Nuclear Magnetic Resonance Characterizes Metabolic Differences in Cymbopogon Schoenanthus Subsp. Proximus Embryogenic and Organogenic Calli and their Regenerated Shoots

Cymbopogon schoenanthus subsp. proximus is a threatened wild grass well known for its folk medicine uses and possesses a broad spectrum of pharmacological properties. In this study, the metabolite differences between embryogenic and organogenic calli have been characterized. Changes in the metabolome of somatic embryogenesis and organogenesis have been studied by comparing the metabolites of morphogenic calli with their respective regenerated shoots. Based on 1 H and HSQC NMR data of the polar extracts, a total of 51 metabolites have been identified. Statistical analyses were performed to visualize the pattern of metabolites distribution among the studied groups. Glycolate present in organogenic calli, but not in organogenic calli. Some metabolites like glucose-6-phosphate, 4-aminobutyrate and arginine showed elevated concentrations in embryogenic calli than organogenic calli. While sucrose and myo-inositol up regulated in organogenic calli than embryogenic calli. Metabolites that marked embryogenic shoots from embryogenic calli have been described. Quantitatively, embryogenic shoots showed higher concentrations of sucrose, some amino acids, and trigonelline compared with embryogenic calli. In contrast, glucose, fructose, and arginine accumulated in embryogenic calli more than in embryogenic shoots. Likewise, metabolites characterized organogenic shoots from organogenic calli have been identified. Sucrose, several amino acids and trigonelline were detected in higher concentrations in organogenic shoots than in organogenic calli while monosaccharides and arginine accumulated in organogenic calli than in organogenic shoots. This study represents a first step towards understanding the metabolic activity of calli and shoots regenerated through different morphogenetic pathways.