title: Dynamics of withanolide biosynthesis in relation to temporal expression pattern of metabolic genes in Withania somnifera (L.) Dunal: a comparative study in two morpho-chemovariants.
abstract: Withania somnifera (L.) Dunal synthesizes large array of pharmacologically active secondary metabolites known as withanolides. It has been extensively investigated in terms of chemistry and bioactivity profiling. However, there exists fragmentary information about the dynamics of withanolide biosynthesis at different phenophases in concert with the expression analysis of key pathway genes. In the present study, two morpho-chemovariants of W. somnifera were harvested at five developmental stages, dissected into leaf and root tissues and assayed for three major withanolides viz. withanolide-A (WS-1), withanone (WS-2) and withaferin A (WS-3) content using high performance liquid chromatography. The present investigation also analyzed the expression pattern of five withanolide biosynthetic pathway genes namely squalene synthase, squalene epoxidase, cycloartenol synthase, cytochrome P450 reductase 1, cytochrome P450 reductase 2 to corroborate with the metabolite flux at different developmental stages. The relative transcript profiles of identified genes at various ontogenetic stages illustrated significant variation in leaf and root tissues and were largely concurrent with the alteration in withanolide pool. Comparatively, the concentrations of withanolide A, withanone and withaferin A along with expression levels of all the five genes were appreciably higher in the leaves than in roots. Relative dynamics in terms of quantitative and qualitative profiles of withanolides in leaf and root tissues revealed least correspondence between the pattern of accumulation, possibly indicting towards de novo tissue-specific biosynthesis.
authors.affiliation: Plant Biotechnology, Indian Institute of Integrative Medicine (CSIR), Canal Road, Jammu, 180001, India.
authors.forename: Niha
authors.initials: N
authors.lastname: Dhar
authors.forename: Satiander
authors.initials: S
authors.lastname: Rana
authors.forename: Wajid Waheed
authors.initials: WW
authors.lastname: Bhat
authors.forename: Sumeer
authors.initials: S
authors.lastname: Razdan
authors.forename: Shahzad A
authors.initials: SA
authors.lastname: Pandith
authors.forename: Shabnam
authors.initials: S
authors.lastname: Khan
authors.forename: Prabhu
authors.initials: P
authors.lastname: Dutt
authors.forename: Rekha S
authors.initials: RS
authors.lastname: Dhar
authors.forename: Samantha
authors.initials: S
authors.lastname: Vaishnavi
authors.forename: Ram
authors.initials: R
authors.lastname: Vishwakarma
authors.forename: Surrinder K
authors.initials: SK
authors.lastname: Lattoo
mesh_terms: D053898:Biosynthetic Pathways / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D010641:Phenotype; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D013997:Time Factors; D032341:Withania / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D054358:Withanolides / Q000737:chemistry / Q000378:metabolism*
chemical_list: D054358:Withanolides