Useful Features of a Successful Transformation Vector
Crop improvement is been the main strategy for a farmer. Rediscovery of Mendels laws of Heredity at the very beginning of the last century and the subsequent intensive researches have clarified many good details about the very structure and function of DNA as the basis for all demonstrated characters and functions of plants and all organisms. New methods have been developed and used commercially for genetic improvements and modifications of crops in agriculture and simpler and sure faster molecular methods of health care approaches and production of medicinally important molecules medicine. One basic idea is that the sub-cellular genetic factors (discreet DNA sequences) constitute the structure and functions of all the organisms. Discovery of exhaustive DNA related information prompt attempts to find useful genes and introduce into the desired host plants. Well worked techniques are now available and are proving as valuable. Till recently it was found necessary to insert foreign useful DNA into organisms suffering from lack such characters and after the 1980s several methods have been developed and are still being developed for DNA introduction into a host crop plant.
Methods for Delivery of Foreign DNA
In most situations transformations have been carried on of full plants under aseptic conditions at the cellular sub-cellular levels. After this the cells or the tissues transformed are promoted by suitable growth media for the formation of full plantlets which are then taken out to the natural conditions and tested in detail before entering them into plant breeding programs. The other feature is that a marker genes, such as genes for antibiotic resistances, are integrated with the gene sequence to be introduced.
Agrobacterium mediated transformation Understanding the mechanism of crown gall (tumor) formation particularly in many dicotyledonous plants was the origin of this technology. Agrobacterium tumefaciens bacterium has the natural capability of introducing its DNA (T-DNA) into the infected cells where the integrated DNA piece produces two basic plant growth hormones auxins and cytokinins, both of which promote cell division which do not dor any normal structures such as shoots. A related species A. rhizogenes has the capability of promoting numerous root growths. This mechanism has been used in several plant species after the genes for tumor growth have removed by molecular methods to form a disarmed vector.
Biolistic- A tissue or cells to be transformation are exposed to high velocity bullets coated the foreign DNA.
This is an often used method
Electroporation As in biolosistics but the movement of the DNA is also forced or promoted by an electric charge.
Calcium Chloride methods. The cells to be transformed are sensitized such as with different extreme temperature regimes. Such cells are exposed for brief times to a calcium chloride solution which facilitates channels in the cell membranes for DNA entry.
Other methods There are many other methods which have been developed but not used often. They are silicon carbide based, micro-injection, polymers, and others.
A Successful Vector A good vector has to carry DNA safely till the DNA is released into appropriate site.
The DNA has to be stably integrated into the host cells. The DNA should be functional and express effectively in the host cell without disturbing the original genetic function of the host DNA.
Agrobacterium has the advantage that it can also be used in normal conditions without the need for aseptic conditions. This bacterium is versatile in the sense it can transfect any and all the kinds of cells and tissues.
There have been many reports which demonstrate that even seedlings grown in non-aseptic conditions can also can be transfected.
Methods for Delivery of Foreign DNA
In most situations transformations have been carried on of full plants under aseptic conditions at the cellular sub-cellular levels. After this the cells or the tissues transformed are promoted by suitable growth media for the formation of full plantlets which are then taken out to the natural conditions and tested in detail before entering them into plant breeding programs. The other feature is that a marker genes, such as genes for antibiotic resistances, are integrated with the gene sequence to be introduced.
Agrobacterium mediated transformation Understanding the mechanism of crown gall (tumor) formation particularly in many dicotyledonous plants was the origin of this technology. Agrobacterium tumefaciens bacterium has the natural capability of introducing its DNA (T-DNA) into the infected cells where the integrated DNA piece produces two basic plant growth hormones auxins and cytokinins, both of which promote cell division which do not dor any normal structures such as shoots. A related species A. rhizogenes has the capability of promoting numerous root growths. This mechanism has been used in several plant species after the genes for tumor growth have removed by molecular methods to form a disarmed vector.
Biolistic- A tissue or cells to be transformation are exposed to high velocity bullets coated the foreign DNA.
This is an often used method
Electroporation As in biolosistics but the movement of the DNA is also forced or promoted by an electric charge.
Calcium Chloride methods. The cells to be transformed are sensitized such as with different extreme temperature regimes. Such cells are exposed for brief times to a calcium chloride solution which facilitates channels in the cell membranes for DNA entry.
Other methods There are many other methods which have been developed but not used often. They are silicon carbide based, micro-injection, polymers, and others.
A Successful Vector A good vector has to carry DNA safely till the DNA is released into appropriate site.
The DNA has to be stably integrated into the host cells. The DNA should be functional and express effectively in the host cell without disturbing the original genetic function of the host DNA.
Agrobacterium has the advantage that it can also be used in normal conditions without the need for aseptic conditions. This bacterium is versatile in the sense it can transfect any and all the kinds of cells and tissues.
There have been many reports which demonstrate that even seedlings grown in non-aseptic conditions can also can be transfected.
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