AUTHOR=Thorat Sachin Ashok , Kaniyassery Arya , Poojari Poornima , Rangel Melissa , Tantry Shashikala , Kiran Kodsara Ramachandra , Joshi Manjunath B. , Rai Padmalatha S. , Botha Anna-Maria , Muthusamy Annamalai 

TITLE=Differential Gene Expression and Withanolides Biosynthesis During in vitro and ex vitro Growth of Withania somnifera (L.) Dunal

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.917770

DOI=10.3389/fpls.2022.917770

ISSN=1664-462X

ABSTRACT=Ashwagandha (Withania Somnifera L. Dunal) is a medicinally important plant with withanolides as its major bioactive compounds, abundant in the roots and leaves. We examined the influence of plant growth regulators (PGRs) on direct organogenesis, adventitious root development, withanolide biosynthetic pathway gene expression, withanolide contents, and metabolites during vegetative, and reproductive growth phases under in vitro and ex vitro conditions. The highest shooting responses were observed with BAP (2.0 mgL-1) + KIN (1.5 mgL-1) supplementation. Furthermore, BAP (2.0 mgL-1) + KIN (1.5 mgL-1) + GA3 (0.5 mgL-1) exhibited better elongation responses with in vitro flowering. Half-strength MS medium with IBA (1.5 mgL-1) exhibited the highest rooting responses and IBA (1.0 mgL-1) with highest fruits, and overall biomass. Higher contents of withaferin A (WFA) (~8.2 mgg-1 DW) were detected in reproductive phase, whereas substantially lower WFA contents (~1.10 mgg-1 DW) were detected in vegetative phase. CAS (P = 0.0025), SMT (P = 0.0059), and DXR (P = 0.0375) genes resulted in a significant fold change in expression during reproductive phase. The LC-MS analysis revealed metabolites that were common (177) and distinct in reproductive (218) and vegetative (167) phases. Adventitious roots cultured using varying concentrations of IAA (0.5 mgL-1) + IBA (1.0 mgL-1) + GA3 (0.2 mgL-1) exhibited highest biomass, and IAA (0.5 mgL-1) + IBA (1.0 mgL-1) exhibited highest withanolides content. Overall, our findings demonstrate the peculiarity of withanolide biosynthesis during distinct growth phases, which is relevant for large-scale production of withanolides.