Agricultural Biotechnology Essays Examples

Agriculture is at the heart of the progression of the human race as a distinct species, and our success can be measured directly to our advancements in terms of crop improvement. Agricultural biotechnology has been used to generate plants with novel traits, such as resistance to biotic and abiotic stresses, as well as pests. Plant biotechnology as a discipline entails both molecular plant breeding and the development of transgenic plants. Molecular plant breeding can be accomplished by selecting plants with desirable characteristics using complex molecular techniques such as marker assisted selection. Transgenic plants can be generated either via Agrobacterium-mediated transformation, by which a specific type of soil bacteria harboring the gene of interest as well as a selectable marker can infect plant cells and incorporate the foreign gene into the plant’s chromosome. Transgenic plants can also be generated or by particle bombardment. In this case, small microcarriers which harbor the plasmid of interest are bombarded into plant tissue using a device known as a gene gun [1, 2 and 3]. Cells that have been successfully transformed are then selected on media containing the appropriate selection marker and regenerated into mature plants. There are many applications of biotechnology which have been used successfully in the field of agriculture. A number of them are described in this next section.
One of the most significant successes of agricultural biotechnology has been the introduction of biotech crops which confer herbicide resistance. Transgenic crops which confer glyphosate resistance, for example, can tolerate spraying applications of this mildly toxic pesticide without damage. The result is environmentally friendly as it enables the need for high levels of herbicides to be sprayed on plants to be greatly reduced yet has enabled farmers to manage weeds more effectively [4- 6]. This strategy has become so successful that currently almost 90% of transgenic crops grown around the world possess this trait. More recently, scientists have demonstrated field-evolved glyphosate resistance mutations in corn that take place under selective pressure and recreate the genetic-engineered version [7].
Another important trait that has been developed in crops by agricultural biotechnology is stress tolerance to enable plants to survive in times of adverse environmental conditions, including high temperatures, drought, and even high salinity due to flooding. For example, drought tolerant plants have been developed which can conserve more water by increasing the time of stomatal closure more frequently than conventional plants [8 9]. Other transgenic plants have been generated which express drought tolerance genes, such as molecular chaperones or which help in the synthesis of polyamines, molecules that help plants tolerate abiotic stresses such as drought. These have been generated both by using molecular plant breeding as well as transgenic technologies [10].
Salt tolerant plants have also been produced using agricultural biotechnology. A number of plants which can thrive in high concentrations of salt have been identified and the mechanisms behind their salt tolerance have been characterized. A number of plants were found to highly express stress responsive genes products including transcription factors that help the plant to sequester salt into the vacuoles or block salt entry altogether. These genes can be added to salt sensitive plants to help them survive in times of flooding [11- 13]. For example, the AREB/ABF series of transcription factors have been shown to regulate the abscisic acid-responsive genes which are involved in stress resistance.
A third group of traits that have been examined extensively in agricultural biotechnology are those of crops which are resistant to an assortment of pests and pathogens [14]. Of these, the first commercialized and by far the most infamous are insect resistant transgenic crops expressing the Bt (Bacillus thuringiensis) toxin gene. Insects which ingest this toxin soon die of pores which are created in the alkaline environment of their gut lining (Figure 1). This biological pesticide has been largely used as an environmentally friendly way to protect crops from insects which avoid sprays by burrowing into the plant [15- 17]. However, some controversy remains as to whether Bt corn can exert undesirable effects on non-target arthropods. Recently Guo et al., (2014), evaluated the effect of Bt corn on non target organisms in the field by planting Bt and non-Bt corn in triplicate in a location where no crops had been planted before [18]. One hundred corn plants were grown in each plot, and insect samples were taken and recorded over a period of two years. The results of this study indicated that a statistical analysis of the pattern of distribution of non-target organisms was identical between Bt and non-Bt corn plots (Figure2). The fact that there was no difference between plots indicates that the presence of Bt toxin in corn did not influence the population density of the assessed non-target communities. The authors conclude that while no changes could be observed, longer and larger scale studies must be conducted to ensure that the impact of Bt toxin in crops is negligable.
Another example is the use of the alarm pheromone enzyme (E)-β-Farnesene (EβF) synthase, which specifically targets aphids and causes them to disperse from the plant. [19]. In addition to repelling aphids, the pheromone attracts their natural enemies, including ladybugs and parasitoid wasps.
In conclusion, agricultural biotechnology has been applied to improve crop production under both biotic and abiotic stress conditions. Transgenic plants have been generated which are herbicide tolerant and can withstand adverse environmental conditions due to climate change such as extreme temperatures, drought and flooding. Biotechnology has been used to create plants which can resist a spectrum of pathogens including harmful insects. In general, these improvements can save the farmer money and increase crop yield. A disadvantage of the use of transgenic plants is the length of time required to develop them and test them in field trials before they can be released for public approval. In addition to this, the political environment at present is not always in favor of GMOs, and as a result transgenic plants remain the subject of controversy. Nonetheless, transgenic plants are a necessary part of modern agriculture and will continue to be so for the future success of our civilization.

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