Characterisation and expression of a novel haplotype cry2A-type gene from Bacillus thuringiensis strain JF19-2

The Bacillus thuringiensis isolate JF19-2, a native organism found in soil samples from the Sichuan Basin in western China, contains a bipyramidal crystal harbouring one insecticidal crystal protein (about 70 kDa). Interestingly, a novel cry2A-type gene, encoding a 635 amino acid protein with 92% homology to cry2Ab1, was found and cloned from this strain. According to the nomenclature principles adopted for B. thuringiensis insecticidal crystal proteins, this gene represents a novel haplotype cry gene and was designated as cry2Ag1 by the Bacillus thuringiensis Pesticide Crystal Protein Nomenclature Committee. Cry2Ag1 was expressed in Escherichia coli BL21(DE3)pLysS cells, and the results of insecticidal activity assays showed that Cry2Ag1 was toxic to both Dipteran (Aedes aegypti) and Lepidopteran (Plutella xylostella and Helicoverpa armigera) pests. These results strongly suggest that the cloning of the cry2Ag1 gene is not only of interest to researchers studying insecticidal crystal genes, but may ultimately serve as a solution to the increasing resistance of pests to currently used insecticides.