CLONING AND EXPRESSION OF A NOVEL TOXIN GENE FROM BACILLUS-THURINGIENSIS SUBSP JEGATHESAN ENCODING A HIGHLY MOSQUITOCIDAL PROTEIN

A gene, designated cry11B, encoding a 81,293-Da crystal protein of Bac illus thuringiensis subsp.jegathesan was cloned by using a gene-specif ic oligonucleotide probe. The sequence of the Cry11B protein, as deduc ed from the sequence of the cry11B gene, contains large regions of sim ilarity with the Cry11A toxin (previously CryIVD) from B. thuringiensi s subsp. israelensis. The Cry11B protein was immunologically related t o both Cry11A and Cry4A proteins. The cry11B gene was expressed in a n ontoxic strain of B. thuringiensis, in which Cry11B was produced in la rge amounts during sporulation and accumulated as inclusions. Purified Cry11B inclusions were highly toxic for mosquito larvae of the specie s Aedes aegypti, Culex pipiens, and Anopheles stephensi. The activity of Cry11B toxin was higher than that of Cry11A and similar to that of the native crystals from B. thuringiensis subsp.jegathesan, which cont ain at least seven polypeptides.