Transgenic crops for insect resistance

Pest insects cause significant yield losses to agricultural crops each year. To deal with such a detrimental impact, farmers rely primarily on applications of insecticides. Unfortunately chemical control may have negative effects on the environment. In addition, the efficacy of insecticides is often affected by weather and cultural conditions. The recent remarkable progresses in insecticidal toxin genes and crop transformation methods have made intrinsic insecticidal crops available to farmers as an alternative to fight insect pests more effectively and economically. Many insecticidal protein toxins have been identified and molecularly characterized. Some were tested for in planta expression in crop plants. Only transgenic crops with Cry genes isolated from Bacillus thuringiensis (Bt) have been commercialized to date. These transgenic crops target Lepidopteran and Coleopteran insects. Cry proteins are highly efficacious against certain target insect species, and Cry genes are usually straightforward for transformation and gene expression in crop plants. Thus far, the predominant commercialized transgenic crops with insect resistance traits are still limited to corn and cotton. Those transgenic crops are cultivated on several million hectares around the world, mostly in North America. Insecticidal genes and the generation of transgenic crops for insect resistance are reviewed and discussed.