There are many definitions of what a genetically modified organism is. According to the website of the European Commission, genetically modified are organisms obtained by artificially modifying the genetic makeup using modern biotechnology techniques called gene technology (https://ec.europa.eu/food/plant/gmo_en). In all cases, the creation of GMO is related to the use of recombinant DNA techniques to create new combinations of genetic material and the incorporation of this material into the host.
Methods for development of GMO plants
Since the first development of the technology for creating GMO plants nearly 40 years ago, until today a number of improvements in its efficiency and application have been made. The advantage of this method is that genes from one species of organism can be transferred to another species in a way that is impossible to happen naturally through sexual reproduction. For example, a gene from jellyfish or fish may be integrated into the genome of a plant. While it offers exceptional opportunities both for research and for commercial purposes, over the years the technology has been attacked by representatives of various organizations regarding how safe it is from environmental and health perspective and to what extent it is sustained from moral and ethical point of view.
Development of GMO plants by the method of genetic transformation using the bacterium Agrobacterium tumefaciens
Agrobacterium tumefaciens is a soil pathogenic bacterium that has the ability to transmit and integrate part of its DNA (T-DNA) into the genome of certain host plants, thus causing the formation of tumors. The integrated into the plant T-DNA contains genes participating in the synthesis of growth hormones (auxins) that induce growth of the tissues and the formation of tumors. In addition, T-DNA encodes enzymes inducing the synthesis of specific amino acids by the plant called opines which the bacteria can metabolize. The integration of T-DNA into the genome has a semi-random nature. The substitution of T-DNA with a gene from another organism results in its integration into the genome of the host plant. That is what is used by genetic engineers to include new gene in the plant organism. A whole plant can be grown from the resulting transformed plant cell containing the new gene in every cell. The technology is used intensively to study the function of genes with entirely scientific purposes. When the integrated new gene imparts valuable economic characteristics, the resulting plant can be used for commercial purposes.
Genetic transformation using gene gun
The bacterium Agrobacterium tumefaciens has a range of natural hosts, which limits its use as a universal tool for genetic transformation of all plant species. For this reason, other methods for development of GMO plants have been developed, such as the method of the gene gun. In this case, particles of heavy metal (eg. gold) are coated with DNA that is intended to be transferred in the plant organism and the resulting particles are fired using natural gas towards the tissue of the host. The fired particles pierce the cell walls of the plant tissue and deliver the carried by them DNA inside the cell. In many cases, the transferred DNA is successfully integrated randomly into the host genome and from the resulting transformed cell a whole plant can be grown bearing the “new” DNA in every cell.