木槿两个花色品种的花瓣转录组测序分析

Transcriptome Sequencing Analysis of Petals of Two Hibiscus syriacus Cultivars with Different Flower Colors

为探究木槿花瓣的呈色机理,本研究对木槿白花品种‘点雪’和粉花品种‘粉红巨人’的花瓣进行了转录组测序及生物信息学分析。结果表明,在两个品种间共得到18449个差异表达基因。与白花相比,粉花有9885个基因的表达量升高,8564个基因表达量降低。差异表达基因的KEGG富集结果表明,表达上调的基因主要参与光合作用、淀粉和蔗糖代谢、光合生物的碳固定、类黄酮生物合成以及苯丙烷生物合成等代谢途径,而表达量下降的基因主要在戊糖和葡萄糖醛酸的相互转化、苯丙烷的生物合成及玉米素的生物合成等代谢途径。在花青苷生物合成途径中,与白花相比,粉花中C4H、CHS、CHI和DFR的表达量显著增加,F3H和LDOX的表达量显著降低,而HCT和F3’H的同源基因有的表达上调,有的下调。这一结果表明C4H、CHS、CHI以及DFR可能是导致粉花品种花色呈色的关键基因。本研究获得了木槿白花和粉花品种间的差异表达基因及功能注释信息,为木槿花色调控提供了一定的理论依据,也为后续分子育种提供了科学参考。

To elucidate the mechanism of flower coloration,RNA sequence analysis was performed using petals of pink-flower cultivar’Fenhongjuren’and white-flower cultivar’Dianxue’of Hibiscus syriacus as materials in the present study.A total of 18449 differentially expressed genes(DEGs)were found between two cultivars,including9885 up-regulated and 8564 down-regulated genes in the pink-flower cultivar compared with the white one.KEGG enrichment analysis of these DEGs revealed that the up-regulated genes were mainly involved in metabolic pathways such as photosynthesis,starch and sucrose metabolism,flavonoid biosynthesis,and phenylpropanoid biosynthesis,while genes with decreased expression were in metabolic pathways such as pentose and glucuronate interconversions,phenylpropanoid biosynthesis,and zeatin biosynthesis.In the anthocyanin biosynthetic pathway,the expressions of C4H,CHS,CHI,and DFR were significantly increased,and those of F3H and LDOX were decreased in pink-flower cultivar compared to the white one,while some homologues of HCT and F3’H were up-regulated and some were down-regulated.These results suggest that C4H,CHS,CHI and DFR may play key roles in flower coloration in the pink-flower cultivar.In this study,DEGs between pink-and white-flower cultivars of Hibiscus syriacus and their functional annotations were investigated,which could provide a theoretical basis for the regulation of flower color and a scientific reference for subsequent molecular breeding.