Safety assessment principles for evaluation of crops in which level of expression of a particular gene has been specifically modulated by RNA interference or by alteration of relevant regulatory protein level.

Citation:

Parrott W, Chassy B, Ligon J, Meyer L, Petrick J, Zhou J, Herman R, Delaney B, Levine M. (2010) Application of food and feed safety assessment principles to evaluate transgenic approaches to gene modulation in crops. Food Chem Toxicol. 2010 Jul;48(7):1773-90. Epub 2010 Apr 23. PMID: 20399824

Content Summary

This review paper provides an historical overview of the principles that are needed for making a safety assessment of genetically modified crops, and an indication of where these need to be modified in light of modern knowledge. For example it considers the issues that are raised about the effects of insertion of new DNA and creation of novel genes during genetic manipulation in light of finding that this occurs frequently during plant domestication and traditional breeding without any recognised safety implications. It goes on to examine safety assessment of new plants when they are modified by technique that modulate the way in which existing plant genes are expressed, as opposed to introduction of a transgene from another species. Such modulation of the way in which existing genes are expressed can be achieved by RNA interference methods or all manipulation of plant proteins involved in gene regulation. These methods are likely to be used for usefully modifying plant composition or for conferring traits like improved resistance to water stress.

Abstract

New crop varieties containing traits such as enhanced nutritional profiles, increased yield, and tolerance to drought are being developed. In some cases, these new traits are dependent on small RNAs or regulatory proteins such as transcription factors (TF) that modify the expression of endogenous plant genes. To date, the food and feed safety of genetically modified (GM) crops has been assessed by the application of a set of internationally accepted procedures for evaluating the safety of GM crops. The goal of this paper is to review the main aspects of the current safety assessment paradigm and to recommend scientifically sound principles for conducting a safety assessment for GM crops that are developed by technologies that modify endogenous plant gene expression. Key considerations for such a safety assessment include the following: (1) RNA and TF are generally recognized as safe (GRAS); (2) Genes encoding RNAi and regulatory proteins such as TFs are an important component of the plantgenome; (3) Crops engineered using RNAi modifications are not expected to produce heterologous proteins; (4) The modulation of TFs may result in quantitative differences in endogenous plant components,which can be assessed through agronomic performance and compositional analysis on a caseby-case basis.