Indirect shoot regeneration from root explants, assessment of clonal fidelity of regenerated plants using SCoT primers and antioxidant analysis in Thottea siliquosa (Lamk.) Ding Hou

An efficient shoot regeneration protocol has been developed for Thottea siliquosa (Lamk.) Ding Hou. via indirect shoot regeneration from root explants. Roots were collected from 45-day-old in vitro rooted shoots and cultured on Murashige and Skoog (MS) medium supplemented with various plant growth regulators for callus induction. Optimum callus induction (93%) was observed on 3.0 mg/l Kinetin (KN) and 1.0 mg/l 2, 4-Dichlorophenoxyacetic acid (2, 4- D). The highest shoot induction response from calli was obtained on 0.5 mg/l N6-Benzyladenine (BA) and 0.2 mg/l & alpha;-Naphthaleneacetic (NAA). Here, 100% of cultures responded with a mean number of 20.3 shoots per unit calli. The best rooting (90% induction with 20.8 roots per shoot) of shoots was obtained on half-strength MS medium supplemented with 1.0 mg/l Indole-3-butyric acid (IBA). The rooted shoots were acclimatized and transferred to the field with 92% success. The prolonged subculture of calli resulted in its decreased regeneration potential. The clonal fidelity of regenerated plants and mother plants analyzed by Start Codon Targeted (SCoT) primers revealed the genetic similarity between them. The field established in vitro propagated plants showed higher total polyphenol and flavonoid content and total antioxidant capacity than the field grown mother plant and root derived callus. The DPPH radicle scavenging activity showed higher antioxidant activity in field grown plants than the in vitro cultured plants. The in vitro regeneration protocol developed here will be utilized for the mass multiplication and genetic transformation of this medicinal plant. Key messageAn efficient micropropagation protocol via root derived callus mediated shoot organogenesis was developed for Thottea siliquosa. The comparison of phytochemicals and antioxidant activity of callus, roots of in vitro and mother plants was studied.