基于比较转录组学的多花黄精黄酮类化合物合成基因表达分析

Analysis of Genes Expression Involved in Flavonoids Biosynthesis in Polygonatum cyrtonema Based on Comparative Transcriptome

为了解药用植物多花黄精Polygonatum cyrtonema Hua.中黄酮类化合物的生物合成途径,为黄精属植物黄酮类化合物的代谢与调控的分子机制研究提供数据,利用二代高通量测序技术,对分别培养了3个月和9个月的多花黄精组培苗根茎进行比较转录组学研究。结果显示,经序列组装与功能注释,多花黄精根茎的转录组数据经拼接共产生了73 218条unigenes序列,其中35 511条被注释;共鉴定出83条unigenes序列,分别编码18个参与黄酮类化合物合成的关键酶;在幼苗期根茎中表达的1 359个转录因子中,以bHLH最为丰富,其次是ERF、MYB-relaed、C2H2和NAC。FPKM表达分析显示,随着多花黄精块茎中黄酮类化合物的不断积累,18个酶基因中的9个显著上调,3个显著下调,6个无明显表达差异。RT-qPCR分析进一步验证了转录组FPKM结果的可靠性。本研究为解析黄精属植物黄酮类化合物的合成与积累机制提供了参考。

To understand the biosynthesis pathway of flavonoids in the medicinal plant Polygonatum cyrtonema and provide molecular data for the study on anabolism pathway and regulatory mechanism of flavonoids in Polygonatum plant, next-generation sequencing technique was emloyed to perform transcriptome sequencing on the rhizome of P. cyrtonema at development stage of 3 and 9 months.The results showed that a total of 73 218 unigenes were obtained by de novo transcriptome assembly,of which 35 511 were annotated. Eighty-three unigenes were identified from the transcriptome database, which encoded 18 key enzymes associated with flavonoids biosynthesis. Among the transcription factors expressed in rhizome of P. cyrtonema seedlings, bHLH was the main type,followed by ERF, MYB-relaed, C2H2 and NAC. Analysis of expression of 18 key enzymes based on FPKM showed that 9 were obviously up-regulated, 3 obviously down-regulated and 6 stably expressed with increasing flavonoid content in rhizome of P. cyrtonema seedlings. RT-qPCR analysis further verified the reliability of gene expression from FPKM. This present study provide a reference for further explore on the molecular mechanism on biosynthesis and accumulation of flavonoids in Polygonatum plant.