Unintended changes in transgenic maize cause no nontarget effects

Societal Impact Statement Genetic engineering is used to introduce new genes into plants to obtain crops with novel traits. However, the unintended effects of genetically engineered (GE) crops on nontarget organisms—such as beneficial insects—are a topic of much concern. We evaluate the potential unintended effects of pollen from three GE maize and seven commercialized conventional maize lines on the ladybird beetle Propylea japonica, by combining omics approaches with feeding assays. Our results suggest that unintended changes caused by genetic engineering in maize pollen may not lead to biologically relevant effects on P. japonica. Meanwhile our study provides a useful strategy to assess the biological impacts of genetic engineering on nontarget organisms. Summary The potential effects caused by the inserted traits in genetically engineered (GE) plants on nontarget organisms (NTOs) have been well assessed. However, whether the process of genetic engineering itself causes unintended changes that go beyond the natural variation of the crop and further poses any biological effects to NTOs is still under debate. Here, we evaluated the potential unintended effects of pollen from three GE maize and seven commercialized conventional maize lines on the NTO Propylea japonica by combining omics approaches with feeding assays. The results showed that genetic breeding indeed brought somewhat differences at both proteome and metabolome levels in maize pollen, although such differences were far more common in conventionally crossbred plants. Feeding experiments indicated that the changes in proteins and metabolites caused by genetic breeding did not lead to unintended effects on the NTOs that go beyond those measured for the conventional crossbred lines. Together, our results suggest that the differences detected by omics experiments may not cause any biological relevant effects on NTOs and the combination of omics approaches and NTOs feeding assays provide a valid approach to assess the biological relevance of compositional effects caused by genetic breeding.