Cloning, expression and characterisation of a promising mosquitocidal gene

Abstract

A new mosquitocidal gene, <i style="">cyt1Aa6</i>, was isolated and cloned from the novel<i style=""> Bacillus thuringiensis</i> strain LLP29, previously isolated from the phylloplane of <i style="">Magnolia denudata</i>. Nucleotide sequence analysis of c<i style="">yt1Aa6</i> 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 <i style="">cyt1Aa6</i> amino acid sequence was 99% identical with those of known Cyt1Aa proteins. In addition, the <i style="">cyt</i>1Aa6 gene was successfully expressed in <i style="">Escherichia coli </i>BL21. Bioassays on<i style=""> Aedes albopictus</i> showed that Bt LLP29 and the expressed BL21 were both toxic to 3rd-instar mosquito larvae. The isolation of <i style="">cyt1Aa6</i> provides new opportunities for selecting new strains and to obtain novel<i style=""> B. thuringiensis</i> products<i style=""> </i>based on its<i style=""> </i>toxins.