Transgenic Pants
Transgenic Plants Application. Conventionally, hybridization, mutagenesis & polyploidy produce the genetic variation required for crop improvement. More recently, biotechnological methods, called variation, have become available for some genetic variations. In vitro plant cell culture produces a large amount of genetic variation, known as somaclonal variation, from which a variety of useful variants have been isolated: some of these variants have been associated as commercial varieties. Somatic hybridization is the fusion of protoplasts of selected plant species, which often yields hybrid plants between spices that are sexually incompatible. The somatic hybrids are symmetric or asymmetric: both provide a potential for gene introgression into a crop from a similar spice, but we do not have a commercially active example so far. Another culture yields haploid plants: in a very short period, chromosome doubling of such plants generates homozygous lines.
By mixing another culture with traditional breeding programmers, several commercial varieties have been produced, especially in China. The most potent biotechnological method, however, is the transfer by different transformation techniques of precisely designed gene assemblies: this constitutes genetic engineering. The plants obtained by genetic engineering typically contain a gene or genes from an unrelated organism; such genes are referred to as transgenic plants and transgenic plants are referred to as transgenic plants.
Transgenic Plants Application:
Transgenic plants have both essential and applicable uses that are summarized briefly below:
- In studies on plant molecular biology regulation of gene action recognition of regulatory sequence etc., they have proven to be extremely useful instruments. For instance, T-DNA & transposable elements generate mutations by being inserted into genes and thus acting as ‘molecular tags’ for the identification & isolation of genes. Transgenic plants also allow the study of studies of metabolic pathways & transaction factors in gene function & the elucidation of plant responses to environmental stresses, etc.
To enhance their agronomic & other characteristics,
2.Specefic genes have been transferred into plants.
3 . In order to grow transgenic plants immune to insect viruses, etc., genes for resistance to different biotic stresses have been designed.
- Many gene transfers have been aimed at improving the quality of transgenic plants’ generated protein or lipid quality, etc.
5.Traqnsgenic plants are intended to develop novel biochemicals such as immunoglobulins etc. of interferon insulin or useful biopolymers such as polyhydroxy-butyrate that are not produced by normal plants.
6.Trqabsgenic plants were developed that express a gene from a pathogen encoding an antigenic protein.
GM crops that are resistant to herbicides:
Usage of herbicides in modern agriculture is an effective means of eliminating weeds from cultivated crops. By inactivating target proteins (usually enzymes) important for essential functions such as photosynthesis & other biosynthetic pathways, herbicides exert their action. Herbicides are also non-selective, which restricts their use because crops & weeds have common pathways. Herbicide selectivity can be accomplished by producing particular herbicide-tolerant plants to ensure the protection of crops from the herbicide applied.
In plants, there are two methods for engineering herbicide resistance.
(a)Modification of the target herbicide action enzymes to make them insensitive to the herbicide.
Or
In order to allow normal metabolism despite the presence of herbicide, overexpression of the target protein.
(b) Etoxifying the herbicide by adding the gene that degrades the herbicide prior to its action in plants.
Resistance obtained by the first mechanism has been developed for the herbicide:
— glyphosate
— Atrazine and
— sulfonylureh.
In the second strategy resistance has been obtained against:
— bromoxynil
— phosphinothrycine.
— 2.4 D
History to Technology
How are these herbicides functioning?
These herbicides target key enzymes in the plant’s metabolic pathway that disrupt the production of plant food and ultimately kill it. And how do the plants evoke tolerance for herbicides? Some may have acquired the trait through selection or mutation: or more recently, plants may be modified through genetic modification.
Why the growth of HT crops
What is new is the ability to generate a degree of tolerance for large herbicides that regulate most other green plants, in particular glyphosate & glufosinate. Having two herbicides is beneficial for the management of weeds and has limited direct effects on animal life and is not persistent. They are extremely powerful & among the best to use agrochemicals. They are, sadly, equally successful against crop plants.
Tolerant crops 1.Glyphosate-
By blocking the enzyme EPSPS (5-) and the enzyme involved in the biosynthesis of aromatic amino acids , vitamins & several secondary plant metabolites, glyph sate herbicides destroy plants. There are several methods by which crops can be adjusted to be tolerant of glyphosate. One solution is to add a soil bacterium gene that generates an EPSPS resistant glyphosate. Another approach is to add a separate gene from the soil bacterium that creates a degrading enzyme for glyphosate.
Tolerant crops 2.Glufosinate-
Glufosinate herbicides contain phosphinothricin, the active ingredient that destroys plants by blocking the enzyme responsible for the synthesis of nitrogen and detoxifying ammonia as a result of plant metabolism. Tolerant glufosinate-modified crops contain a bacterial gene that produces an enzyme that detoxifies phosphorus and prevents it from causing damage. Other techniques that genetically alter crops to withstand exposure to herbicides including:
1.Producing a new herbicide detoxifying protein:
2.Modifying the target protein of the herbicide so that the herbicide will not affect it. Or
3.Producing physical or physiological obstacles that prohibit the herbicide from entering the plant. The first two methods are the most common ways in which researchers grow herbicide-tolerant crops.
Advantages of Resistant Herbicide Crops
—Excellent management of weeds & therefore greater crop yields;
—Flexibility to manage weeds later in the growth of the plant;-
—Reduced spray numbers throughout the season;
—Reduced use of fuel (due to less spraying);
—Reduced compaction of the soil (because of less need for spraying on the land);
—Use of compounds of low toxicity which do not remain active in the soil &;
—The opportunity to use no-till or conservation – till scheme, with consequent benefits to soil structure & organisms;
Safety Aspects of Herbicide Tolerance Technology
Town of Toxicity & Allergens:
Government regulatory agencies in many nations have ruled that, relative to their non-GM counterparts, crops with herbicide-tolerant conferring proteins do not face any other environmental & health risks. In compliance with the guidelines established by relevant international organizations, added proteins are evaluated for possible toxic & allergenic activity. They are not recognized toxins or allergens from source with no history of allergen city or toxicity: & they have roles, with are well understood.
Impact on crops:
In contrast to parental crops, the expression of these proteins does not harm the growth of the plant or result in poorer agronomic results. No other metabolic modifications occur in the plant, except for the expression of an additional enzyme for herbicide tolerance or the modification of an already developed enzyme. Crop persistence or invasiveness
A significant environmental problem for herbicide-tolerant crops is their ability to produce new weeds by crossing with wild relatives or merely persisting in the wild. However, this capacity is evaluated prior to implementation & is also tracked after planting the crop. The latest scientific evidence shows that in the absence of herbicide application, GM herbicide-tolerant crops are no more likely than their non-GM counterparts to be invasive in agricultural fields or in natural habitats. There is no evidence of improved persistence in herbicide-resistant crops currently on the market.
Problems with crops resistant to herbicides
- To grow such types of GM(Genetically Modified) crops, you need a lot of chemical substances.
- No other metabolic modifications occur in the plate, except for the expression of an additional enzyme for herbicide tolerance or modification of an already existing enzyme.
- A major environmental problem associated with herbicide-tolerant crops is their ability to produce new weeds by erosing wild relatives or simply persisting in the wild,
- By crossing, the herbicide resistance gene can be passed into the weed from the crops. In such a situation, the weed can become tolerant of herbicides.
