Addressing Challenges to Enhance the Bioactives of Withania somnifera through Organ, Tissue, and Cell Culture Based Approaches

Abstract

Withania somnifera is a highly valued medicinal plant in traditional home medicine and is known for a wide range of bioactivities. Its commercial cultivation is adversely affected by poor seed viability and germination. Infestation by various pests and pathogens, survival under unfavourable environmental conditions, narrow genetic base, and meager information regarding biosynthesis of secondary metabolites are some of the other existing challenges in the crop. Biotechnological interventions through organ, tissue, and cell culture provide promising options for addressing some of these issues. In vitro propagation facilitates conservation and sustainable utilization of the existing germplasms and broadening the genetic base. It would also provide means for efficient and rapid mass propagation of elite chemotypes and generating uniform plant material round the year for experimentation and industrial applications. The potential of in vitro cell/organ cultures for the production of therapeutically valuable compounds and their large-scale production in bioreactors has received significant attention in recent years. In vitro culture system further provides distinct advantage for studying various cellular and molecular processes leading to secondary metabolite accumulation and their regulation. Engineering plants through genetic transformation and development of hairy root culture system are powerful strategies for modulation of secondary metabolites. The present review highlights the developments and sketches current scenario in this field.

Figure 1

Micropropagation of W. somnifera. (a) Initiation of aseptic cultures from seeds; (b) nodal explants in MS basal medium; (c) shoots growing in BAP (5 µM); (d) shoot proliferation; (e) rooted microshoots in IBA (10 µM); (f) hardened plant.

Figure 2

Regeneration from W. somnifera leaf explants. (a) Leaf explant from in vitro shoots; (b) initiation of callus formation in BAP (15 µM); (c) shoot bud formation in the same medium; (d) shoot buds observed under stereomicroscope; (e) emergence of shoots in BAP (5 µM); (f) proliferation of shoots in BAP (5 µM); (g) rooting of microshoots in IBA (10 µM); (h) hardening of microshoots.