Risk assessment for de-regulation of transgenic crops
Authors: Rohini Sreevathsa, Rhitu Rai and Prasanta K Dash
ICAR-National Research Centre on Plant Biotechnology, LBS Building,
PUSA, New Delhi-110012.
Transgenic technology has emerged as a potential tool for deciphering basic intricacies in plants as well as development of improved crop varieties. Scientists have been successful in understanding the deep seated molecular mechanisms underlying various biotic and abiotic stress responses in plants through this technology. It has been two decades since the first transgenic product was introduced in the market. Studies have clearly revealed that, the acreage of transgenic crops is increasing by the day. From the initial planting of 1.7 million hectares in 1996 to 179.7 million hectares in 2015, it has been a remarkable 100-fold increase (James, 2015). Thus, biotech crops can be considered as one of the technologies gaining popularity and acceptance at a fast rate. This technology has been gauged to play an important role in agricultural sustainability in terms of food and nutritional security. However controversies surrounding it seem to be never ending and require stringent policies to be undertaken by the regulatory authorities to assure human health and environment safety (Singh et al. 2014).
The major concerns of humanity in acceptance of the transgenic crops, mainly the food crops has been the toxicity, allergenicity, development of antibiotic resistance, gene flow, development of super weeds and insect resistance. Safety of human and animal community has emerged as paramount importance (Robinson, 1999). Among the environmentalists, transgene escape to its non-transgenic counterpart or wild relatives has aroused tremendous debates about the genetic diversity. Hence public acceptance of the transgenic crops and its incorporation in the food commodities is a primary and colossal task for the regulatory authorities of any country. Hence, it is imperative for both the scientists and the regulators to coherently work towards acceptance. The foremost concern of the regulator is the evidence provided by the scientists for 'substantial equivalence' of the transgenic to its non-transgenic counterpart. Therefore, preliminary in the pipeline would be selection of transgenic events that are normal both phenotypically and physiologically. A number of non-interactive procedures serve as means to ward off unintended effects in the events that could occur either due to the positional effect of the T-DNA integration or expression of the transgene. Proteomic and metabolomic profiling measuring the metabolic end products can be used as tools to invariably decide event selection. Any unintended effect can be easily identified by comparative proteomic profiling which also precisely identifies the protein that has resulted in producing the unintended effect.
Once clarity about substantial equivalence is obtained, the next step would be risk assessment in terms of stringent toxicity, allerginicity and pure protein studies which would lead the transgenic to the verge of de-regulation. This has been amply demonstrated in the Bt crops and the herbicide tolerant crops. However, risk assessment of transgenics developed by new engineering approaches like genome editing, RNAi for transgenics is still under debate. Framing risk assessment strategies is challenging in the case of RNAi transgenics due to the lack of protein expression. Based on the deliberations in this direction, focus needs to be emphasized mainly on the effect on off-targets and the non-targets. Though information about this would have been generated prior to the development of transgenics, stringent risk assessment is required based on the food chain components on a case by case basis. Hence the assessment will be directed to the specific consumer, based on the crop and trait. Standard operating procedures (SOPs) to check the off-target and non-target effects will therefore form a major criterion in risk assessment of transgenics developed through host delivered RNAi. Additionally, physical exposure of the dsRNA and its environmental persistence is equally important in case of transgenics. In this direction, the effect of the transgenic on the soil microflora in the vicinity of the plant would form a direct evidence along with lack of negative effect on the beneficial organisms.
The acceptance of transgenic crops, especially the food crops therefore largely depends on the proof that incorporation of the transgene will not result in unintended and harmful effects on human and animal health.
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2. Singh M, Aglawe S, Lamalakshmi D, Kousar, Behera, Verma SK. Biosafety Concerns and Regulatory Framework for Transgenics. Res. J. Agri. Fores. Sci. Vol. 2(3), 7-13, (2014).
3. James, C. Biotech crop highlights in 2105. Ithaca, NY: International Service for the Acquisition of Agri-biotech Applications. (2015).
About Author / Additional Info:
Senior Scientist, Plant Biotechnology.