Food is a human basic need, which is still quite a challenge to meet due to different factors. Commercial and subsistence farmers face forces beyond them such as unreliable water patterns, pests and diseases in their quest to produce enough food. The introduction of insecticides and herbicides together with good farming methods like crop rotation, intercropping, irrigation helped and did indeed revolutionise arable farming. Insects which feeds and also can poison on crops and weeds which compete with crops for water, nutrients and sunshine, can lead to heavy losses of crops if they are not controlled. Insects and weeds have been successfully controlled by Insecticides and herbicides that are sprayed directly on crops to kill the parasites that feed off and compete with them.
However with more advances in science research and knowledge on environmental and health issues, the environment and human health have to be well managed. This thus includes not introducing harmful substances to the environment as they can bio-accumulate and result in an unhealthy environment. Unfortunately, the same is true for insecticides as they are mainly applied by being sprayed directly onto the crops. A good example is DDT (dichlorodiphenyltrichloroethane), which was targeted for insects and some birds but ended up being banned after it was linked to Parkinson's disease. Although advances are being made to produce more specific or target insecticides , not a lot of those are really feasible as most insects or rather organisms are related in general and what is harmful to one might be even be harmful to others that are not being targeted. This also poses danger and a threat to biodiversity. This then calls for ways in which crops that are more resistant, tolerant and maybe even capable of killing their parasites, can be engineered.
Biotechnology, through genetic engineering, where genetic makeup of organisms can be manipulated by either altering the genes that already exists in organisms or introducing ones from other organisms into a different one, can be used to overcome such undesirable effects of insecticides. Thus by making plants that are more resistant, tolerant and that can produce toxins that can kill only the targeted parasite but not harmful to the plant and the consumers, this challenges can be overcome. This can be done by transforming plants with genes that will produce toxins to kill off insecticides but safe for human consumption and without any harmful chemicals being released to the environment.
Bacillus thuringiensis (Bt) is soil bacteria that produce toxins that are toxic to specific insects which have an alkaline digestive tract, such as lepidopterans, dipterans and coleopterans but not toxic to beneficial insects, birds and humans. The proteins that lead to the production of this toxin have been identified as crystalline inclusion bodies that the bacteria produce during sporulation, referred to as Cry and Cyt protein and a third one Vip protein, which is produced during bacterial growth. These proteins are toxins only when ingested by the insect as they are activated in the gut of the insect resulting in the cells destroyed by leaking of ions leading to the gut of the insect breaking down and bacteria multiplying in the insect eventually leading to its death. These proteins thus if introduced into crops, as they act only when ingested by the target insects, will result in a safer environment and will not pose a threat to non problematic insects and other organisms. This have already been done successfully as there are some transgenic plants which were transformed by Bt based toxic proteins such as Cry34/35 in maize and commercialised cotton containing two genes,Cry1Ac and Cry2Ab. The same has been done in tobacco, tomato and potato. The idea behind multiple genes is to make plants to be resistant to a wide spectrum of insects that affect them.
This indeed shows that there are alternatives that can be used that are safer on the consumers, the environment and non problematic organisms as only insects that are targeted by their feeding off the crops and by transforming plants with only genes that target the insects that causes losses to the farmers, are killed as is desired.
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