A soil bacterium produces a lethal toxin which kills insects as they chew their way into a plant
OF LATE, Bacillus thuriengiensis, a
soil bacterium, has become a microbiologist's hot property, owing to its
ability to make a protein toxin (13t)
which selectively kills an insect consuming this protein. The sensitivity
of these insects which include mosquitoes, beetles, butterfly- larvae and
aphids, depends upon the genotypes of
the insect and the bacteria. Efforts of
many research laboratories, both in
Denmark and abroad, have revealed
the factors governing the biology of
bacterial virulence and its interaction
with the insect and also about the
gene encoding for Bt toxin (Danish
Environment, No 4).
Since these insects pose a serious threat to agricultural productivity, scientists have been working towards developing a cost-effective and environment-friendly method for the control of insect pests. Pesticide formulations based on Bt cells or spores (dormant cells) for biological control of insects feeding on crop plants offers an alternative to more expensive and hazardous chemical pesticides.
In Denmark, scientists working at the National Environment Research Institute and the Royal Agricultural University have shown the efficacy of these biopesticides in controlling white -butterfly- larvae infestation in cabbage fields. Another way of using Bt toxin is by inserting it in the plant itself and making a pest-resistant, transgenic (having genetic material from an unrelated species) crop plant.
The bacterial toxin gene, when made to produce the protein inside the plant cell, will work in the same way as it does under natural conditions. Moreover, by making genetically wise alterations in the structure of the gene, the time and site of toxin expression in the crop plant can be regulated. Cotton, corn and potato are three major crops anticipated to hit the market as Bt transgenics in the near future.
We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.
Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.