ORIGINAL ARTICLE Comprehensive assessment of the genes involved in withanolide biosynthesis from Withania somnifera: chemotype-specific and elicitor-responsive expression Aditya Vikram Agarwal 1,2 & Parul Gupta 1,3 & Deeksha Singh 1,4 & Yogeshwar Vikram Dhar 1,4 & Deepak Chandra 2 & Prabodh Kumar Trivedi 1,4 Received: 5 September 2016 /Revised: 19 December 2016 /Accepted: 30 January 2017 # Springer-Verlag Berlin Heidelberg 2017 Abstract Withania somnifera (L.) Dunal (Family, Solanaceae), is among the most valuable medicinal plants used in Ayurveda owing to its rich reservoir of pharmaceuti- cally active secondary metabolites known as withanolides. Withanolides are C 28 -steroidal lactones having a triterpenoidal metabolic origin synthesised via mevalonate (MVA) pathway and methyl-D-erythritol-4-phosphate (MEP) pathway involv- ing metabolic intermediacy of 24-methylene (C 30 -terpenoid) cholesterol. Phytochemical studies suggest differences in the content and/or nature of withanolides in different tissues of different chemotypes. Though development of genomic re- sources has provided information about putative genes encoding enzymes for biosynthesis of intermediate steps of terpenoid backbone, not much is known about their regulation and response to elicitation. In this study, we generated detailed molecular information about genes catalysing key regulatory steps of withanolide biosynthetic pathway. The full-length se- quences of genes encoding enzymes for intermediate steps of terpenoid backbone biosynthesis and their paralogs have been characterized for their functional and structural properties as well as phylogeny using bioinformatics approach. The expression analysis suggests that these genes are differen- tially expressed in different tissues (with maximal expres- sion in young leaf), chemotypes and in response to salicylic acid (SA) and methyl jasmonate (MJ) treatments. Sub- cellular localization studies suggest that both paralogs of sterol Δ-7 reductase (WsDWF5-1 and WsDWF5-2) are lo- calized in the endoplasmic reticulum (ER) thus supporting their indispensible role in withanolide biosynthesis. Comprehensive information developed, in this study, will lead to elucidation of chemotype- as well as tissue-specific withanolide biosynthesis and development of new tools for functional genomics in this important medicinal plant. Keywords Chemotypes . Elicitor response . Triterpenoid biosynthetic pathway . Sub-cellular localization . Withania somnifera . Withanolides Introduction Plant secondary metabolites (SMs) make up an important in- gredient of a wide range of commercial and industrial appli- cations like pharmaceuticals, agrochemicals, flavours, fra- grances, colours, biopesticides and food additives (Hussain et al. 2012). Biosynthesis and accumulation of these second- ary plant products is species- as well as chemotype-specific and under tight spatial and temporal regulation of gene expres- sion (Gupta et al. 2013a, 2015; Pathak et al. 2013), which limit their proper industrial utilization and drug development. Although biotechnological approaches have been successful in enhancing biosynthesis of few valuable secondary metabo- lites (Pandey et al. 2014, 2015; Zhang et al. 2015), these ap- proaches cannot be used for other diverse molecules due to Electronic supplementary material The online version of this article (doi:10.1007/s10142-017-0548-x) contains supplementary material, which is available to authorized users. * Prabodh Kumar Trivedi prabodht@nbri.res.in; prabodht@hotmail.com 1 Council of Scientific and Industrial Research, National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India 2 Department of Biochemistry, University of Lucknow, Lucknow 226007, India 3 Present address: Botany and Plant Pathology, Oregon State University, 2082-Cordley Hall, Corvallis, OR 97331, USA 4 Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India Funct Integr Genomics DOI 10.1007/s10142-017-0548-x