Accumulation patterns of phenylpropanoids and enzymes in East Indian sandalwood tree undergoing developmental progression in vitro

Abstract The East Indian Sandalwood tree, Santalum album L., is sought for its fragrant essential oil and heartwood. The prolonged harvestable economic phase, over-exploitation, and poaching have contributed to extensive micro propagation endeavors in this woody tropical species. However, till date there is no information available regarding the metabolic changes associated with its development in vitro. Established in vitro cultures (i.e. callus, somatic embryo, and somatic seedlings) were examined extensively for phenylpropanoid pathway enzymes and metabolite accumulation patterns. Two to twelve fold increases in critical enzymatic activities across the three stages suggested a progressive developmental organization. Phenylpropanoid analysis by reverse phasehigh performance liquid chromatography (RP-HPLC) and liquid chromatography-electro spray ionization-mass spectrometry (LC-ESI-MS/MS) revealed changes and distribution patterns of 18 phenolics and 46 phenylpropanoids, respectively. Moreover, anatomical studies yielded insights into the vasculature's progressive organization and enhanced complexity. This study constitutes the first ever report on a comprehensive phenylpropanoid profiling analysis in East Indian sandalwood tree