Overexpression of squalene synthase in Withania somnifera leads to enhanced withanolide biosynthesis

Singh

et al. 2018

Sci Rep

Tissue specific biosynthesis of secondary metabolites is a distinguished feature of medicinal plants. Withania somnifera, source of pharmaceutically important withanolides biosynthesizes withaferin-A in leaves and withanolide-A in roots. To increase the in planta withanolides production, a sustainable approach needs to be explored. Here, we isolated endophytes from different parts of W. somnifera plants and their promising role in in planta withanolide biosynthesis was established in both in-vivo grown as well in in-vitro raised composite W. somnifera plants. Overall, the fungal endophytes improved photosynthesis, plant growth and biomass, and the root-associated bacterial endophytes enhanced the withanolide content in both in-vivo and in-vitro grown plants by modulating the expression of withanolide biosynthesis genes in leaves and roots. Surprisingly, a few indole-3-acetic acid (IAA)-producing and nitrogen-fixing root-associated endophytes could induce the biosynthesis of withaferin-A in roots by inducing in planta IAA-production and upregulating the expression of withanolide biosynthesis genes especially MEP-pathway genes (DXS and DXR) in roots as well. Results indicate the role of endophytes in modulating the synthesis and site of withanolides production and the selected endophytes can be used for enhancing the in planta withanolide production and enriching roots with pharmaceutically important withaferin-A which is generally absent in roots.

Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Endophytes of Withania somnifera modulate in planta content and the site of withanolide biosynthesis

Singh

et al. 2018

Sci Rep

“…; Patel et al . ). HMGR of the MVA pathway and DXS , DXR of the MEP pathway both lead to Isopentenyl pyrophosphate (IPP) and Dimethylallyl pyrophosphate (DMAPP) which act as precursors for withanolide synthesis.…”

Section: Discussionmentioning

confidence: 97%

“…6) (Chaurasiya et al 2012). In recent years, many attempts have been made to clone and characterize some key genes encoding the enzymes involved in withanolide biosynthesis (Bhat et al 2012;Chaturvedi et al 2012;Rana et al 2013;Razdan et al 2013;Singh et al 2014;Patel et al 2015). HMGR of the MVA pathway and DXS, DXR of the MEP pathway both lead to Isopentenyl pyrophosphate (IPP) and Dimethylallyl pyrophosphate (DMAPP) which act as precursors for withanolide synthesis.…”

Section: Discussionmentioning

confidence: 99%

Leaf spot disease adversely affects human health-promoting constituents and withanolide biosynthesis inWithania somnifera(L.) Dunal

Singh

Sharma

et al. 2016

J Appl Microbiol

“…The protocol (Patel et al, 2014 ) used to overexpress of WsSQS in W. somnifera (Patel et al, 2015 ). Grover et al ( 2013 ) also transformed leaves and shoots of 4-6-weeks old seedlings with A. tumefaciens (GV3101 harboring pBI121H) containing SQS from W. somnifera .…”

Section: Accumulation Of Withanolides In Different Types Of mentioning

confidence: 99%

Withania somnifera: Advances and Implementation of Molecular and Tissue Culture Techniques to Enhance Its Application

et al. 2017

Withania somnifera, commonly known as Ashwagandha an important medicinal plant largely used in Ayurvedic and indigenous medicine for over 3,000 years. Being a medicinal plant, dried powder, crude extract as well as purified metabolies of the plant has shown promising therapeutic properties. Withanolides are the principal metabolites, responsible for the medicinal properties of the plant. Availability and amount of particular withanolides differ with tissue type and chemotype and its importance leads to identification characterization of several genes/ enzymes related to withanolide biosynthetic pathway. The modulation in withanolides can be achieved by controlling the environmental conditions like, different tissue culture techniques, altered media compositions, use of elicitors, etc. Among all the in vitro techniques, hairy root culture proved its importance at industrial scale, which also gets benefits due to more accumulation (amount and number) of withanolides in roots tissues of W. somnifera. Use of media compostion and elicitors further enhances the amount of withanolides in hairy roots. Another important modern day technique used for accumulation of desired secondary metabolites is modulating the gene expression by altering environmental conditions (use of different media composition, elicitors, etc.) or through genetic enginnering. Knowing the significance of the gene and the key enzymatic step of the pathway, modulation in withanolide contents can be achieved upto required amount in therapeutic industry. To accomplish maximum productivity through genetic enginnering different means of Withania transformation methods have been developed to obtain maximum transformation efficiency. These standardized transformation procedues have been used to overexpress/silence desired gene in W. somnifera to understand the outcome and succeed with enhanced metabolic production for the ultimate benefit of human race.