Two new Bacillus thuringiensis toxins active against Lepidoptera and Coleoptera

MIKEL DOMÍNGUEZ; IÑIGO RUIZ DE ESCUDERO; ISABEL MATAS; LEOPOLDO PALMA; DELIA MUÑOZ; PRIMITIVO CABALLERO

Mainz, Germany

Congreso; 47th ANNUAL MEETING of the SOCIETY FOR INVERTEBRATE PATHOLOGY and INTERNATIONAL CONGRESS ON INVERTEBRATE PATHOLOGY AND MICROBIAL CONTROL; 2014

Society for Invertebrate Pathology

The entomopathogenic spore-forming bacteria, Bacillusthuringiensis (Bt), is widely distributed around the world and isable to produce toxins with insecticidal activity during thevegetative and sporulation phase. The great genetic variety ofB. thuringiensis strains represents a huge diversity of potentialinsecticidal proteins. The host range of these proteins is highlyvariable, but includes a large number of species of the mostdamaging lepidopteran insect pests and also, other harmfulspecies of the orders Diptera, Coleoptera and Hymenoptera.In order to extend the number of Bt proteins active againstimportant coleopteran and lepidopteran pests, total DNA of astrain from a Spanish collection was completely sequenced.Two ORFs of 900 bp were selected due to their low identitywith other Bt proteins and were cloned in a Bt expressionplasmid. Proteins were produced and their insecticidal activitywas determined. Bm_47 protein was toxic againstLeptinotarsa decemlineata, with an LC50 of 54 μg/ml, whileBm_1711 protein was active against the lepidopteransHelicoverpa armigera and Ostrinia nubilalis, with an LC50 of164 and 34 ng/cm2, respectively. We discuss the importanceof this protein to combat species of coleopteran andlepidopteran pests, including species that have developedresistance to other Bt toxins.