Genetic Engineering in Plants,Monocot Plants,Biotechnological Methods,Tailored Vector,Viral Pathogens,Gene Expression,Genetic Manipulation,Transgenic Plants

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Gene Engineering in Plants
Biotechnological Problems Associated with Plants
Ti Plasmid Without Tumorgenic Genes
Cloning Plastid and Mictochondrial Genes

	Genetic Engineering in Plants - The ability to isolate and clone genes, coupled with the development of reliable techniques for introducing genes into plants, has opened a new route to genetic improvement of plants that can circumvent the limitations of conventional breeding methods. Once a useful gene is isolated, it can be transferred to many different crops without a lengthy breeding program. Such useful traits as resistance to herbicides and disease have been identified and by gene transfer herbicide resistant and disease-resistant plants have been produced.
Gene transfer into dicot plants can generate varieties with improved agricultural qualities and novel traits. Genetic engineering of monocot plants, which include the world's major cereal crops, involves certain difficulties. However, these difficulties are now being resolved at a quicker pace by developing other biotechnological methods such as electroporation through a tailored vector. Nevertheless, the long-standing inability to regenerate whole plants from transformable cells of monocots and legumes still remains an obstacle to successful genetic engineering programs.
A model genetic engineering of a plant comprises the following general steps: (1) selection of a plant gene whose introduction in other plants would be of positive agricultural value; (2) identification and isolation of such genes; (3) transference of isolated genes to the plant cell; and (4) regeneration of complete plants from transferred cells or tissues. Successful attempts at introducing disease, herbicide and pesticide resistance in plants following the aforesaid steps have already been reported from several laboratories.
Some of the goals of plant genetic engineers include production of plants that are (a) resistant to herbicide, insect, fungal and viral pathogens, (b) improved protein quality and amino acid composition, (c) improved photosynthetic efficiency, and (d) improved post harvest handling. But why do we wish to clone plant genes? Firstly, molecular cloning of genes allows the investigation of gene structure and the sequences which control gene expression. Cloning provides the basic information which forms the starting point for many more sophisticated studies. Further, gene cloning technology may find a place in the manipulation of plants for exploitation by human beings. This technology could provide an additional tool for the plant breeder who is trying to improve crops by traditional methods.
	In addition, plants can be viewed as a genetic resource, genes being cloned into, and expressed in bacteria. These bacteria may then be used to produce desirable plant products on an industrial scale using fermenters. The first transgenic plants expressing engineered foreign genes were recovered in 1984. Dramatic progress has been made in the last few years in the development of a gene transfer system for higher plants. About 20 crops can be genetically engineered at present.

Rapid progress is being made in the genetic manipulation of many species and almost every month another successful plant transformation is reported.

Cereals (wheat, rice, maize, barley, sorghum, millets) are clearly the most important group of food plants.

Taken together they provide 52% of the food consumed by people. It is not surprising that cereals are a major target for cellular and molecular genetic manipulation, with particular focus on recovering fertile transgenic plants.