睡莲品种保罗蓝花器官不同部位的转录组测序分析

Sequencing Analysis of Transcriptome in Different Parts of Nymphaea‘Paul Stetson’Flower

为探究热带睡莲花器官不同部位的花香代谢通路及参与萜类香气物质生物合成的差异表达基因,本研究借助转录组测序技术,以热带睡莲品种保罗蓝为研究对象,对其花器官的花瓣(PE,petal)、雄蕊(ST,stamen)和雌蕊(PI,pistil)3个部位进行转录组测序分析。差异表达基因分析结果显示,花瓣相对于雌蕊(PE-vs-PI)、雄蕊相对于雌蕊(ST-vs-PI)和雄蕊相对于花瓣(ST-vs-PE)的差异表达基因数目分别为7853个、7501个和2526个。GO分类和富集分析显示,3个比较组的差异表达基因主要参与了生物调节、细胞过程、代谢过程和刺激应答的生物学过程;KEGG分类和富集分析显示,PE-vs-PI的差异表达基因显著富集的KEGG通路最多,其次为ST-vs-PI,ST-vs-PE最少。从3个比较组共有的794个差异表达基因中筛选出98个参与萜类物质代谢差异表达基因,富集于4条萜类物质合成通路,且PE-vs-PI和ST-vs-PI的差异表达基因数目均高于ST-vs-PE。已知的金合欢醛和二萜贝壳杉烯合成关键基因HMGR和DXS在花瓣和雄蕊的表达量均高于雌蕊。从98个差异表达基因中随机选取了6个基因进行q RT-PCR验证,基因表达变化趋势与转录组测序一致。研究结果为热带睡莲萜类香气物质生物合成分子机制研究提供了科学参考。

To investigate the floral aroma metabolism pathways and differentially expressed genes(DEGs)involved in the biosynthesis of terpenoid aroma compounds in tropical waterlily organs,the transcriptome sequencing was used to analyze the flower organs including the petal(PE),stamen(ST)and pistil(PI)of N.‘Paul Stetson’.The number of differentially expressed genes in PE-vs-PI,ST-vs-PI,and ST-vs-PE were 7853,7501,and 2526,respectively.GO classification and enrichment analysis showed that these DEGs were mainly involved in biological regulation,cellular processes,metabolic processes,and stimulus response biological processes.KEGG annotation revealed abundant pathways with significantly enriched DEGs in PE-vs-PI,followed by ST-vs-PI,and ST-vs-PE.Ninety-eight of 794 DEGs that shared in three comparative groups were enriched in four terpenoid floral aroma synthesis pathways,and DEGs in PE-vs-PI and ST-vs-PI was higher than that in ST-vs-PE.In petals and stamens,the genes responsible for synthesis of acacia aldehyde and diterpenoid kaurene,were expressed at higher levels than in pistils.Six of 98 DEGs were randomly selected and subjected for qRT-PCR analysis,confirming the trend on transcriptional expression as revealed by transcriptome sequencing.The results provided a scientific reference for future deciphering the molecular mechanism of terpenoid aroma compounds biosynthesis in tropical waterlilies.