Induction of somatic embryogenesis and ectopic proliferation in Tecoma stans (L.) Juss. ex Kunth cell suspension culture

Abstract

Somatic embryogenesis is a developmental pathway where somatic cells of plants generate embryogenic cells that subsequently mature into somatic embryos under favorable conditions. This process is one of the most important in vitro techniques for plant propagation, with diverse practical implications. In this study, ectopic proliferation and somatic embryos from Tecoma stans (L.) Juss. ex Kunth cell cultures were induced by employing primary conditioning Murashige and Skoog medium supplemented with 1.0 mg L⁻¹ 2,4-dichlorophenoxyacetic acid. Subsequently, a secondary induction medium supplemented with a combination of 1.0 mg L⁻¹ 2,4-dichlorophenoxyacetic acid with various concentrations of 6-benzyladenine cytokinin (1 to 5 mg L⁻¹) was used to promote embryogenesis. The results revealed the successful formation of pre-embryonic and embryonic stages, including globular, heart, torpedo, and cotyledon stages within a 2-wk incubation period under the specified hormonal conditions, leading to subsequent development into the mature vegetative phase after an additional 4 wk. Significant embryo production (16 ± 2.0 torpedo stage embryos per 50 mL culture media) was observed in Murashige and Skoog medium enriched with 1.0 mg L⁻¹ 2,4-dichlorophenoxyacetic acid and 2.0 mg L⁻¹ 6-benzyladenine, surpassing the results observed with other concentrations (p-value < 0.0001). The generated somatic embryos can serve as a potential in vitro tool for the propagation, generation, and organogenesis of T. stans, contributing to its role as both an ornamental and medicinal plant. Moreover, the induction of somatic embryogenesis opens avenues for the potential production of T. stans bioactive secondary metabolites and diverse applications in biotechnology, biotransformation, and biocatalysis, particularly in the conversion of both exogenous and endogenous substrates, such as tecomine—the principal antidiabetic alkaloid in the leaf extract.