Submitted to: Dekker Encyclopedia of Plant and Crop Science
Publication Type: Book / Chapter
Publication Acceptance Date: June 17, 2003
Publication Date: May 1, 2004
Citation: Jenkins, J.N. 2004. Genetically engineered crops with resistance to insects. In: Encyclopedia of Plant and Crop Science. New York, NY: Marcel Dekker. p. 506-508. Interpretive Summary: Insecticides are a major cost in production of most crop plants. Where available, resistant plants control these pests in an effective manner. Lack of effective genes for insect resistance within the crop species has limited plant breeders in the development of resistant varieties for many major crops. Genetic transformation technology allows genes to be moved across species, which greatly improves the opportunities for plant breeders to produce plants that are resistant to attack by insects. Cotton, corn, and potato plants have been genetically transformed so that they express a toxin from a common soil bacterium, Bacillus thuringiensis. These plants are called transgenic plants. Transgenic cotton, with a modified gene from B. thuringiensis, controls tobacco budworm, bollworm, and pink bolloworm. Transgenic corn, with a modified gene from B. thuringiensis, controls several major pests of corn. Transgenic potato, with a modified gene from B. thuringiensis, controls Colorado potato beetle. Many benefits accrue from use of these transgenic plants. Profits generally increase, fewer insecticides are applied, beneficial insects are preserved, and there are improvements for wildlife in the area. Over 240 proteins that control insects have been classified from B. thuringiensis, thus a large supply of toxins appears to be available. In addition, proteins that act as insect toxins are produced by the vegetative growth phase of B. thuringiensis and B. cerus. Plant amylase inhibitors, plant lectins, chitinases, and animal serine protease inhibitors are also being investigated for insect control in transgenic plants. In the year 2000, there was 3.2 million ha of transgenic cotton grown with most of this in the USA. China, Australia, Mexico, and South Africa also grew transgenic cotton in 2000. In 2000 there was 6.8 million ha of transgenic corn grown with 92% of this in the USA.
Technical Abstract: Genetic transformation technology allows genes to be moved across species, greatly improving the opportunities to breed plants for insect control. The Cry1Ac protein in cotton, Gossypium hirsutum L., was registered by Monsanto as Bollgard, and targeted to tobacco budworm, Heliothis virescens (Fab), bollworm, Helicoverpa zea (Boddie), and pink bollworm, Pectinophora gossypiella (Saunders). The Cry3A protein in potato, Solarum tuberosum, was registered by Monsanto as NewLeaf, and targeted against Colorado potato beetle, Leptinotarsa decelineata Say. The Cry1Ab protein was registered by Monsanto as Yieldgard, for full commercial use in field corn, Zea maize. The Cry1Ab protein was registered by Syngenta Seeds, Inc. as YieldGard and Attribute for full commercial use in field and sweet corn, respectively. Bollgard cotton was first grown commercially in the US in 1996, and in 2000 was grown on 1.5 million ha, and cotton with this gene plus a herbicide resistant gene(s) was grown on 1.7 million ha primarily in USA, China, Australia, Mexico, and South Africa. In China 3 million small farmers grew transgenic insect resistant cotton in 2000 on 500,000 ha. Transgenic corn, first planted in the US in 1996, was grown on 6.8 million ha in 2000 with 92% of this in the US. Profits increased, less insecticides were applied, preservation of beneficial insects was improved, and increased wildlife benefits occurred from use of transgenic cotton and corn. Ten different Bt genes encoding different toxins have been engineered into 26 species of plants. Over 240 insecticidal proteins produced by various strains of B. thuringiensis have been classified. Toxins from the vegetative growth phase of B. thuringiensis and B. cerus, plant amylase inhibitors, plant lectins, chitinases and animal serine protease inhibitors are also being investigated for use in transgenic plants.