Genetically modified plants, fungi and animals are used in the fields of agriculture, therapeutics, diagnostics, waste treatment, food processing, bioremediation and energy production. Biotechnology operates by creating catalysts such as microbes and pure enzymes and providing optimal conditions for them to act. It also provides downstream processing technologies to purify protein and organic compounds.
The use of conventional breeding, organic farming and agrochemicals hasn’t increased the food production or its quality to substantiate the growing population In such situations, genetic engineering techniques have been used to alter the genes of many plants, bacteria, fungi and animals, which are called Genetically Modified Organisms or GMOs. Genetically modified or GM plants have higher tolerance to abiotic stress such as cold, drought, salt and heat and are pest-resistant. GM crops are with enhanced nutritional value, such as Vitamin A-enriched rice plants.
The greatest contribution of biotechnology to the field of agriculture is the production of pest-resistant plants. For example, Bt toxin produced by a bacterium called Bacillus thuringiensis has been cloned and expressed in many plants to make them insect-resistant. Once an insect ingests the toxin, the toxin converts into active form due to the alkaline pH of the gut and creates pores in the gut, causing its death. The choice of Bt toxin depends on which pest is targeted.
A pest resistance method against nematodes or round worms is RNA interference, which is a cellular defence in all eukaryotic organisms. For example, a nematode named Meloidegyne incognitia infects the roots of tobacco plants and leads to a drastic reduction in the crop yield. This method involves the silencing of a specific messenger RNA of the nematode due to a complementary double-stranded RNA molecule. The source of this complementary RNA could be through viruses having RNA genomes or transposons.
Using Agrobacterium vectors, nematode-specific genes are introduced into the host tobacco plant. The introduction of DNA is such that it produces both sense and anti-sense RNA in the host cells. Since these two RNAs are complementary to each other, they form a double-stranded RNA that initiate RNA interference. As a result, the messenger RNA of the nematode is silenced. Consequently, the parasite is not able to survive in a transgenic or genetically engineered host expressing specific interfering RNA.