枫香叶片变色期全长转录组测序及分析

Sequencing and analysis of full-length transcriptome from Liquidambar formosana leaves in discoloration stage

关键词:  枫香, 叶片变色期, 单分子实时测序技术, 全长转录组, 基因功能注释

Key words:  Liquidambar formosana, leaf discoloration stage, single-molecule real-time sequencing technology, full-length transcriptome, gene function annotation

摘要:

枫香因其树形优美,入秋后叶色红艳或橙黄,极具观赏价值,是优良的景观生态树种。为了解枫香叶片变色及其次级代谢过程的遗传基础,该文以枫香5个叶片变色期叶片混合样品为材料,利用单分子实时测序技术(PacBio平台)对其进行全长转录组测序。结果表明:(1)全长转录组测序共获得41.04 Gb的高质量数据,从中鉴定出全长非嵌合序列563 180条,通过聚类和去冗余,获得27 269条高质量全长转录本。在27 269条全长转录本中预测到2 035条长链非编码RNA(lncRNA),并检测出14 892个简单重复序列(SSR)位点和1 856个转录因子。(2)基因注释结果表明,NR、GO、COG、KEGG 等8个数据库共注释了24 857条转录本,KEGG数据库共获得了124个条代谢途径,主要有核糖体、碳代谢、氨基酸生物合成等,在类黄酮和叶绿素代谢途径中分别有49和71个转录本参与。上述结果初步揭示了枫香叶片变色期转录组信息以及功能特性,为后续研究枫香叶片变色分子机制、色素代谢合成途径和调控、相关功能基因克隆以及叶色改良提供基础数据。

Abstract:

Liquidambar formosana is an excellent landscape ecological tree species because its beautiful tree shape and red or orange leaves in autumn. In order to understand the genetic basis of discoloration and secondary metabolism of L. formosana leaves, the mixed samples of L. formosana leaves in five leaf discoloration stages were used for full-length transcriptome sequencing using single-molecule real-time sequencing technology(PacBio platform). The results were as follows:(1)High-quality 41.04 Gb data were obtained by full-length transcriptome sequencing, from which 563 180 full-length non-chimeric sequences were identified, and 27 269 high-quality full-length transcripts were obtained by clustering and de-redundancy. In 27 269 full-length transcripts, 2 035 long-chain non-coding RNA(lncRNA)were predicted, and 14 892 simple sequence repeat(SSR)sites and 1 856 transcription factors were detected.(2)The results of gene annotation showed that a total of 24 857 transcripts were annotated in eight databases such as NR, GO, COG and KEGG, etc., 124 metabolic pathways were obtained in KEGG database, including ribosome, carbon metabolism, amino acid biosynthesis and so on, and 49 and 71 transcripts were involved in flavonoid and chlorophyll metabolism respectively. The above results preliminarily reveal the transcriptome information and functional characteristics of L. formosana leaves during the leaf discoloration stage, and provide basic data for the follow-up study of the molecular mechanism of leaf discoloration, the pathway and regulation of pigment metabolism and synthesis, the cloning of related functional genes and the improvement of leaf color.