Metabolite Profiling of Maize KernelsGenetic Modification versus Environmental Influence

A metabolite profiling approach based on gas chromatography–mass
spectrometry (GC-MS) was applied to investigate the metabolite profiles
of genetically modified (GM) Bt-maize (DKC78-15B, TXP 138F) and Roundup
Ready-maize (DKC78-35R). For the comparative investigation of the
impact of genetic modification versus environmental influence on the
metabolite profiles, GM maize was grown together with the non-GM near-isogenic
comparators under different environmental conditions, including several
growing locations and seasons in Germany and South Africa. Analyses
of variance (ANOVA) revealed significant differences between GM and
non-GM maize grown in Germany and South Africa. For the factor genotype,
4 and 3%, respectively, of the total number of peaks detected by GC-MS
showed statistically significant differences (p <
0.01) in peak heights as compared to the respective isogenic lines.
However, ANOVA for the factor environment (growing location, season)
revealed higher numbers of significant differences (p < 0.01) between the GM and the non-GM maize grown in Germany
(42%) and South Africa (10%), respectively. This indicates that the
majority of differences observed are related to natural variability
rather than to the genetic modifications. In addition, multivariate
data assessment by means of principal component analysis revealed
that environmental factors, that is, growing locations and seasons,
were dominant parameters driving the variability of the maize metabolite
profiles.