Xiao Zheng, Su Jiale, Sun Xiaobo, Li Chang, He Lisi, Cheng Shangping, Liu Xiaoqing
Institute of Leisure Agriculture, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China.
Genes Genomics. 2018 Jun;40(6):591-601. doi: 10.1007/s13258-018-0662-8. Epub 2018 Feb 3.
Rhododendron molle G. Don occupies an important phylogenetic node in the genus rhododendron with unique yellow flower and medicinal functions. However, only limited genetic resources and their genome information are available for the generation of rhododendron flowers. The next generation sequencing technologies enables generation of genomic resources in a short time and at a minimal cost, and therefore provide a turning point for rhododendron research. Our goal is to use the genetic information to facilitate the relevant research on flowering and flower color formation in R. molle. In total, 66,026 unigenes were identified, among which 31,298 were annotated in the NCBI non-redundant protein database and 22,410 were annotated in the Swiss-Prot database. Of these annotated unigenes, 9490 and 18,680 unigenes were assigned to clusters of orthologous groups and gene ontology categories, respectively. A total of 7177 genes were mapped to 118 pathways using the Kyoto Encyclopedia of Genes and Genomes Pathway database. In addition, 8266 simple sequence repeats (SSRs) were detected, and these SSRs will undoubtedly benefit rhododendron breeding work. Metabolic pathway analysis revealed that 32 unigenes were predicted to be involved in carotenoid biosynthesis. Our transcriptome revealed 32 engines that encode key enzymes in the carotenoid biosynthesis pathway, including PSY, PDS, LCYB, LCYE, etc. The content of β-carotene was much higher than the other carotenoids throughout the flower development. It was consistent with the key genes expression level in the carotenoid biosynthesis pathway by the Illumina expression profile analysis and the qRT-PCR analysis. Our study identified genes associated with carotenoid biosynthesis in R. molle and provides a valuable resource for understanding the flowering and flower color formation mechanisms in R. molle.
羊踯躅在杜鹃花属中占据着重要的系统发育节点，具有独特的黄色花朵和药用功能。然而，用于杜鹃花研究的遗传资源及其基因组信息非常有限。新一代测序技术能够在短时间内以最低成本生成基因组资源，从而为杜鹃花研究带来了转机。我们的目标是利用这些遗传信息促进对羊踯躅开花和花色形成的相关研究。总共鉴定出66,026个单基因，其中31,298个在NCBI非冗余蛋白质数据库中得到注释，22,410个在Swiss-Prot数据库中得到注释。在这些注释的单基因中，分别有9490个和18,680个单基因被归入直系同源基因簇和基因本体类别。使用京都基因与基因组百科全书通路数据库，共有7177个基因被映射到118条通路。此外，还检测到8266个简单序列重复（SSR），这些SSR无疑将有利于杜鹃花的育种工作。代谢途径分析表明，预测有32个单基因参与类胡萝卜素生物合成。我们的转录组揭示了32个在类胡萝卜素生物合成途径中编码关键酶的基因，包括PSY、PDS、LCYB、LCYE等。在整个花发育过程中，β-胡萝卜素的含量远高于其他类胡萝卜素。这与通过Illumina表达谱分析和qRT-PCR分析得到的类胡萝卜素生物合成途径中关键基因的表达水平一致。我们的研究鉴定了与羊踯躅类胡萝卜素生物合成相关的基因，并为理解羊踯躅的开花和花色形成机制提供了宝贵的资源。
