Metabolic changes in transgenic maize mature seeds over-expressing the Aspergillus niger phyA2
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Non-targeted metabolomics analysis revealed only intended metabolic changes in transgenic maize over-expressing the Aspergillus niger phyA2.
Genetically modified (GM) crops account for a large proportion of modern agriculture worldwide, raising increasingly the public concerns of safety. Generally, according to substantial equivalence principle, if a GM crop is demonstrated to be equivalently safe to its conventional species, it is supposed to be safe. In this study, taking the advantage of an established non-target metabolomic profiling platform based on the combination of UPLC-MS/MS with GC–MS, we compared the mature seed metabolic changes in transgenic maize over-expressing the Aspergillus niger phyA2 with its non-transgenic counterpart and other 14 conventional maize lines. In total, levels of nine out of identified 210 metabolites were significantly changed in transgenic maize as compared with its non-transgenic counterpart, and the number of significantly altered metabolites was reduced to only four when the natural variations were taken into consideration. Notably, those four metabolites were all associated with targeted engineering pathway. Our results indicated that although both intended and non-intended metabolic changes occurred in the mature seeds of this GM maize event, only intended metabolic pathway was found to be out of the range of the natural metabolic variation in the metabolome of the transgenic maize. Therefore, only when natural metabolic variation was taken into account, could non-targeted metabolomics provide reliable objective compositional substantial equivalence analysis on GM crops.
KeywordsGC–MS Phytase Safety assessment Transgenic Substantial equivalence UPLC-MS/MS
We thank Dr. Rumei Chen from China Academy of Agricultural Sciences for supplying the seeds of transgenic maize overexpressing Aspergillus niger phyA2 and its non-transgenic counterpart used in present study. We also thank Dr. Guorun Qu, Ms. Fang Cheng, Qian Luo, and Jing Zhou for their assistance in the metabolomic analysis. This work was supported by the China National Transgenic Plant Special Fund (2013ZX08012-002 and 2014ZX08012-002), and the Programme of Introducing Talents of Discipline to Universities (111 Project, B14016) to Dabing Zhang.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
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