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India: ICAR Developing Transgenic Cotton
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Harish Damodaran The Central Institute for Cotton Research (CICR), Nagpur, claims to have already evolved its own transgenic cotton versions, involving introduction of two Bt genes, cry1Ab and cry1Ac, into two popularly grown local cotton varieties, LRA 5166 and LRK 516 (Anjali). "We have achieved successful transformation in our transgenics, with the Bt genes being stably integrated into the plant cells. Our glasshouse already has around 1,000 plants. We will soon be seeking the Department of Biotechnology's (DBT) permission to undertake limited field trials", the CICR Director, Dr. M.S. Kairon, told Business Line. He said that unlike Mahyco's genetically engineered cotton, which had involved back-crossing Monsanto's 'Cocker-310' variety in the US (bearing the Bollgard cry1Ac gene) into its own hybrid lines such as Mahyco 4 and 11, the CICR transgenics were a product of direct induction of the Bt genes into its locally developed varieties. "Also, the methods of incorporating the foreign genes have been different. While Monsanto/Mahyco have employed the particle gun bombardment route, we have used Agrobacterium tumefaciens (a natural genetic engineering media) to introduce the genes into plant cells", Dr. Kairon said. If things go well, the CICR transgenics would reach the farmers' fields in about two years, he said, while adding that the institute would be willing to even license its technology to domestic private seed companies for commercial scale production. Mahyco, on the other hand, has already conducted limited field trials of its back-crossed transgenics under the supervision of DBT's Monitoring and Evaluation Committee (MEC). Based on the bio-safety data generated from the small-scale trials, DBT had recommended to the Ministry of Environment and Forests to allow the company to undertake large-scale open field trials in various agro-climatic regions of the country - the permission for which has now been granted by the Genetic Engineering Approval Committee (GEAC) in the Ministry. Monsanto's patented Bollgard cotton as well as the CICR's proposed transgenics are said to possess 'in-built' resistance against the deadly insect pest, Helicoverpa armigera or American bollworm. This, in turn, is claimed to significantly reduce the need to resort to frequent and excessive spraying of chemical pesticides (cotton accounts for an estimated 55 per cent of pesticide consumption in India, despite being grown on less than five per cent of its gross cropped area). The Bt genes, incorporated in the transgenics, are isolated from a naturally occurring soil bacteria, Bacillus thuringiensis, more than 100 strains of which are found in Indian soils alone. These genes are known to synthesise a variety of crystal proteins that exhibit specific toxicity towards lepidopteran (flying) insect pests, including the havoc-causing Heliothis and Helicoverpa species (often referred to as the 'bollworm complex'). Lepidopteran pests usually lay eggs on the leaves of the plant and it is the hatched larvae that bore into the growing fruits and shoots. Plants that have the Bt gene produce specific proteins which cannot be broken down by enzymes present in the digestive tracts of lepidopteran insects. Instead, when the bollworm pest feeds on the cotton plant, the Bt proteins bind with specific receptors present in the insect's guts and do not get digested. As a result, the larvae stop feeding and eventually die.
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