Bacillus thuringiensis apr and npr genes, apr and npr B.t. strains, and method of use

摘要

The present invention is based on the discovery, isolation, sequencing and characterization of two protease genes present in Bacillus thuringiensis (B.t.). One is an alkaline protease gene generally designated "apr. " The other is a neutral protease gene generally designated "npr." The invention also includes genetically disabling the apr and the npr genes to reduce proteolytic activity of the proteases encoded by the genes, and using the disabled genes in insecticidal B.t. constructs along with one or more B.t. protein toxin genes. These resulting B.t. constructs are useful for the enhanced production of B.t. toxin protein. The B.t. toxin protein recovered from the fermentation production of these B.t. constructs also exhibits improved stability with respect to its insecticidal activity.