Callusing and untargeted metabolic profiling in Red sanders var. MTP 1

Red Sanders (Pterocarpus santalinus L.) is an economically important forest tree crop that is endangered and endemic to the Indian Sub-Continent. Red Sanders (Pterocarpus santalinus L.) is one of the most sought-after timber trees (listed in the IUCN red list) in the international market for its brick / blood red heartwood and is vulnerable to illegal felling and trading. To conserve Red Sanders and prevent its extinction, preserving its germplasm is crucial. Developing a micropropagation protocol is also essential to mass-produce elite genotypes for the timber industry. This study aims to establish a micropropagation method through callus induction using shoot tip explants. Further, the study identified that in tissue culture studies using shoot tip explants, we identified that 5 % CaOCl2 is the best for controlling both epiphytic and endophytic microbes. For callus induction, MS medium modified with different concentrations of TDZ viz., 1, 3 and 5 ppm was used. Explants were surface sterilized with 5 % CaOCl2 and inoculated in the MS + TDZ media under complete dark conditions. The calli could be potentially used for indirect organogenesis, somatic embryogenesis as well as suspension cultures. Hence, it is concluded that 1 % TDZ was an effective callus inducer. Comparative GC-MS analyses of in vivo grown shoot tips and in vitro grown calli identified 290 metabolites in all the samples tested. Detailed metabolomic analyses will shed light on the molecular biology and biochemistry of callus induction pathways in future.