springer Nature B.V
• Subjects: Affinity chromatography; Animals; Bacillus thuringiensis; Bacillus thuringiensis - classification; Bacillus thuringiensis - genetics; Bacillus thuringiensis Toxins - toxicity; Biological control; Biomedical and Life Sciences; Biotechnology; Bradysia difformis; China; Diptera - drug effects; E coli; Endotoxins - toxicity; Escherichia coli - genetics; Fusion protein; Hemolysin Proteins - toxicity; Larva; Larvae; Life Sciences; Microbiology; Mushrooms; Mycelia; Pest Control, Biological; Pests; Phylogeny; Pleurotus geesteranus; Pleurotus ostreatus; Proteins; Recombinant Proteins - toxicity; RNA, Ribosomal, 16S - genetics; rRNA 16S; Toxicity; Toxins; China
• ISSN: 0343-8651; 1432-0991
• DOI: 10.1007/s00284-020-02018-y

Bradysia difformis is one of the most damaging pests in mushroom production in China. In this study, eight Bacillus thuringiensis strains were analyzed for insecticidal activity in B. difformis . The strain JW-1 showed the highest insecticidal activity against B. difformis larvae, but did not inhibit the mycelial growth of Pleurotus ostreatus and P. geesteranus . The 16S rRNA gene (1397 bp) and cyt2 gene (792 bp) were obtained from strain JW-1. The phylogenetic tree based on 16S rRNA gene and Cyt2 toxin showed that strain JW-1 was a member of B. thuringiensis and Cyt2 toxin belonged to Cyt2Ba toxin cluster. The Cyt2Ba toxin from strain JW-1 was overexpressed in E. coli as a fusion protein and the fusion protein (70 kDa) was purified by Ni-IDA affinity chromatography. The purified Cyt2Ba fusion protein was toxic to B. difformis larvae (LC 50 was 2.25 ng/mL). The identification of Cyt2Ba from strain JW-1 and confirmation of the insecticidal activity of Cyt2Ba in B. difformis provided a new means of biological control of the important pest in mushroom production.