Transgenic cotton containing synthetic ω-ACTX-HV 1a gene confers broadspectrum protection against major bollworms and leaf army worms

Abstract Incorporation and stable expression of different Bt and non-Bt genes in cotton have demonstrated an effective control of different insect pests of cotton crop. In present study, a synthetic insecticidal transgene encoding ω-ACTX-HV1a toxin (Hvt) of an Australian funnel web spider ( Hadronyche versuta ), when transformed into cotton (Coker-312) through A. tumefaciens method, showed insecticidal activity against three major cotton pests i.e. American bollworm (Helicoverpa armigera) , spotted bollworm (Earias vittella) and leaf army worm (Spdotera littoralis) . Fertile transgenic cotton (T0 generation) plants were developed through tissue culture process from six selected independent transgenic events and established successfully in the soil. Putatively transgenic T 0 cotton plants were analyzed by PCR and Southern hybridization confirming transgene presence and integration in 1–3 copies. Northern blots revealed a high Hvt expression among transgenic lines. Under in-vitro conditions, entomocidal assays showed high level of 1-2nd instar in both major H. armigera and S. littoralis reaching 80–100% mortality after 72–96 hrs of their release on detached leaves. Similarly, transgenic hvt cotton plants showed exclusive protection upto 90% against infestation of spotted bollworm under in-vivo conditions in containment. Insecticidal activity was observed in T 0 regenerated cotton plants but also inherited in subsequent generations. Development of Hvt cotton may have significant commercial contribution for sustainable insect pest management and it can be used in combination or as fusion with other (Bt/non-Bt) transgenes to circumvent resistance development in cotton insect pests. To our knowledge, this is first transgenic cotton expressing nerve toxin that possess significant mortality against spotted bollworm ( Earias vittella) and it will give innovational supplement to already insect resistant bt cotton.