WRKY1-mediated regulation of tryptophan decarboxylase in tryptamine generation for withanamide production in Withania somnifera (Ashwagandha)
Autor: | Jyoti Singh Jadaun, Amit Kumar Kushwaha, Lokesh Kumar Narnoliya, Rajender S. Sangwan, Neelam S. Sangwan, Smrati Mishra |
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Rok vydání: | 2020 |
Předmět: |
Models
Molecular 0106 biological sciences 0301 basic medicine Tryptamine Indoles Plant Science Withania Withania somnifera Disaccharides 01 natural sciences 03 medical and health sciences chemistry.chemical_compound Gene Expression Regulation Plant Gene expression Escherichia coli Cloning Molecular Promoter Regions Genetic Overproduction Phylogeny Plant Proteins Indole test chemistry.chemical_classification Aromatic L-amino acid decarboxylase Plants Medicinal biology Tryptophan General Medicine Plants Genetically Modified biology.organism_classification Tryptamines 030104 developmental biology Enzyme chemistry Biochemistry Aromatic-L-Amino-Acid Decarboxylases Agronomy and Crop Science Transcription Factors 010606 plant biology & botany |
Zdroj: | Plant Cell Reports. 39:1443-1465 |
ISSN: | 1432-203X 0721-7714 |
Popis: | WsWRKY1-mediated transcriptional modulation of Withania somnifera tryptophan decarboxylase gene (WsTDC) helps to regulate fruit-specific tryptamine generation for production of withanamides. Withania somnifera is a highly valued medicinal plant. Recent demonstration of novel indolyl metabolites called withanamides in its fruits (berries) prompted us to investigate its tryptophan decarboxylase (TDC), as tryptophan is invariably a precursor for indole moiety. TDC catalyzes conversion of tryptophan into tryptamine, and the catalytic reaction constitutes a committed metabolic step for synthesis of an array of indolyl metabolites. The TDC gene (WsTDC) was cloned from berries of the plant and expressed in E. coli. The recombinant enzyme was purified and characterized for its catalytic attributes. Catalytic and structural aspects of the enzyme indicated its regulatory/rate-limiting significance in generation of the indolyl metabolites. Novel tissue-wise and developmentally differential abundance of WsTDC transcripts reflected its preeminent role in withanamide biogenesis in the fruits. Transgenic lines overexpressing WsTDC gene showed accumulation of tryptamine at significantly higher levels, while lines silenced for WsTDC exhibited considerably depleted levels of tryptamine. Cloning and sequence analysis of promoter of WsTDC revealed the presence of W-box in it. Follow-up studies on isolation of WsWRKY1 transcription factor and its overexpression in W. somnifera revealed that WsTDC expression was substantially induced by WsWRKY1 resulting in overproduction of tryptamine. The study invokes a key role of TDC in regulating the indolyl secondary metabolites through enabling elevated flux/supply of tryptamine at multiple levels from gene expression to catalytic attributes overall coordinated by WsWRKY1. This is the first biochemical, molecular, structural, physiological and regulatory description of a fruit-functional TDC. |
Databáze: | OpenAIRE |
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