Learn about Biotechnology
Technology has dramatically changed the nature of working with living things; and far from being at an end, those changes continue to happen.
It is impossible to predict the future of biotech applications to horticulture; but that doesn't mean you cannot become prepared for that change; and benefit from biotech change.
This course helps you to understand and become aware of what has happened and is continuing to happen with respect to biotechnology applications in the horticultural industry.
Learn about Genetic Engineering and other Biotech Applications
Genetic engineering is the insertion of a foreign synthetic gene (DNA) into a plant, with subsequent expression of the gene to produce a new phenotype. The source of the gene may, in theory, be from any organism - it does not have to be from a plant of the same species. Genetic engineering may be considered as speeding up the natural process of mutations. Although most mutations are of no benefit, or in fact harmful, to the organism, sometimes one comes along which is beneficial. It is possible to insert these mutated genes into another plant.
Genetic engineering has been made possible by the development of gene cloning (also known as recombinant DNA) and associated molecular biology techniques. A gene isolated from one species can be inserted into a bacterial or yeast ‘vector’ DNA molecule to make a recombinant molecule. Vectors include plasmids and bacteriophage. In other words, mutated genes cause changes in an organism by changing the sequences in the DNA molecules. As such, the production of a particular protein may be blocked in the organism, or a different protein may be produced.
Many copies of vectors (with gene inserts) can be produced and purified, allowing subsequent manipulation of the clonal gene(s). Identification and validation of gene function must be carried out, to ensure the correct gene has been cloned for, before subsequent insertion into the recipient plant’s genome.
Four methods have been successfully used to produce transgenic (genetically modified/genetically engineered plants. These are:
- Agrobacterium - mediated gene transfer
- Biolistics - micro-projectile bombardment
- Protoplast-based direct gene transfer
The two main methods, Agrobacterium–mediated transformation and Biolistics, are described below.
Agrobacterium-mediated Gene Transfer
This technique makes use of a naturally occurring gene transfer system that evolved in a genus of bacteria to aid the colonisation of plant tissues. The gene to be transferred to plants is transferred into an Agrobacterium plasmid, and plant tissue inoculated with Agrobacterium bacterial culture carrying the transferred gene. Entire plants can be regenerated from ‘transformed’ cells using tissue culture, or in some cases reproductive cells may be transformed in the flower.
Limitations of this technique include:
- The requirement of successful plant tissue culture regeneration systems for most species.
- Agrobacterium does not readily infect the cells of monocots, such as cereals, and some important dicot species, such as soya beans.
Biolistics (particle or gene gun)
With this system, tiny heavy metal (e.g. gold) micro-particles are coated with the DNA to be inserted and integrated into the plant genome. The micro particles are fired into the target plant tissue. Genes can thus be ‘shot’ into almost any type of cell of tissue. Whole plants are then regenerated from isolated tissues, or in some cases biolistic treatment of plant meristems can yield transgenic plants.
Problems with Genetic Engineering
Whilst genetic engineering may be used to create new varieties of plants, there are risks associated with artificially moving a gene from one plant or species to another. For instance, it can harm the recipient plant by causing unpredicted outcomes. Unwanted changes might also find their way into surrounding populations and spread uncontrollably. If this happens then conceivably the original population may be changed and genes lost.
There are also ethical dilemmas involved. For example, some would argue that it is wrong to play around with genes and transfer them from one species to another, or to create new species. Some people do not feel comfortable eating food crops with have been genetically modified.