What is Agricultural Biotechnology?
Biotechnology is often considered synonymous with the biomedical research, but there are many other industries which take advantage of biotech methods for studying, cloning and altering genes. We have become accustomed to the idea of enzymes in our everyday lives and many people are familiar with the controversies surrounding the use of GMOs in our foods. The agricultural industry is at the center of that debate, but since the days of George Washington Carver, agricultural biotech has been producing countless new products that have the potential to change our lives for the better.
Oral vaccines have been in the works for many years as a possible solution to the spread of disease in underdeveloped countries, where costs are prohibitive to widespread vaccination. Genetically engineered crops, usually fruits or vegetables, designed to carry antigenic proteins from infectious pathogens, that will trigger an immune response when ingested.
An example of this is a patient-specific vaccine for treating cancer. An anti-lymphoma vaccine has been made using tobacco plants carrying RNA from cloned malignant B-cells. The resulting protein is then used to vaccinate the patient and boost their immune system against cancer. Tailor-made vaccines for cancer treatment have shown considerable promise in preliminary studies.
Plants are used to produce antibiotics for both human and animal use. Expressing antibiotic proteins in livestock feed, fed directly to animals, is less costly than traditional antibiotic production, but this practice raises many bioethics issues because the result is widespread, possibly unnecessary use of antibiotics which may promote the growth of antibiotic-resistant bacterial strains.
Several advantages to using plants to produce antibiotics for humans are reduced costs due to the larger amount of product that can be produced from plants versus a fermentation unit, ease of purification, and reduced risk of contamination compared to that of using mammalian cells and culture media.
There is more to agricultural biotechnology than just fighting disease or improving food quality. There are some purely aesthetic applications and an example of this is the use of gene identification and transfer techniques to improve the color, smell, size and other features of flowers.
Likewise, biotech has been used to make improvements to other common ornamental plants, in particular, shrubs and trees. Some of these changes are similar to those made to crops, such as enhancing the cold resistance of a breed of tropical plant, so it can be grown in northern gardens.
The agricultural industry plays a large role in the biofuels industry, providing the feedstocks for fermentation and refining of bio-oil, bio-diesel, and bio-ethanol. Genetic engineering and enzyme optimization techniques are being used to develop better quality feedstocks for more efficient conversion and higher BTU outputs of the resulting fuel products. High-yielding, energy-dense crops can minimize relative costs associated with harvesting and transportation (per unit of energy derived), resulting in higher value fuel products.
Plant and Animal Breeding
Enhancing plant and animal traits through traditional methods like cross-pollination, grafting, and cross-breeding is time-consuming. Biotech advances allow for specific changes to be made quickly, on a molecular level through over-expression or deletion of genes, or the introduction of foreign genes.
The latter is possible using gene expression control mechanisms such as specific gene promoters and transcription factors. Methods like marker-assisted selection improve the efficiency of "directed" animal breeding, without the controversy normally associated with GMOs. Gene cloning methods must also address species differences in the genetic code, the presence or absence of introns and post-translational modifications such as methylation.
Pest Resistant Crops
For years, the microbe Bacillus thuringiensis, which produces a protein toxic to insects, in particular, the European corn borer, was used to dust crops. To eliminate the need for dusting, scientists first developed transgenic corn expressing Bt protein, followed by Bt potato and cotton. Bt protein is not toxic to humans, and transgenic crops make it easier for farmers to avoid costly infestations. In 1999, controversy emerged over Bt corn because of a study that suggested the pollen migrated onto milkweed where it killed monarch larvae that ate it. Subsequent studies demonstrated the risk to the larvae was very small and, in recent years, the controversy over Bt corn has switched focus, to the topic of emerging insect resistance.
Not to be confused with pest-resistance, these plants are tolerant of allowing farmers to selectively kill surrounding weeds without harming their crop. The most famous example of this is the Roundup-Ready technology, developed by . First introduced in 1998 as GM soybeans, Roundup-Ready plants are unaffected by the herbicide glyphosate, which can be applied in copious quantities to eliminate any other plants in the field. The benefits to this are savings in time and costs associated with conventional tillage to reduce weeds, or multiple applications of different types of herbicides to selectively eliminate specific species of weeds. The possible drawbacks include all the controversial arguments against GMOs.
In an effort to improve human health, particularly in underdeveloped countries, scientists are creating genetically altered foods that contain nutrients known to help fight disease or malnourishment. An example of this is Golden Rice, which contains beta-carotene, the precursor for Vitamin A production in our bodies. People who eat the rice produce more Vitamin A, an essential nutrient lacking in the diets of the poor in Asian countries. Three genes, two from daffodils and one from a bacterium, capable of catalyzing four biochemical reactions, were cloned into rice to make it "golden". The name comes from the color of the transgenic grain due to overexpression of beta-carotene, which gives carrots their orange color.
Abiotic Stress Resistance
Less than 20% of the earth is arable land but some crops have been genetically altered to make them more tolerant of conditions like salinity, cold, and drought. The discovery of genes in plants responsible for sodium uptake has lead to the development of knock-out plants able to grow in high salt environments. Up- or down-regulation of transcription is generally the method used to alter drought tolerance in plants. Corn and rapeseed plants, able to thrive under drought conditions, are in their fourth year of field trials in California and Colorado, and it is anticipated that they'll reach the market in 4-5 years.
Industrial Strength Fibers
Spider silk is the strongest fiber known to man, stronger than Kevlar (used to make bullet-proof vests), with a higher tensile strength than steel. In August 2000, Canadian company Nexia announced the development of transgenic goats that produced spider silk proteins in their milk. While this solved the problem of mass-producing the proteins, the program was shelved when scientists couldn't figure out how to spin them into fibers like spiders do. By 2005, the goats were up for sale to anyone who would take them. While it seems the spider silk idea has been put on the shelf for the time being, it is a technology that is sure to appear again in the future, once more information is gathered on how the silks are woven.