Cloning, expression and characterisation of a promising mosquitocidal gene

A new mosquitocidal gene, cyt1Aa6, was isolated and cloned from the novel Bacillus thuringiensis strain LLP29, previously isolated from the phylloplane of Magnolia denudata. Nucleotide sequence analysis of cyt1Aa6 indicated that the open reading frame consisted of 750 base pairs, encoding 249 amino acid sequences with a calculated molecular weight of 27.3681 kDa and a PI value of 4.77. An homological comparison revealed that the cyt1Aa6 amino acid sequence was 99% identical with those of known Cyt1Aa proteins. In addition, the cyt1Aa6 gene was successfully expressed in Escherichia coli BL21. Bioassays on Aedes albopictus showed that Bt LLP29 and the expressed BL21 were both toxic to 3rd-instar mosquito larvae. The isolation of cyt1Aa6 provides new opportunities for selecting new strains and to obtain novel B. thuringiensis products based on its toxins.