Plant Genetic Engineering Introdution -

Genetic engineering of plants is rapidly becoming a reality and plant gene transfer is now a fertile field. Genetic engineering involves manipulation of the genetic material toward a desired end in a directed and predetermined way.

This is alternately called recombinant DNA technology or gene cloning. Strictly speaking, to "engineer" means to design, construct and manipulate to a set plan. Genetic engineering involves isolation of DNA fragments within a cell recombining them outside it. The basic technique is quite simple.

Millions of identical cells, i.e., cell clones, eventually arise. Consequently, it is possible to obtain millions of copies of a specific region of DNA inside a bacterial cell by allowing the cell (and the piece of DNA) to multiply millions of times. A similar process takes place in plant cells also but in a slightly different way. We shall consider this later.

Current interest in genetic engineering centres on its various applications, such as:

(1) isolation of a particular gene, part of a gene, or region of a genome;
(2) production of particular RNA and protein molecules in quantities formerly thought to be unobtainable;
(3) improvement in the production of biochemical’s (such as enzymes and drugs) and commercially important organic chemicals;
(4) production of varieties of plants having particular desirable characteristics (for example, requiring less fertilizer or being resistant to disease);
(5) correction of genetic defects in higher organisms; and
(6) creation of organisms with economically important features (for example, plants capable of maturing faster or having greater yield).

3) Transfer of the recombinant vectors into bacterial cells, either by transformation or by infection using viruses.

4) Selection of those cells which contain the desired recombinant vectors.

5) Growth of the bacteria, which can be continued indefinitely, to give as much cloned DNA as needed.

6) Expression of the gene to obtain the desired product.

In short, gene cloning or genetic engineering is essentially the insertion of a specific piece of "foreign" DNA into a cell in such a way that the inserted DNA is replicated and handed on to daughter cells during cell division. The basic mechanism of genetic engineering is discussed below, followed by some details regarding plant genetic engineering.