For this Phase II research project, the Spodoptera active B.t. strain EG 2058 will be used as a model to delineate the role of P1 and P2 proteins in the production of overall insecticidal activity. Specific objectives include the indentification and characterization of a P1-type Spodoptera- active structural and regulatory toxin gene sequence in B.t. strain EG 2058 as well as a determination of the role of the P2 type gene in encoding the Spodoptera activity. Characterization of the Spodoptera-active P1 and P2 type gene expression will be performed by Western blot analysis of toxin proteins synthesized in B.t. strains constructed by microbial genetic or recombinant DNA technology. The effect of the presence of additional P1-encoding toxin plasmids on the expression of cloned Spodoptera-active genes, will be examined using similar Western blot analysis. Data obtained in this research will permit the assessment of regulatory interaction occurring between both similar and dissimilar genes at the gene-product level, and the effects of these interactions on the ultimate insecticidal activities of strain containing multiple genes. An understanding of these interactions will greatly facilitate the development of novel strains of B.t. having increased efficay against a variety of economically important target insects such as the army worm, Spodoptera exigna.
