Rapid, reliable plantlet regeneration, hairy root induction and in vitro potential for solasodine alkaloid accumulation in an important medicinal plant Solanum virginianum

• Published in: Plant cell, tissue and organ culture tissue and organ culture, 2023-04, Vol.153 (1), p.191-204
• Main Authors: Dalavi, Charushila M., Naravula, Jalaja, Kavi Kishor, P. B., Patil, Swaroopa
• Format: Article
• Language: English
• Subjects: Accumulation; Alkaloids; Benzyladenine; Bioactive compounds; Biomedical and Life Sciences; Bioreactors; Chitosan; Explants; Hairy root; Herbal medicine; Leaves; Life Sciences; Medicinal plants; Metabolites; Original Article; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant Sciences; Plants (botany); Polymerase chain reaction; Propagation; Roots; Secondary metabolites; Shoots; Soil mixtures; Solanum; Stems; Steroids; Survival; Thidiazuron
• ISSN: 0167-6857; 1573-5044
• DOI: 10.1007/s11240-023-02459-w

Nodal explants of an important medicinal plant Solanum virginianum have been used in the present study for rapid, reliable and systematic in vitro propagation. Among different concentrations of 6-benzyladenine (BA), Murashige and Skoog’s (MS) medium containing 0.75 mg/l BA has been ideal with 95% response and 31.7 shoots/explant (p ˂ 0.05). Though 1 to 1.5 mg/l thidiazuron (TDZ) responded with 100% frequency, the number of shoots formed per explant was only ~ 2–3. On the other hand, 0.75 and 1 mg/l BA + TDZ cocktail resulted in the differentiation of an optimum of 64 shoots/explant with 90% frequency of response, inferring the ideal combination. Shoot buds/microshoots obtained on BA (0.75 mg/l) and TDZ (1 mg/l) combination when recultured on diverse concentrations of BA, microshoot multiplication was 100%, mean number of shoots formed 26/explant with an average shoot length of 4.43 cm. IBA (2.5 mg/l) plus IAA (1.5 mg/l) combination differentiated 27 roots/shoot with 92% frequency with a mean length of 6.25 cm. Whole plants regenerated were hardened on red soil: sand mixture (1:1) with 95% survival rate. Hairy roots were initiated from leaf and stem explants of S. virginianum and the gene insertion was ascertained by polymerase chain reaction (PCR) amplification. Solasodine (C 27 H 43 O 2 N), an important steroid alkaloid of this plant accumulated at levels of 21 µg/g dry weight in in vitro generated stems exposed to 300 mg/l chitosan when compared to control (15 µg). Solasodine accumulation was less in 50 mg/l chitosan-treated leaves of regenerated plants (4.4 µg) and also devoid of it (2 µg). Key message Interestingly, hairy roots accumulated 79 µg of solasodine when treated with 100 mg/l chitosan, which can be further exploited for commercial production in a bioreactor. Induction of hairy roots, thereafter production of secondary metabolites in Solanum has proved to be the best method for enhancement of steroidal alkaloids. Moreover, elicitation is an effective strategy for increased production of commercially important bioactive compounds from hairy roots which has been demonstrated in the present investigation.