Micropropagation of Drypetes roxburghii (Wall.) Hurusawa—a valuable medicinal plant through root culture and evaluation of its genetic fidelity and metabolomics

Abstract

Drypetes roxburghii (Wall.) Hurusawa (Euphorbiaceae) is a valuable endemic medicinal plant. The International Union for Conservation of Nature Red Data Book classified it under threatened species. The seeds exhibit low viability, prolonged dormancy, and a low germination rate. In the current study, direct shoot regeneration from the root explant was achieved, which helps in the conservation of germplasm. Root explants were cultured on woody plant as well as Murashige and Skoog medium containing 6-benzylaminopurine (0.5–5.0 mg L−1), kinetin (0.5–5.0 mg L−1), meta-Topolin (0.5–5.0 mg L−1), thidiazuron (0.1–1.5 mg L−1), and N-(2-chloro-4-pyridyl)-N′-phenyl urea (0.1–1.0 mg L−1). The 2.0 mg L−1meta-Topolin supplemented in WP medium was found most effective for induction of maximum shoot responding frequency (100 ± 0.0), number of shoots/explant (6.47 ± 0.21), and mean shoot length (4.54 ± 0.19 cm). The direct shoot organogenesis was observed under scanning electron microphotographs. Similarly, histological observations confirmed its direct origin from pericycle tissues. The microshoots showed the best rooting on Murashige and Skoog media containing indole-3-butyric acid (3.0 mg L−1) with a maximum percent responding frequency (95 ± 2.89), numbers of roots/shoot (4.41 ± 0.06), and mean root length (6.10 ± 0.10 cm). Plants were well acclimatized and grown in the field. The genetic homogeneity among mother and micropropagated plants was established using inter-simple sequence repeat, start codon targeted markers, and DNA content (2C) analysis with the help of flow cytometry. Regenerated plants exhibited good antioxidant activity. Both plants showed similar metabolites based on Fourier transform infrared and high-resolution mass spectrometry analyses. This protocol can be used for conservation, multiplication, and genetic improvement by transforming the elite clones. © The Society for In Vitro Biology 2025.