Agronomic and phenotypic plant traits as indicators for environmental risks of genetically modified plants

BackgroundFor market approval of genetically modified plants (GMPs), the evaluation of agronomic and phenotypic plant traits is a standard requirement and part of the comparative assessment of the GMP and its conventional counterpart. This comparative assessment is a starting point for environmental risk assessment (ERA) and should inform all areas of risk. We scrutinize frequently used approaches to characterize GMPs in EU market applications and discuss their usefulness for drawing conclusions on risks related to the plant's ability to survive, persist or become invasive.ResultsOur analysis shows that the agronomic and phenotypic characterization of GMPs, although based on guidelines, is confined to plant traits and test designs that are relevant for the quality control and agronomic performance of genetically modified (GM) crops. We provide evidence of how methodological approaches frequently applied during the agronomic and phenotypic characterization of the GMP could be improved and complemented to better inform on potential phenotypic changes relevant to assessing environmental risks. These approaches refer to (i) the assessment of the survival of GM seeds and plants (e.g., volunteers); (ii) the consideration of environmental exposure and (iii) improved methodological approaches for the assessment of biotic and abiotic stress responses for GMPs.ConclusionsThe comparative assessment of agronomic and phenotypic plant traits currently does not provide suitable data to draw conclusions on environmental risks relating to the persistence and invasiveness of the GMP. Ecologically more realistic assessments should be part of the phenotypic characterization of GMPs and need guidance and decision criteria to be implemented in ERA. This is of considerable importance, as new genomic techniques are expected to increase the diversity and complexity of GM plants and traits, particularly stress tolerance, which may affect the survival of GMPs in the environment.