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.