沉香基因組體與關係葫蘆素等次級代謝物生合成路徑調控之研究

A draft genome for Aquilaria agallocha and a study of agarwood secondary metabolism with respect to cucurbitacin

陳筌鴻(Chuan-Hung Chen)

指導教授 ： 陳榮芳

共同指導教授 ： 鄭石通

國立臺灣大學/生命科學院/植物科學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.10471

摘要

在傳統亞洲宗教文化中，沉香有其特定需求與價值性。然而，沉香對於東亞人民的意義不僅於此，在醫藥上更有其價值性。其中，台灣更是東亞的主要消費國之一。近年來，由於沉香樹結香具有極大的經濟價值，其價格在人為炒作下，不斷創新高，此舉引起人類的濫伐，導致沉香樹已經被列為瀕臨絕種的植物。雖然目前有許多關於沉香樹的組織培養研究，但是關於其基因組體與轉錄組體的相關研究甚少。敝研究團隊在沉香組培苗發現到重要抗癌化合物，cucurbitacin E and I 。為了更加了解沉香 (Aquilaria agallocha）有用物質生合成機制 ，研究室利用次世代定序(Next Generation Sequencing ,NGS) 這項技術進行功能性基因之挖掘。根據流式細胞儀基因組大小估算結果，沉香的基因組大小約為 736Mb。另外，根據 whole genome ，transcriptome，small RNA sequencing，和 bisulfite sequencing資料，已經分析篩選數十個可能參與 cucurbitacins 生合成的基因與 small RNA，可供後續研究所用。

關鍵字

沉香 ； Aquilaria agallocha ； 葫蘆素 ； 中草藥 ； 萜類

並列摘要

Background
The resinous portions of Aquilaria plants, called agarwood, have long been used as medicine and incense. In Asia, agarwood is a kind of Chinese herbal medicine. Many terpene derivatives of agarwood are known to have medicinal value to humans, including compounds that have been shown to elicit sedative effects and exhibit anti-cancer properties. However, little is known about the genome, transcriptome, small RNA, DNA methylation pattern, and the biosynthetic pathways responsible for producing such secondary metabolites in agarwood.

Results
In this project, we present draft genome for Aquilaria agallocha and a putative regulation mechanism for cucurbitacin E and I, compounds with known medicinal value, from in vitro Aquilaria agallocha agarwood. DNA and RNA data are utilized to annotate many genes and protein functions in the draft genome. The expression changes for cucurbitacin E and I are shown to be consistent with known responses of A. agallocha to methyl jasmonate and light condition and a set of homologous genes related to cucurbitacin bio-synthesis is presented and validated through qRT-PCR.

Conclusions
This study is the first attempt to identify cucurbitacin E and I from in vitro agarwood , the first draft genome, small RNAs data, and DNA methylation pattern for any species of Aquilaria. The results of this study will aid in future investigations of secondary metabolite pathways in Aquilaria and other non-model medicinal plants.

並列關鍵字

Agarwood ； Aquilaria agallocha ； Cucurbitacin ； Chinese herbal medicine ； terpenoid

參考文獻

Chapter 1

3. Shaw D: Toxicological Risks of Chinese Herbs. Planta Med 2010, 76(17):2012-2018.

4. Chen HQ, Wei JH, Yang JS, Zhang Z, Yang Y, Gao ZH, Sui C, Gong B: Chemical Constituents of Agarwood Originating from the Endemic Genus Aquilaria Plants. Chem Biodivers 2012, 9(2):236-250.

5. Liu Y, Chen H, Yang Y, Zhang Z, Wei J, Meng H, Chen W, Feng J, Gan B, Chen X et al: Whole-tree agarwood-inducing technique: an efficient novel technique for producing high-quality agarwood in cultivated Aquilaria sinensis trees. Molecules 2013, 18(3):3086-3106.

6. Ueda J, Imamura L, Tezuka Y, Tran QL, Tsuda M, Kadota S: New sesquiterpene from Vietnamese agarwood and its induction effect on brain-derived neurotrophic factor mRNA expression in vitro. Bioorganic & Medicinal Chemistry 2006, 14(10):3571-3574.