College of Life Sciences, Jilin Agricultural University, Changchun 130118, China.
Department of bioengineering, Jilin Engineering Vocational College, Siping 136001, China.
Genes (Basel). 2019 Dec 26;11(1):31. doi: 10.3390/genes11010031.
(Lam.) Aschers (HPA), a species in the family Liliaceae, is an important landscaping plant and herbaceous ornamental flower. However, because the flower has only two colors, white and purple, color matching applications are extremely limited. To date, the mechanism underlying flower color regulation remains unclear.
In this study, the transcriptomes of three cultivars- (HP, white flower), (HC, purple flower), and (HS, purple flower)-at three flowering stages (bud stage, initial stage, and late flowering stage) were sequenced with the Illumina HiSeq 2000 (San Diego, CA, USA). The RNA-Seq results were validated by qRT-PCR of eight differentially expressed genes (DEGs). Then, we further analyzed the relationship between anthocyanidin synthase (ANS), chalcone synthase (CHS), and P450 and the flower color regulation by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Eukaryotic Orthologous Groups (KOG) network and pathway enrichment analyses. The overexpression of CHS and ANS in transgenic tobacco petals was verified using qRT-PCR, and the petal colors associated with the overexpression lines were confirmed using absorbance values.
Over 434,349 transcripts were isolated, and 302,832 unigenes were identified. Additionally, through transcriptome comparisons, 2098, 722, and 606 DEGs between the different stages were found for HP, HC, and HS, respectively. Furthermore, GO and KEGG pathway analyses showed that 84 color-related DEGs were enriched in 22 pathways. In particular, the flavonoid biosynthetic pathway, regulated by , , and the cytochrome P450-type monooxygenase gene, was upregulated in both purple flower varieties in the late flowering stage. In contrast, this gene was hardly expressed in the white flower variety, which was verified in the and overexpression transgenic tobacco petals.
The results suggest that CHS, ANS, and the cytochrome P450s-regulated flavonoid biosynthetic pathway might play key roles in the regulation of flower color in HPA. These insights into the mechanism of flower color regulation could be used to guide artificial breeding of polychrome varieties of ornamental flowers.
（Lam.）Aschers （HPA），百合科的一个物种，是一种重要的景观植物和草本观赏花卉。然而，由于花只有两种颜色，白色和紫色，颜色匹配的应用极其有限。迄今为止，花颜色调控的机制尚不清楚。
本研究采用 Illumina HiSeq 2000（圣地亚哥，CA，美国）对三个品种（HP，白花）、（HC，紫花）和（HS，紫花）的三个开花阶段（花蕾期、初花期和晚花期）的转录组进行测序。通过对 8 个差异表达基因（DEGs）的 qRT-PCR 验证了 RNA-Seq 结果。然后，我们通过基因本体论（GO）、京都基因与基因组百科全书（KEGG）和真核同源物组（KOG）网络和途径富集分析进一步分析了查尔酮合酶（CHS）、类黄酮合酶（ANS）和 P450 与花颜色调控之间的关系。通过 qRT-PCR 验证了 CHS 和 ANS 在转基因烟草花瓣中的过表达，并用吸光度值验证了与过表达系相关的花瓣颜色。
分离出超过 434349 个转录本，鉴定出 302832 个单基因。此外，通过转录组比较，HP、HC 和 HS 之间在不同阶段分别发现了 2098、722 和 606 个 DEGs。此外，GO 和 KEGG 途径分析表明，84 个与颜色相关的 DEGs 富集在 22 条途径中。特别是，黄酮类生物合成途径受 、 和细胞色素 P450 型单加氧酶基因的调控，在晚花期的两个紫色花品种中上调。相比之下，在白花品种中，该基因几乎不表达，这在 和 过表达的转基因烟草花瓣中得到了验证。
结果表明，CHS、ANS 和细胞色素 P450 调控的黄酮类生物合成途径可能在 HPA 花颜色调控中起关键作用。这些对花颜色调控机制的深入了解可用于指导观赏花卉多色品种的人工选育。
