Department of Bio-Health Convergence, Kangwon National University, Chuncheon 24341, Republic of Korea.
Department of Forest Resources, College of Forest and Environmental Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea.
Int J Mol Sci. 2023 Mar 17;24(6):5769. doi: 10.3390/ijms24065769.
(Campanulaceae) is a perennial plant commonly known as the bonnet bellflower. This species is widely used in traditional medicine and is considered to have multiple medicinal properties. In this study, we found that shoots and roots of contained various types of free triterpenes (taraxerol, β-amyrin, α-amyrin, and friedelin) and triterpene acetates (taraxerol acetate, β-amyrin acetate, and α-amyrin acetate). The content of triterpenes and triterpene acetates by GC analysis was higher in the shoot than in the roots. To investigate the transcriptional activity of genes involved in triterpenes and triterpene acetate biosynthesis, we performed de novo transcriptome analysis of shoots and roots of by sequencing using the Illumina platform. A total of 39,523 representative transcripts were obtained. After functional annotation of the transcripts, the differential expression of genes involved in triterpene biosynthetic pathways was investigated. Generally, the transcriptional activity of unigenes in the upstream region (MVA and MEP pathway) of triterpene biosynthetic pathways was higher in shoots than in roots. Various triterpene synthases (2,3-oxidosqualene cyclase, OSC) participate to produce triterpene skeletons by the cyclization of 2,3-oxidosqualene. A total of fifteen contigs were obtained in annotated OSCs in the representative transcripts. Functional characterization of four OSC sequences by heterologous expression in yeast revealed that ClOSC1 was determined as taraxerol synthase, and ClOSC2 was a mixed-amyrin synthase producing α-amyrin and β-amyrin. Five putative contigs of triterpene acetyltransferases showed high homology to the lettuce triterpene acetyltransferases. Conclusively, this study provides the basis of molecular information, particularly for the biosynthesis of triterpenes and triterpene acetates in .
（桔梗科）是一种多年生植物，通常被称为风铃草。该物种在传统医学中被广泛应用，并被认为具有多种药用特性。在这项研究中，我们发现含有各种类型的游离三萜（蒲公英甾醇、β-香树脂醇、α-香树脂醇和无羁萜）和三萜乙酸酯（蒲公英甾醇乙酸酯、β-香树脂醇乙酸酯和α-香树脂醇乙酸酯）。GC 分析表明，地上部分的三萜和三萜乙酸酯含量高于根部。为了研究参与三萜和三萜乙酸酯生物合成的基因的转录活性，我们使用 Illumina 平台对地上部分和根部的进行了从头转录组分析。共获得了 39523 个代表性转录本。对转录本进行功能注释后，研究了参与三萜生物合成途径的基因的差异表达。一般来说，三萜生物合成途径上游区域（MVA 和 MEP 途径）基因的转录活性在地上部分高于根部。各种三萜合酶（2,3-氧化鲨烯环化酶，OSC）通过 2,3-氧化鲨烯的环化参与三萜骨架的生成。在代表性转录本中，共获得了 15 个注释的 OSC 中的拼接体。通过在酵母中异源表达对四个 OSC 序列的功能表征表明，ClOSC1 被确定为蒲公英甾醇合酶，ClOSC2 是一种混合的α-香树脂醇合酶，产生α-香树脂醇和β-香树脂醇。五个假定的三萜乙酰转移酶的拼接体与生菜三萜乙酰转移酶具有高度同源性。总之，本研究提供了分子信息的基础，特别是在风铃草三萜和三萜乙酸酯的生物合成方面。
