Determination of complex type free, non‐conjugated oligosaccharide glucose unit values in tomato xylem sap for early detection of nutrient deficiency

Although knowledge on glycan biosynthesis and processing is continuously maturing, there are still a limited number of studies that examine biological functions of N‐glycan structures in plants, which remain virtually unknown. Here, the statistical correlation between nutrient (nitrogen) deficiency symptoms of crops and changes in 8‐aminopyrene‐1,3,6‐trisulfonic acid (APTS)‐labeled complex type free oligosaccharides is reported. While deficiency symptoms are predicted by multispectral images and Kjeldahl digestion, APTS‐labeled complex type free oligosaccharides are identified by their glucose unit (GU) values in tomato xylem sap, using capillary electrophoresis with laser induced fluorescence detection (CE‐LIF). Given the limited number of structures obtained from plants, archived in the literature, in the future, it is intended to create an open access database of promising indicators, namely, glycan structures that are presumably responsible for the nutrient deficiency caused stress in plants (http://glycoplants.org).