Shan Chun-Miao, Wang Chen-Kai, Shi Yuan-Yuan, Zhang Sheng-Xiang, Zhao Li-Qiang, Wu Jia-Wen
Graduate School, Anhui University of Chinese Medicine Hefei 230012, China Key Laboratory of Xin'an Medicine,Ministry of Education, Experimental Center for Scientific Research, Anhui University of Chinese Medicine Hefei 230038, China.
Key Laboratory of Xin'an Medicine,Ministry of Education, Experimental Center for Scientific Research, Anhui University of Chinese Medicine Hefei 230038, China Anhui Academy of Chinese Medicine Hefei 230012, China Synergetic Innovation Center of Anhui Authentic Chinese Medicine Quality Improvement Hefei 230012, China.
Zhongguo Zhong Yao Za Zhi. 2020 Jun;45(12):2847-2857. doi: 10.19540/j.cnki.cjcmm.20200329.108.
Steroidal saponins, which are the characteristic and main active constituents of Polygonatum, exhibit a broad range of pharmacological functions, such as regulating blood sugar, preventing cardiovascular and cerebrovascular diseases and anti-tumor. In this study, we performed RNA sequencing(RNA-Seq) analysis for the flowers, leaves, roots, and rhizomes of Polygonatum cyrtonema using the BGISEQ-500 platform to understand the biosynthesis pathway of steroidal saponins and study their key enzyme genes. The assembly of transcripts for four tissues generated 129 989 unigenes, of which 88 958 were mapped to several public databases for functional annotation, 22 813 unigenes were assigned to 53 subcategories and 64 877 unigenes were annotated to 136 pathways in KEGG database. Furthermore, 502 unigenes involved in the biosynthesis pathway of steroidal saponins were identified, of which 97 unigenes encoding 12 key enzymes. Cycloartenol synthase, the first key enzyme in the pathway of phytosterol biosynthesis, showed conserved catalytic domain and substrate binding domain based on sequence analysis and homology modeling. Differentially expressed genes(DEGs) were identified in rhizomes as compared to other tissues(flowers, leaves or roots).The 2 437 unigenes annotated by KEGG showed rhizome-specific expression, of which 35 unigenes involved in the biosynthesis of steroidal saponins. Our results greatly extend the public transcriptome dataset of Polygonatum and provide valuable information for the identification of candidate genes involved in the biosynthesis of steroidal saponins and other important secondary metabolites.
甾体皂苷是黄精属植物的特征性和主要活性成分，具有广泛的药理功能，如调节血糖、预防心脑血管疾病和抗肿瘤。在本研究中，我们使用BGISEQ-500平台对多花黄精的花、叶、根和根茎进行了RNA测序（RNA-Seq）分析，以了解甾体皂苷的生物合成途径并研究其关键酶基因。四个组织的转录本组装产生了129989个单基因，其中88958个被映射到几个公共数据库进行功能注释，22813个单基因被分配到53个亚类，64877个单基因在KEGG数据库中被注释到136条途径。此外，鉴定出502个参与甾体皂苷生物合成途径的单基因，其中97个单基因编码12种关键酶。基于序列分析和同源建模，植物甾醇生物合成途径中的第一个关键酶环阿屯醇合酶显示出保守的催化结构域和底物结合结构域。与其他组织（花、叶或根）相比，在根茎中鉴定出差异表达基因（DEG）。KEGG注释的2437个单基因显示出根茎特异性表达，其中35个单基因参与甾体皂苷的生物合成。我们的结果极大地扩展了黄精属植物的公共转录组数据集，并为鉴定参与甾体皂苷和其他重要次生代谢物生物合成的候选基因提供了有价值的信息。
