In:
New Phytologist, Wiley, Vol. 215, No. 3 ( 2017-08), p. 1115-1131
Abstract:
Withania somnifera produces pharmacologically important triterpenoid withanolides that are derived via phytosterol pathway; however, their biosynthesis and regulation remain to be elucidated. A jasmonate‐ and salicin‐inducible WRKY transcription factor from W. somnifera ( Ws WRKY 1 ) exhibiting correlation with withaferin A accumulation was functionally characterized employing virus‐induced gene silencing and overexpression studies combined with transcript and metabolite analyses, and chromatin immunoprecipitation assay. Ws WRKY 1 silencing resulted in stunted plant growth, reduced transcripts of phytosterol pathway genes with corresponding reduction in phytosterols and withanolides in W. somnifera . Its overexpression elevated the biosynthesis of triterpenoids in W. somnifera (phytosterols and withanolides), as well as tobacco and tomato (phytosterols). Moreover, Ws WRKY 1 binds to W‐box sequences in promoters of W. somnifera genes encoding squalene synthase and squalene epoxidase, indicating its direct regulation of triterpenoid pathway. Furthermore, while Ws WRKY 1 silencing in W. somnifera compromised the tolerance to bacterial growth, fungal infection, and insect feeding, its overexpression in tobacco led to improved biotic stress tolerance. Together these findings demonstrate that Ws WRKY 1 has a positive regulatory role on phytosterol and withanolides biosynthesis, and defense against biotic stress, highlighting its importance as a metabolic engineering tool for simultaneous improvement of triterpenoid biosynthesis and plant defense.
Type of Medium:
Online Resource
ISSN:
0028-646X
,
1469-8137
DOI:
10.1111/nph.2017.215.issue-3
Language:
English
Publisher:
Wiley
Publication Date:
2017
detail.hit.zdb_id:
208885-X
detail.hit.zdb_id:
1472194-6
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