Biotechnology Bulletin ›› 2025, Vol. 41 ›› Issue (2): 295-308.doi: 10.13560/j.cnki.biotech.bull.1985.2024-0760

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Functional Identification and Expression Analysis of Cinnamonyl Alcohol Dehydrogenase AsCAD in Angelica sinensis

XIANG Chun-fan1,2(), LI Le-song1,2, WANG Juan1,2, LIANG Yan-li1, YANG Sheng-chao1,2, LI Meng-fei3, ZHAO Yan1,2()   

  1. 1.Yunnan Agricultural University, National-Local Joint Engineering Research Center on Gemplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology, College of Agronomy and Biotechnology, Kunming 650201
    2.Yunnan Characteristic Plant Extraction Laboratory, Kunming 650106
    3.Agronomy College, Gansu Agricultural University, Lanzhou 730070
  • Received:2024-08-08 Online:2025-02-26 Published:2025-02-28
  • Contact: ZHAO Yan E-mail:17869407534@163.com;zhaoyankm@126.com

Abstract:

Objective The study is to explore the catalytic activity and expression characteristics of cinnamyl alcohol dehydrogenase, which is a key enzyme of lignin synthesis in Angelica sinensis, and to provide a new research idea and theoretical basis for solving the issue of lignification in the roots of A. sinensis. Method Unbolted roots (UBP) and bolted roots (BP) were used as experimental materials to identify candidate cinnamyl alcohol dehydrogenase genes based on transcriptome data. The full-length CDS of AsCADs gene was cloned, the prokaryotic expression vector pET-28a-AsCADs was constructed, transferred into E. coli BL21 (DE3), and the recombinant protein expression was induced and enzyme activity was measured in vitro. The active CAD protein sequences were analyzed by bioinformatics. Real-time quantitative PCR was used to analyze the gene expression patterns of UBP and BP. Result A total of 30 AsCADs genes were identified, among which 3 cinnamyl alcohol dehydrogenase genes, AsCAD1, AsCAD4 and AsCAD24, were reported and cloned, all containing two Zn2+ binding sites and 1 NAD(H) coenzyme binding site. In vitro enzymatic assay revealed that AsCAD1 catalyzed the reduction of coniferaldehyde and cafferaldehyde to the corresponding alcohols, and AsCAD4 and AsCAD24 catalyzed the reduction of p-coumaraldehyde, coniferaldehyde, cafferaldehyde and sinapaldehyde to the corresponding alcohols. AsCAD1, AsCAD4 and AsCAD24 contained an open reading frame of 1 083 bp, encoded 360 amino acids, and theoretical isoelectric points (pI) of 6.1 and 5.52, of which AsCAD1 was a hydrophobic protein, AsCAD4 and AsCAD24 were hydrophilic proteins, none of which contained a transmembrane structure and signal peptide, and the subcellular localization were in cytoplasm. RT-qPCR results showed that the expression of AsCAD1 was high in UBP, while AsCAD4 and AsCAD24 was high in BP. Conclusion The gene of AsCAD1, AsCAD4 and AsCAD24 are successfully cloned. The proteins all have catalytic activity after prokaryotic expression, and their relative expression levels are different in UBP and BP.

Key words: Angelica sinensis, lignification, cinnamyl alcohol dehydrogenase, prokaryotic expression, enzyme activity in vitro, expression analysis