IMPROVED INSECTICIDAL BACTERIA, AND METHODS FOR MAKING AND USING THEM

The invention relates to nucleic acid sequences comprising a BtI or BtII promoter, or a combination of a BtI and a BtII promoter, at least 6 contiguous nucleotides of a bacterial STAB-SD sequence, and a sequence encoding a polypeptide with at least 80% sequence identity to a 41.9 kD protein of the B. sphaericus (Bs) binary toxin, which polypeptide has at least 50% of the toxicity of the native 41.9 kD protein. Optionally, the sequence further encodes a second polypeptide with at least 80% sequence identity to the 51.4 kD protein of the Bs binary toxin and which can function as a binding domain for the Bs 41.9 kD toxin protein. When the nucleic acid sequences are expressed in B. thuringiensis (Bt) or Bs cells, they result in at least 10 times the production of Bs binary toxin compared to untransformed Bs cells. The invention provides nucleic acid sequences, expression vectors, host cells, and methods of increasing the toxicity of an insecticidal bacterium by transforming the bacterium with nucleic acid sequences of the invention. Further, the invention relates to the discovery that the Cyt1Aa1 protein of Bt subspecies israelensis (Bti) reverses resistance to Bs binary toxin in larvae of Bs-resistant mosquitoes. The invention provides Bs cells expressing Bti Cyt1Aa1 protein, and methods of reducing resistance to Bs binary toxin by co-administering the Cyt1Aa1 protein with Bs binary toxin. La invencion se refiere a secuencias de acidos nucleicos que comprenden un promotor BtI o BtII o una combinacion de un promotor BtI y un BtII, al menos 6 nucleotidos contiguos de una secuencia STAB-SD bacterial y una secuencia que codifica un polipeptido con al menos 80% de identidad de secuencia para una proteina de 41.9 kD de la toxina binaria de B. sphaericus ("Bs") cuyo polipeptido tiene al menos 50% de la toxicidad de la proteina de 41.9 kD nativa. Opcionalmente, la secuencia ademas codifica un segundo polipeptido con al menos 80% de identidad de secuencia para la proteina de 51.4 kD de la toxina binaria Bs y que puede funcionar como un dominio de union para la proteina de toxina Bs de 41.9 kD. Cuando las secuencias de acido nucleico se expresan en celulas de B. thuringiensis ("Bt") o Bs dan como resultado al menos 10 veces la produccion de la toxina binaria Bs comparadas con las celulas Bs no transformadas. La invencion proporciona secuencias de acido nucleico, vectores de expresion, celulas huesped y metodos para incrementar la toxicidad de una bacteria insecticida a