Virus-Induced Silencing of Key Genes Leads to Differential Impact on Withanolide Biosynthesis in the Medicinal Plant, Withania somnifera

Withanolides are a collection of naturally occurring, pharmacologically active, secondary metabolites synthesized in the medicinally important plant, Withania somnifera. These bioactive molecules are C28-steroidal lactone triterpenoids and their synthesis is proposed to take place via the mevalonate (MVA) and 2-C-methyl-d-erythritol-4-phosphate (MEP) pathways through the sterol pathway using 24-methylene cholesterol as substrate flux. Although the phytochemical profiles as well as pharmaceutical activities of Withania extracts have been well studied, limited genomic information and difficult genetic transformation have been a major bottleneck towards understanding the participation of specific genes in withanolide biosynthesis. In this study, we used the Tobacco rattle virus (TRV)-mediated virus-induced gene silencing (VIGS) approach to study the participation of key genes from MVA, MEP and triterpenoid biosynthesis for their involvement in withanolide biosynthesis. TRV-infected W. somnifera plants displayed unique phenotypic characteristics and differential accumulation of total Chl as well as carotenoid content for each silenced gene suggesting a reduction in overall isoprenoid synthesis. Comprehensive expression analysis of putative genes of withanolide biosynthesis revealed transcriptional modulations conferring the presence of complex regulatory mechanisms leading to withanolide biosynthesis. In addition, silencing of genes exhibited modulated total and specific withanolide accumulation at different levels as compared with control plants. Comparative analysis also suggests a major role for the MVA pathway as compared with the MEP pathway in providing substrate flux for withanolide biosynthesis. These results demonstrate that transcriptional regulation of selected Withania genes of the triterpenoid biosynthetic pathway critically affects withanolide biosynthesis, providing new horizons to explore this process further, in planta.

Medienart:

E-Artikel

Erscheinungsjahr:

2018

Erschienen:

2018

Enthalten in:

Zur Gesamtaufnahme - volume:59

Enthalten in:

Plant & cell physiology - 59(2018), 2 vom: 01. Feb., Seite 262-274

Sprache:

Englisch

Beteiligte Personen:

Agarwal, Aditya Vikram [VerfasserIn]
Singh, Deeksha [VerfasserIn]
Dhar, Yogeshwar Vikram [VerfasserIn]
Michael, Rahul [VerfasserIn]
Gupta, Parul [VerfasserIn]
Chandra, Deepak [VerfasserIn]
Trivedi, Prabodh Kumar [VerfasserIn]

Links:

Volltext

Themen:

1406-65-1
36-88-4
7183-41-7
Carotenoids
Chlorophyll
Erythritol
Erythritol 4-phosphate
Journal Article
Mevalonic Acid
Plant Proteins
RA96B954X6
RNA, Messenger
S5UOB36OCZ
Sugar Phosphates
Withanolides

Anmerkungen:

Date Completed 30.08.2018

Date Revised 30.08.2018

published: Print

Citation Status MEDLINE

doi:

10.1093/pcp/pcx179

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM278317790