Characterization and Cloning of cry Genes from a Novel Serogroup Mosquitocidal Strain, Bacillus thuringiensis Serovar mogi

다국어 초록 (Multilingual Abstract)

Plasmids from Bacillus thuringiensis have been implicated in pathogenicity as they carry the genes responsible for different types of diseases that in mammals and insects. A novel serogroup (H3a3b3d), B. thuringiensis strain K4 which showed mosquitocidal activity against Anopheles sinensis and Culex pipiens pallens, was isolated from fallen leaves in Mungyeong city, Republic of Korea. In contrast to the complicated plasmid profiles of B. thuringiensis H3 serotype strains, the strain K4 (designated as serovar mogi) had only one large plasmid (>200kb) on which the toxin genes were occasionally located. A 454 pyrosequencing was used for the complete sequencing of the large plasmid. The sequence analysis showed that k4 plasmid had at least seven putative cry genes, ending up to showing 84%, 75%, 73%, 58%, 84%, 39% and 75% homology with Cry27Aa, Cry19Ba, Cry20-like, Cry56Aa, Cry39ORF2, Cry8Ba and Cry40ORF2 toxins in amino acids, respectively. This novel 3a3b3d type strain, B. thuringiensis serovar mogi, can be used as a good resource for studying unknown mosquitocidal cry genes. The E. coli-B. thuringiensis shuttle vector, pHT1K was used to clone these cry genes for characterization. In each clone, the level of transcription and production of crystal proteins will be investigated in near the future.