Natural rice also known as Oryza sativa when introduced with foreign gene is known as genetically modified rice, created by Ingo Potrykus, it's the transgenic variety of rice better in many ways as compared to the natural rice. Different varieties of GM rice have been produced. Rice is the staple food of Asia which includes countries like Bangladesh i.e. the largest producer of rice; half of the world's population feeds on rice. Genes are inserted in edible parts of rice to produce beta-carotene which further produces pro-vitamin A. Details regarding golden rice were published in 2000 in a magazine, later with the advancement in the field of biotechnology another variety of transgenic rice was produced known as golden rice 2, having 23 times more beta-carotene than the original golden rice. It was a breakthrough in the field of biotechnology. This rice has not been introduced to general public for use yet.
Beta carotene was to be produced from golden rice which further gives vitamin A, endosperm is consumed by human beings, beta carotene is involved in photosynthesis, and it's a carotenoid pigment i.e. produced is leaves and not in endosperms as site of photosynthesis are leaves. But in genetically modified rice beta carotene is produced in endosperm, the edible part of rice crop. Gene was obtained from Narcissus pseudonarcissus, which gave psy (phytoene synthase) and soil bacteria Erwinia uredovora gave the crtl genes. Endosperm-specific promoter controlled the inoculation of psy and ctrl genes in the genome of rice. End product of the whole chain is Vitamin A i.e. retinol which is produced in the stomach of animals by the precursor beta carotene. This project started in 1992 and finally a milestone was written down in the history in the year 2000.
Phytoene synthase | crt1 | lycopene cyclase
Geranylgeranyl-PP------------- phyoene+2pyrophosphate----- zeta-carotene----lycopene
Lycopene then further gives alpha carotene and beta carotene.
Phytoene synthase, crtl, lycopene cyclise are the enzymes that take part in this transformation. Enzyme causes the swift production of beta carotene which is converted in to vitamin A in the stomach of animals, end product is lycopene, if lycopene accumulated like that in tomatoes then the colour of the rice would be red, it's observed that lycopene of the rice is converted in to beta carotene by endogenous enzymes, hence called golden rice or SGR1.
• GM rice has more yields as compared to the wild rice, scientists compared the per hectare productivity of both crops and found GM crop to be 15 times more productive than the wild rice. They will solve the problem of food shortage throughout the world
• They are easy to cultivate as they don't take longer period to ripe hence are harvested in shorter duration.
• They yield high levels of vitamin A also known as retinol, eradicating the deficiency of vitamin A from the world, retinol keeps the moisture level of body in balance, monitors the light adjustability of eyes, neutralizes the free radicals in the body by acting as an antioxidant. Beta carotene a precursor of retinol is found to useful in treat of CAD (coronary artery disease). Beta carotene is produced by this crop which is converted in to retinol in digestive system of animals. Deficiency of vitamin A in human beings can lead to blindness; most vulnerable to these syndromes are children and pregnant women.
• Vitamin A supplements are very expensive so it's a cheap way of producing vitamin A naturally in our food.
• They are resistant to many other things like agrochemicals, bacteria, viral attack etc. They produce grain having high nutritional value and also prevent us from the use of expensive agro chemicals to kill agricultural foes. They are resistant to many other unfavourable circumstances like viral attack, fungal attack etc.
As they are new and have not undergone many tests, so we are not aware of the harmful side effects they can have on human health. They can cause many types of allergies in humans leaving them sick. Scientists are confused about the amount of vitamin A available to the people after proper cooking of this golden rice. People will stop consuming wild rice once this golden rice is made public so we'll lose the natural rice. They are low in nutritional value as compared to the wild rice except the beta-carotene because they are modified to produce higher beta carotene.
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