Glycomic Mapping of the Maize Plant Points to Greater Utilization of the Entire Plant

The goal of food
sustainability is possible if greater utilization
of plants is achieved. In corn, only the kernels are currently used
for human consumption; however, edible carbohydrates that may function
as dietary fiber are present throughout the plant. A glycomic map
of the maize plant was obtained providing a broad structural view
of the carbohydrate distribution revealing that non-cellulosic material
was present throughout. Newly developed rapid throughput liquid chromatography
tandem mass spectrometry-based methods for analyzing monosaccharide
and linkage compositions show unique structural features in the respective
segments and parts of the plants from the roots to the tassel. The
most abundant monosaccharides of the 14 that were monitored included
glucose, xylose, and arabinose. Additionally, galactose, fructose,
rhamnose, mannose, galacturonic acid, and glucuronic acid were found
in lower abundances. The relative abundances of each monosaccharide
varied with the parts of the plants. Linkage compositions also varied
and provided further structural information that included the presence
of polysaccharides such as xylans, starch, pectins, xyloglucans, arabinans,
galactans, and β-glucans. The nonstructural carbohydrate components
including the free mono- and disaccharides were also measured to provide
a unique geographical map of their abundances. The glycomic map of
corn would guide traditional plant breeding methods and new genome
editing tools toward tissue-specific enhancements of carbohydrate
polymers that have unique and specific functional utility.