Engineering Transgenic Eggplant (Solanum melongena L.) Resistant to the Colorado Potato Beetle (Leptinotarsa decemlineata Say)

A chimeric construct, containing the synthetic cryIIIA (Btt) gene, the NPTII selectable marker and the uidA reporter gene, was incorporated via Agrobacterium tumefaciens into eggplant, variety Hibush. The synthetic cryIIIA gene, altered at the nucleotide level without changing the amino acids of the toxic protein by J. Kemp of New Mexico State Univ., Las Cruces, is adapted for high expression in plant cells. To verify the transgenic status, GUS assays were performed on over 300 plants, from which 185 were confirmed to be transgenic. Physical incorporation of the chimeric construct was further confirmed by Southern analysis of about 30 transgenic plants; both single and multiple site incorporation of the Btt gene were found. Resistance to Colorado potato beetle (CPB) was assessed by: a) placing egg masses of CPB on leaves of plants grown in the growth chamber; b) placing first-instar larvae on detached leaves; c) observing 173 transgenic plants under field conditions. About 60% of the transgenic plants displayed a very high level of resistance to CPB. No larvae survived on the resistant plants longer than 50–60 hours after hatching. Upon selfing, the transgenic plants with a single construct segregate in the S 1 generation in a Mendelian fashion.