A combination of cry (Cry2Ab) and plant lectin (PTA) genes confers resistance against major sucking and chewing insect pests of cotton

Background: Insect pests constitute a considerable risk to global crop production. Although Bacillus thuringiensis (Bt) toxins produced in transgenic plants are effective against chewing insect pests, they do not protect plants against sucking insect pests, and continued use of Bt crops in the field can lead to the evolution of resistant pest species. However, several plant-derived mannose binding lectins are effective against sucking insect pests. Methods and results: To provide broad-spectrum and durable resistance against multiple insect pests, we produced a double gene construct harboring Cry2Ab (encoding a B. thuringiensis toxin) and PTA (Pinellia ternata leaf agglutinin, encoding a plant lectin). Nicotiana benthamiana and Arabidopsis thaliana were used as model plant systems for characterizing the double gene construct (Cry2Ab + PTA). Transgenic plants were made and evaluated to measure the efficacy of Cry2Ab + PTA against chewing and sucking insect pests. Molecular investigation of transgenic A. thaliana plants showed stable integration and expression of the Cry2Ab and PTA genes. On N. benthamiana expressing Cry2Ab + PTA, Myzus persicae (green peach aphid) mortality was 74%, compared to 25% on non-transgenic controls. Bemisia tabaci (whitefly) mortality was 78%, compared to 22% on non-transgenic controls. Spodoptera frugiperda (fall armyworm) showed 83% mortality when fed on transgenic A. thaliana plants expressing Cry2Ab + PTA, whereas 17% mortality was observed on non-transgenic control plants. Conclusion: The Cry2Ab + PTA construct protects plants against both sucking and chewing insects, suggesting that this construct can be introduced into cotton and other crops to control multiple insect pests.