金花茶花瓣转录组分析及花瓣发育调控基因挖掘

Transcriptome Analysis of Petals and to Explore Related Genes in Petal Development of Camellia nitidissima

花瓣大小是影响金花茶(Camellia nitidissima)观赏价值的主要因素之一,但金花茶花瓣发育形成机制尚不清楚。将金花茶花瓣发育过程划分为幼蕾期(S1)、初蕾期(S2)、显色期(S3)、半开期(S4)、盛开期(S5)五个阶段,利用RNA-seq技术分析花发育过程中转录组的动态变化,以期对金花茶花瓣发育形成的转录机理进行初步探究。通过对金花茶花瓣发育过程中的差异表达基因进行富集分析和趋势分析,发现生长素转导途径所含差异表达基因数量最多,部分AUX1/LAX共转运体、AUX/IAA基因、SAUR等生长素应答基因在开花过程中明显上调,表明生长素是调控花瓣生长重要的调控因子。MYB、bHLH、锌指蛋白等转录因子、木葡聚糖内糖基转移酶/水解酶(XTH)、果胶酯酶(PE)、果胶裂解酶(PL)等部分下游功能基因,其中XTH显著富集于GO分类中的水解酶活性,表明它们可能对金花茶花瓣的生长起重要调控作用。此外,对FT、SOC1、AP3、PI、SEP3等开花调控关键基因在金花茶花瓣发育过程中的表达情况进行了分析,结果表明这些基因主要以中低表达为主。高表达基因进行KEGG富集分析结果表明,次生代谢物质合成伴随着金花茶花瓣的整个发育过程。这些结果为进一步揭示金花茶花瓣发育的转录调控机制奠定了理论基础。

Petal size was one of the main factors affecting the ornamental value of Camellia nitidissima,but its formation mechanism was unclear.In this study,the petal development process of C.nitidissima was divided into five developmental stages:young bud stage(S1),early bud stage(S2),turning yellow stage(S3),semiblooming stage(S4)and full bloom stage(S5)respectively.The dynamic changes of transcriptome during flower development were analyzed by RNA-seq technique.Using enrichment analysis and trend analysis of differentially expressed genes,it was found that the number of differentially expressed genes in auxin transduction pathway was the largest,and some auxin response genes such as AUX1/LAX cotransporters,AUX/IAA genes and SAURs were significantly up-regulated during flowering respectively,indicated that auxin was an important regulator of petal growth.Transcription factor genes such as MYB,bHLH and zinc finger protein genes were obviously up-regulated or down-regulated respectively,and some downstream functional genes such as xyloglucan endotransglucosylase/hydrolase(XTH),pectin esterase(PE)and pectin lyase(PL)were also showed significant changes respectively.The results also suggested that these genes may be candidate genes involved in petal development.In addition,the expressions of some genes related to flowering regulation,such as FT,SOC1,AP3,PI,SEP3,etc.,were analyzed during the petal development of C.nitidissima,but the results showed that their expressions were mainly medium and low expression.Besides,the results of KEGG enrichment analysis of highly expressed genes revealed that the synthesis of secondary metabolites was accompanied by the whole petal development of C.nitidissima.All these results would lay a theoretical foundation for further researches of the regulation mechanism of petal development of C.nitidissima.