Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 1999
Publication Date: N/A
Technical Abstract: Expression of insecticidal agents in transgenic crop plants is selectively toxic to herbivorous pests but benign to beneficial insects. However, the near exclusive use of Bacillus thuringiensis endotoxin (Bt) genes in transformed plants places enormous selective pressure on the pest population towards development of resistance to Bt. Identification of new insecticidal agents and successful delivery of these compounds into insect pests is, therefore, critical. For efficacy, these agents must survive the harshly proteolytic and alkaline environment of the insect midgut. Nucleopolyhedrosis virus (NPV) infects insects by ingestion and uptake of virions through the peritrophic membrane and attachment to midgut cells. The protein, p74, which resides on the NPV envelope, is a participant in the initial interaction with the host midgut cell. We will determine whether p74 alone can be used to vector proteins into midgut cells. Fusion of p74 to the green fluorescent protein (GFP) will allow in situ monitoring of the fate of this recombinant protein as it travels from transgenic leaf (insect diet) into insect midgut cells. If p74/GFP fusions are taken up, dissection of larvae will allow further tracking of the recombinant protein. Fusions of truncated forms of p74 to GFP may further delineate the portion of the protein that interacts with the host cell. Cloning of the p74/GFP fusions into a tobacco mosaic virus (TMV) vector, followed by infection of leaves with the recombinant TMV, will allow expeditious high level expression of p74/GFP fusions in plants. This strategy for rapid expression and delivery of insecticidal proteins should augment evaluation of novel entomocidal toxins in transgenic plants.