Development of insect-resistant cotton through expression of Cry2Ab protein

Abstract:

What if cotton could defend itself against bollworm without a single spray? This research developed transgenic cotton lines expressing the Bacillus thuringiensis Cry2Ab protein and evaluated their insecticidal efficacy under contained glasshouse and field conditions at Cirencester, United Kingdom, during 2021-2023. Four independent transformation events were generated via Agrobacterium-mediated transfer into cultivar ‘Coker-312’. Leaf bioassays with neonate Helicoverpa armigera showed larval mortality ranging from 82.4% (event Cry2Ab-4) to 94.3% (event Cry2Ab-1), compared with 12.8% on non-Bt controls. Cry2Ab protein concentration in young leaves ranged from 2.2 to 3.8 µg g^-1 fresh weight. Under field cage conditions, boll damage was 4.2% on Cry2Ab-1 versus 48.6% on the non-Bt isoline. Seed cotton yield of the best event reached 2,840 kg ha^-1, 69% above the non-Bt check. Southern blot confirmed single-copy integration in Cry2Ab-1 and Cry2Ab-3. These lines represent promising material for introgression into commercial upland cotton backgrounds.