WHAT ARE TRANSGENIC PLANTS? THEIR APPLICATIONS, RISKS, CONCERNS AND REGULATIONS:-
As the population of the world is increasing day by day and there is a need to use the modern biological techniques to increase the food production to feed the increasing population, the use of these biological techniques leads to the production of transgenic plants. Transgenic plants are those plants which contain a gene or genes that have been introduced artificially from a foreign source into the plant’s genetic makeup using a set of biotechnological techniques. Using biotechnological techniques a large number of transgenic plants have been produced, some of which are as follows.
GOLDEN RICE (A rich source of carotene)
As we know that rice is a staple food in many parts of the world, regions where people are poor and rice forms the major part of their diet, deficiency of vitamin A is common which causes blindness.
Vitamin A is present in the aleuronic layer of rice grains. This layer goes rancid if the rice is stored for any length of time which is why this layer is removed and rice is polished to produce white rice.
In the 1990’s a project was undertaken to produce rice that contain vitamin A. Genes encoded for vitamins A were isolated from daffodils and Erwinia uredovora and were inserted into rice cells by Agrobacterium tumefaciens mediated gene transfer. This genetically modified rice is called Golden rice, because it contains a lot of orange pigment that is carotene.
Finally the genetically modified rice was bred with the other varieties of rice to produce varieties that could grow well in the conditions, in different parts of the world.
Apart from the increased production, transgenic plants have other advantages too. By transferring the right genes, plants can serve as bioreactors to modify compounds such as amino acids, proteins, vitamins, plastics, pharmaceuticals (peptides and proteins), drugs, and enzymes for food industry and so on.
Tobacco is the most preferred plant as a transgenic bioreactor. It can be easily transformed and engineered. Tobacco is an excellent biomass producer with about 40 tons of fresh leaf production as against rice with 4 ton.
The seed production is very high approximately 1 million seeds per plant and it can be harvested several times in a year.
Another invention of biotechnology is the transgenic bioreactors to express antigens which can be used as edible vaccines. Genes encoding antigenic proteins from the pathogens are isolated and expressed in plants. Such transgenic plants can be eaten for vaccination/immunization and are called edible vaccines.
Transgenic varieties of tomatoes and potatoes have been developed for expressing antigens derived from animal viruses. The examples are rabies virus, herpes virus. The first clinical trials in humans using a plant derived vaccine were conducted in 1997 and were met with limited success.
Polyethenes and plastics are one of the main environmental hazards. Efforts around to explore the possibility of using transgenic plants for biodegradable plastics, transgenic plants can be used as factories to produce biodegradable plastics like polyhydroxy butyrate or PHB.
Genetically engineered Arabidopsis plants can produce PHB globules exclusively in their chloroplasts without effecting plant growth and development. The large scale production of PHB can easily be achieved in plants like populous where PHB can be extracted from leaves.
Future envisaged applications of GMO’s are diverse and include drugs in food such as bananas that produce human vaccines against infectious diseases such as Hepatitis B.
RISKS AND CONCERNS:-
There are issues and concerns regarding the use of transgenic plants and their effects on the health and environment.
Genetically modified crops can be inherently dangerous and can cause allergies, for example, a soybean engineered to contain genes from a brazil nut was found allergic to humans.
Although the soya was intended for animal feed citing the potential difficulties of preventing the soya from entering the human food chain, a decision was taken not to pursue the development of this soybean.
Genetically modified crops can indirectly promote antibiotic resistance, making it difficult to treat human disease. Transfer of resistance gene from transgenic food to microorganisms that normally live in our stomach and intestines, or to bacteria that we ingest along with food, could help those micro-organisms to survive an oral dose of antibiotic medicine.
Hybridization of crops with nearby weeds may enable weeds to acquire traits such as resistance to herbicides. Genes that provide a competitive edge, such as resistance to viral disease, may get inherited by weeds and could benefit them.
There is also concern that transgenic plants growing in the field will transfer their antibiotic resistance genes to soil micro-organisms, thus causing a general increase in the level of antibiotic resistance in the environment.
CHANGING THE SOIL CHEMISTRY:-
Many plants leak chemical compounds into the soil through their roots. There are concerns that transgenic plants may leak different compounds into the soil than conventional plants do thereby changing the soil chemistry.
The roots of BT. plants have been found to release a toxin into the soil following harvest decaying plant still contain some amount of this toxin.
CHANCES OF CROSS POLLINATION:-
Many crops plants disperse pollen which may be carried by winds or insect pollinators. So that genetically engineered plants may cross-pollinate non-engineered plants, introducing the new genes into wild plant populations and into the ecosystem, thus affecting the food chain with several levels of consumers.
Farmers whose fields are near genetically modified crops may not be able to certify their crops as organic.
SYSTEM OF REGULATION OF TRANSGENIC CROPS:-
In developed countries there is good system to regulate the transgenic crops such as the system for regulating transgenic crops in the US is complex and evolving.
Transgenic crops are regulated at every stage in their development, from research planning through field testing, food and environment safety evaluations, and international marketing by three federal agencies- The U.S. Department of Agriculture (USDA), the U.S. Food and Drug Administration (FDA), the U.S. Environmental Protection Agency (EPA). But in Pakistan a strong regulatory system, trained staff and well-equipped laboratory to deal with the issues involving transgenic plants are not present.
The safety of the produce from transgenic plants is a matter of great concern and considerable debate, it may be projected that transgenic plants will play an important role in world agriculture and most slightly will become an industry during the coming years.
B.Sc. (Hons) Agricultural Sciences,
Center for Agricultural Biochemistry and Biotechnology (CABB),
University of Agriculture Faisalabad.
Email: [email protected]
Mubashir Abbas*, Syed Ikram Ali Shah1, Manzoor ul Hassan2.
1Co-Authors, Center for Agricultural Biochemistry and Biotechnology, University of Agriculture Faisalabad.
2Co-Author, Institute of Horticultural Sciences, University of Agriculture Faisalabad.