A critical evaluation of whether recombination in virus‐resistant transgenic plants will lead to the emergence of novel viral diseases

Abstract

Summary In the evaluation of the potential impacts of first‐generation genetically modified (GM) crops, one of the most complex issues has been whether the expression of viral sequences would lead to the emergence of novel viruses, which could occur through recombination between transgene mRNA and that of an infecting non‐target virus. Here, we examine this issue, focusing on Cucumber mosaic virus (CMV), which is a particularly pertinent choice, as it is both a major plant pathogen and also the virus with which this question has been studied in the most detail. Using recent results on recombination in CMV, we employ a novel framework giving particular prominence to the formulation of the risk hypothesis and to hypothesis testing via examination of the potential pathway to harm. This allows us to conclude with greater certainty that the likelihood of this potential harm, the emergence of novel viruses, is low.

Metagenomic‐based impact study of transgenic grapevine rootstock on its associated virome and soil bacteriome

“…Furthermore, as for bacteria, no HGT events between the F13‐cp transgene sequence and GFLV populations were identified, while a large number of natural recombination events were readily detected in silico and in vivo , confirming previous studies (Vigne et al ., 2004a, ). When added to previous investigations (Tepfer et al ., ), these findings, using state of the art high‐throughput sequencing technology, confirm that GM grapevine did not result in the emergence of novel recombinant viral isolates. Nonetheless, the GM grapevine line investigated in this study impacted the GFLV population diversity.…”

Assessment of unanticipated unintended effects of genetically modified plants on non‐target organisms: a controversy worthy of pursuit?

“…This process also requires the development of a conceptual model and an analysis plan, which helps to direct the risk characterization. Problem formulation contributes to maximize the usefulness of risk assessment studies for regulatory decision-making, as it enables a structured, logical approach to identifying harmful effects requiring characterization, while excluding non-harmful effects as irrelevant (Raybould 2006(Raybould , 2007(Raybould , 2010(Raybould , 2011Nickson 2008;Wolt et al 2010;Gray 2012;Tepfer et al 2015).…”

Towards plant resistance to viruses using protein-only RNase P

“…Another issue of pathogen-derived resistance strategies is the fact that plants genetically engineered for viral resistance encode parts of viral genomes. The risk of interactions between the transgene and the challenging virus-which may cause the appearance of more virulent strains through recombination or trans-encapsidation, is thus a concern for biosafety, human health, or environmental impact 22 . Such a risk is not expected with the CytoRP technology, as it does not depend on the insertion of pathogen-derived sequences into the plant genome.…”