TRANSGENIC EXPRESSION OF TRANSLATIONAL FUSION OF SYNTHETIC Cry1Ac AND Hvt GENES IN TOBACCO CONFERS RESISTANCE TO Helicoverpa armigera AND Spodotera littoralis LARVAE

摘要

Single toxin in crops to defend them from herbivorous insects has proven an effective mean of reducing farmer's dependence on environmentally unsafe chemical insecticides. On the other hand insects have great natural ability to develop resistance against these toxins. The incorporation of multiple genes in a plant that produces proteins with different insecticidal mechanisms has the potential to delay insect resistance more effectively than a single gene, or two or more genes that produce proteins with similar mechanism. In the present investigation the translational fusion of two unrelated genes i.e. omega atracotoxin (Hvt) and Cry1Ac derived from an Australian spider (Hadronyche versuta) and Bacillus thuringiensis, respectively was transformed and characterized in Nicotiana tabacum L. cv. spade. Transgene expression level was confirmed to transcriptional level by reverse transcriptase PCR (RT-PCR) and to protein level by western blotting and immunological detection. Leaf bioassays demonstrate the effectiveness of this translational fusion with 100% mortality in Spodoptera littoralis and Helicoverpa armigera larvae within 48 and 72 h, respectively. The present study shows that new chimeric protein with two different insecticidal mechanisms retained its biological activity in plant system against agronomically important insects and is an exceptional candidate for long lasting transgenic protection of crop plants.