Proliferation and Metabolic Profiling of Cynanchum wilfordii Adventitious Roots Using Explants from Different Cultivation Methods.

Cynanchum wilfordii root is used in traditional herbal medicine owing to its various pharmacological activities. However, C. wilfordii roots are misused owing to their morphological similarities with C. auriculatum. Adventitious root (AR) culture can prevent such misuse, and the selection of plant materials is an important procedure for producing high-quality ARs. This study aimed to compare the proliferation and metabolic profiles of C. wilfordii ARs in two types of explants from different cultivation methods (either cultivated in open field (ECF) or cultivated on a heap of C. wilfordii (ECH)). After 4 weeks of culture, the proliferation rate and number and length of secondary ARs were determined, and 3/4 Murashige and Skoog (MS) salt medium, 4.92 µM indole-3-butyric acid (IBA), and 5% sucrose were suggested as the best proliferation conditions for ARs originating from both ECF and ECH. Through metabolic profiling, ARs from ECH were found to show higher accumulation patterns for flavonoids, polysaccharides, hydroxyacetophenones, aromatic amino acids, and mono-unsaturated fatty acids, which were ascribed to the activation of flavonoid biosynthesis, the phenylpropanoid pathway, and fatty acid desaturase, stimulated by abiotic stresses. In contrast, ARs from ECF had higher levels of TCA cycle intermediates, amino acids in the aspartate-glutamate pathway, and saturated and polyunsaturated fatty acids, indicating energy metabolism and plant development. Overall, the current study provided information on the optimal conditions for inducing C. wilfordii ARs with higher amounts of bioactive compounds.