Genes from Bacillus thuringiensis entomocidus 60.5 coding for insect-specific crystal proteins

Summary Five crystal protein genes have been isolated from DNA of Bacillus thuringiensis entomocidus 60.5, an isolate selected for its high toxicity against Spodoptera littoralis and Spodoptera exigua. Two of these genes belong to a family of well-described crystal protein genes. The toxic properties of the corresponding proteins are similar to those of isolate kurstaki HD1. The other three genes belong to gene families not described before. One of these genes codes for a protein product exhibiting a high degree of specificity towards Spodoptera species, explaining the high toxicity of isolate entomocidus 60.5 against these species. This gene product is much less toxic against larvae of Heliothis virescens and Pieris brassicae. Its coding sequence is separated from a supposed fourth crystal protein gene by a stretch of DNA of 3 kb. The crystal protein encoded by the fifth gene is mainly active against P. brassicae. Homology between the crystal protein genes is limited to the central region of the coding sequences, including the proteolytic cleavage site, except for the first two genes between which homology is extensive.