Cloning and characterization of a tyrosine decarboxylase involved in the biosynthesis of galanthamine in Lycoris aurea

PeerJ

article

Rong Wang¹  Xiaokang Han¹  Sheng Xu¹  Bing Xia¹  Yumei Jiang¹  Yong Xue²  Ren Wang¹ 

[1] Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences;Eco-environmental Protection Research Institute, Shanghai Environmental Protection Monitoring Station of Agriculture, Shanghai Engineering Research Centre of Low-carbon Agriculture ,(SERLA), Shanghai Key Laboratory of Protected Horticultural Technology, Shanghai Academy of Agricultural Sciences

关键词: Tyrosine decarboxylase;    Amarylidaceae alkaloids;    Lycoris aurea;    Galanthamine;   

DOI  :  10.7717/peerj.6729

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

BackgroundGalanthamine, one kind of Amaryllidaceae alkaloid extracted from the Lycoris species, is used in the treatment of Alzheimer’s disease. In regards to medical and economic importance, the biosynthesis and regulatory mechanism of the secondary metabolites in Lycoris remain uninvestigated.MethodsBLAST was used to identify the sequence of tyrosine decarboxylase in the transcriptome of Lycoris aurea (L’Hér) Herb. The enzyme activity of this TYDC was determined by using heterologous expressed protein in the Escherichia coli cells. The related productive contents of tyramine were detected using High Performance Liquid Chromatography (HPLC). According to the available micro RNA sequencing profiles and degradome database of L. aurea, microRNA396 were isolated, which targets to LaTYDC1 and RNA Ligase-Mediated-Rapid Amplification of cDNA Ends (RLM-RACE) were used to confirm the cleavage. The expression levels of miR396 and LaTYDC1 were measured using a quantitative real-time polymerase chain reaction (qRT-PCR).ResultsLaTYDC1 was mainly expressed in root, bulb, leaf and flower fitting the models for galanthamine accumulation. This decarboxylase efficiently catalyzes tyrosine to tyramine conversion. Under methyl jasmonate (MeJA) treatment, the expression of LaTYDC1 and the content of tyramine sharply increase. The use of RLM-RACE confirms that miR396 promotes the degradation of LaTYDC1 mRNA. Under MeJA treatment, the expression of miR396 was suppressed while the expression level of LaTYDC1 sharply increased. Following the increase of the miR396 transcriptional level, LaTYDC1 was significantly repressed.ConclusionLaTYDC1 participates in the biosynthesis of galanthamine, and is regulated by miR396. This finding also provides genetic strategy for improving the yield of galanthamine in the future.

【 授权许可】

CC BY