基于转录组分析揭示双色花莲‘大洒锦’花色形成机理

Transcriptome Analysis Revealed the Formation Mechanism of Floral Color of Lotus ‘Dasajin’ with Bicolor Petal

红白双色花莲品种‘大洒锦’花瓣的红色是由花色苷积累引起的,花色苷的积累与花瓣细胞酸化有关。转录组学分析发现,在红色和白色花瓣区域中共鉴定到91个差异表达基因。根据GO功能可分为分子功能、细胞组分和生物学过程3大类,其中较多基因与氧化还原活性、叶绿体类囊体和光合作用相关。KEGG代谢途径分析表明富集在代谢途径、光合作用和半乳糖代谢分支上的基因数量较多。与叶绿体和光合作用相关的差异表达基因有14个且均在红色花瓣区域下调,其中有1个是类囊体形成蛋白1基因(THF1),其低水平表达与类囊体结构异常相符。与花瓣发育相关的几个转录因子YABBY和b HLH,预测能与THF1基因的启动子结合。此外,与生长素和赤霉素合成相关及与细胞发育相关的基因在红、白花瓣区域中的差异表达使花瓣形成中凹边缘上卷的形状。推测花色苷在花瓣边缘的红色区域选择性积累与花瓣的发育相关联,即调控花瓣发育的基因可能也同时调控花色苷的积累过程,可能涉及到类囊体发育、pH的调控和细胞发育。

‘Dasajin’ lotus with red and white flower was used as the research material,it’s red color of petals was caused by anthocyanins accumulation,which was related to acidification of petal cells. A total of 91 differentially expressed genes(DEGs)were identified between red and white petals by transcriptomics analysis and these DEGs can be divided into molecular function,cellular component and biological process categories base on gene ontology(GO)analysis,among which more genes were related to redox activity,thylakoid and photosynthesis. KEGG metabolic pathway analysis indicated that genes enriched in metabolic pathway,photosynthesis and galactose metabolic branches were more abundant.Fourteen DEGs related to chloroplast and photosynthesis were down regulated in the red petals region,one of which was thylakoid morphogenetic protein 1 gene(THF1),whose low expression level was consistent with structure abnormality of thylakoid. Several transcription factors,including YABBY and bHLH,which were related to petal development,were predicted to bind the promoter of THF1 gene. In addition,several genes involved in biosynthesis of auxin and gibberellin as well as cell development were differentially expressed in red and white petal regions,leading to the formation of concave-like bowl shape of petal.Therefore,it was speculated that anthocyanins selectively accumulated in petal edge region with red color was related to petal development,that is,these genes regulating petal development may also regulate anthocyanins accumulation,which may be involved in thylakoid development,pH regulation and cell development.