PAG-V: P345 - SUGARCANE TRANSFORMATION WITH A B.t. GENE FOR RESISTANCE TO THE LESSER CORNSTALK BORER (LCB)

Plant & Animal Genome V Conference

Town & Country Hotel, San Diego, CA, January 12-16, 1997.

P345

SUGARCANE TRANSFORMATION WITH A B.t. GENE FOR RESISTANCE TO THE LESSER CORNSTALK BORER (LCB)

FITCH, MAUREEN(1), V. Chang(2), F. Perlak(3), A. Dela Cruz(3), A. Ota(3), P. Moore(3)
1. U.S. Department of Agriculture, 99-193 Aiea Hts. Dr., Aiea, HI 96701
2. Hawaii Agriculture Research Center, 99-193 Aiea Hts. Dr., Aiea, HI 96701
3. Monsanto Company, 700 Chesterfield Village Parkway, St. Louis, MO 63198

Germinating sugarcane can be heavily damaged by larvae of the moth Elasmopalpus lignosellus (Zeller), the lesser cornstalk borer (LCB). Transgenic sugarcane was produced by particle bombardment of commercial sugarcane cultivars, H62-4671, H73-6110, and H78-4153, with a DNA construct containing a gene encoding the Bacillus thuringiensis (bt) protein CryIa(c) HD-73. The construct pMON19344 contains both the neomycin phosphotransferase II (NPTII) gene, for selection of transformed cells, and a modified Bt gene, for insect resistance. Transgenic calli and regenerated plants were screened for effectiveness on LCB larva growth inhibition. Out of 26 callus lines screened in 18 replicates, larval mortality was high (90-100%) for 38%, moderate (50-90%) for 38%, and low (0-50%) for 23% of the calli. Mortality was lower when larvae fed on plants. Twenty seven plant lines screened showed very high mortality (80-100%) on 15%, moderate mortality (50-80%) on 52%, and low mortality (0-50%) on 33% of the plant lines. Plants may produce reduced levels of the toxic protein. Southern hybridizations of three of the most LCB resistant lines showed bands of the same molecular weight as the plasmid Bt fragment. There are approximately 1-5 copies of the Bt gene in each transgenic line. All lines also showed strong NPTII expression. Field testing in heavily infested LCB locations will show if the resistance observed in the labortaory will be useful in commercial plantings.