Cry1Ab

CS-Cry1Ab

Cry1Ab delta-endotoxin

The cry1Ab gene codes for a delta-endotoxin, commonly known as "Bt-toxin", which confers resistance to the plant to lepidoptera larvae such as the European corn borer (Ostrinia nubilalis), the southwestern corn borer (Diatraea grandiosella), pink borer (Sesamia cretica), Spruce Budworm, Tent caterpillar, Gypsy moth, Diamondback moth, Cabbage looper, Tobacco budworm, and Cabbage worm.

Cry proteins, of which Cry1Ab is only one, act by selectively binding to specific sites localized on the lining of the midgut of susceptible insect species. Following binding, pores are formed that disrupt midgut ion flow, causing gut paralysis and eventual death due to bacterial sepsis. Cry1Ab is lethal only when eaten by the larvae of lepidopteran insects (moths and butterflies), and its specificity of action is directly attributable to the presence of specific binding sites in the target insects.