USE OF BACILLUS-THURINGIENSIS GENES IN TRANSGENIC COTTON TO CONTROL LEPIDOPTEROUS INSECTS

Transgenic cotton, Gossypium hirsutum L., plants containing modified, truncated versions of the cryIA genes from Bacillus thuringiensis var kurstaki are resistant to many Lepidopterous insects. Plants containing specific, truncated versions of the crvIA gene were resistant to tobacco budworm, Heliothis virescens Fab., in field and laboratory studies in my laboratory. Other researchers have shown that these transgenic plants are also resistant to bollworm, Helicoverpa zea (Boddie); pink bollworm, Pectinophera gossypiella (Saunders); cotton leafperforator, Bucculatrix thurberiella Busck; and saltmarsh caterpillar, Estigmene acrea (Drury). Others have shown that the proteins coded for by the B. thuringiensis genes bind selectively to sites in the brush borders of epithelial cells in the midgut of the insect and induce the formation of small pores (0.5 to 1.0 nm) in the cell membranes, resulting in a net influx of ions and outflow of water. The cells swell and lyse. The B. thuringiensis genes in transgenic cotton plants Appear to offer an environmentally desirable control method for Lepidopterous cotton pests when used in integrated pest management programs.