Metabolomic Assessment of Key Maize Resources: GC-MS and NMR Profiling of Grain from B73 Hybrids of the Nested Association Mapping (NAM) Founders and of Geographically Diverse Landraces

The
present study expands metabolomic assessments of maize beyond
commercial lines to include two sets of hybrids used extensively in
the scientific community. One set included hybrids derived from the
nested association mapping (NAM) founder lines, a collection of 25
inbreds selected on the basis of genetic diversity and used to investigate
the genetic basis of complex plant traits. A second set included 24
hybrids derived from a collection of landraces representative of native
diversity from North and South America that may serve as a source
of new alleles for improving modern maize hybrids. Metabolomic analysis
of grain harvested from these hybrids utilized gas chromatography–time-of-flight
mass spectrometry (GC-TOF-MS) and 1H nuclear magnetic resonance
spectroscopy (1H NMR) techniques. Results highlighted extensive
metabolomic variation in grain from both hybrid sets, but also demonstrated
that, within each hybrid set, subpopulations could be differentiated
in a pattern consistent with the known genetic and compositional variation
of these lines. Correlation analysis did not indicate a strong association
of the metabolomic data with grain nutrient composition, although
some metabolites did show moderately strong correlations with agronomic
features such as plant and ear height. Overall, this study provides
insights into the extensive metabolomic diversity associated with
conventional maize germplasm.