Authors: Deepak V Pawar1, Kishor U Tribhuvan1, Jyoti Singh1
1ICAR-NRCPB, I.A.R.I, New Delhi-12
What is gene switching and how does it work?
Biotechnology-based gene switching is the use of genetic engineering to control specific genes in plants to achieve desired results. These targeted genes are controlled through “switch mechanisms” which activate, deactivate, or adjust upward or downward gene functions. It is also described as controlling the “expression” of genes. Gene switching mechanisms are established either in response to an external trigger, to activate the genes at critical times, or in particular locations in the plant. It should be called “biotechnology-based gene switching” as gene switching occurs naturally and without human intervention. Researches have focused on gene switching applications to control genes related to specific plant traits. In these cases, all the other genes in the plant continue to function normally. Seeds from these plants could be saved by farmers and planted the next year, however, it often results in a crop without the special trait.
The biotechnology-based gene switching applications also include controlling genes for reproduction or seed germination. It controls plant reproduction either by limiting pollen production or by producing non-viable seeds. Examples of this are seedless grapes and watermelons.
What is the need to explore gene switching?
Researchers are exploring the use of gene switching to allow plants to express a gene only when it is needed. For instance, a drought tolerant plant will produce the gene for drought tolerance only when drought occurs. Other examples include the following:
- Sentinel plants that would notify farmers when there is a nutrient deficiency or a pest infestation in their fields
- Targeted release of Bt or other pest protection mechanisms within a plant, helping to further reduce the potential development of pest resistance
- The development of sterile progeny, further contributing to environmental risk management processes in centers of origin and other sensitive environments
National biosafety frameworks regulate viable products of genetic engineering, including any plants and organisms that may be created through gene switching technologies, on a case-by-case basis through scientific risk assessment. Accordingly, any unique attributes of products of gene switching, including those that result in sterile seed, automatically are considered in risk assessment and decision-making. Based on the Cartagena Protocol on Biosafety, gene switching products are continued to be regulated under the same biosafety system as any other biotechnology application.
What is the purpose of producing sterile seeds?
GURTs produce genetically engineered plants that cannot develop viable seeds, thus preventing unintended introduction to the environment. A number of government bodies have recognized this potential biosafety benefit of GURTs, and funds have been allocated to support additional research.
Companies produce sterile seeds to protect its technology and investment through preventing unauthorized saving of seeds for subsequent years. The farmer who purchases this seed will know that he will not be able to save seeds because these will be labelled by manufacturers with information on restrictions related to patents. However, GURTs products may cost more than conventional seeds. Some farmers still choose to buy these seeds because of particular benefits they offer.
Biotechnology-based gene switching in plants describes a wide range of mechanisms to control gene expression for purposes beneficial to human beings and the environment. These technologies hold promise to more efficient and effective traits in plants. The technology also offers an additional layer of biosafety protection as well as serving to protect research and development investments. All genetically modified organisms created through biotechnology-based gene switching can and should be reviewed and assessed on a case by case basis, under scientifically sound regulatory frameworks, in line with existing CBD guidance.
CGIAR. 1998. CGIAR International Centers Week. http://www.worldbank. org/html/cgiar/publications/icw98/icw98sop.pdf.
Ministry for the Environment. 2001. Royal Commission on Genetic Modification Report. http://www.mfe.govt.nz/sites/default/files/Royal%20Commission%20on%20GM%20in%20NZ.pdf.
About Author / Additional Info:
I am PhD research scholar, pursuing PhD at IARI, New Delhi in the discipline of Molecular Biology and Biotechnology. I am working on blast disease resistance in O. sativa