苦茶全长转录组测序及基因结构分析

Full-length Transcriptome and Gene Structure Analysis of Kucha(Camellia sinensis)

为进一步探究苦茶特异性状形成的遗传基础,基于PacBio对苦茶进行Iso-Seq,最终得到Polished consensus序列132334个,其中有26184个为已知基因的新转录本,7115个为新基因,同时鉴定得到21106个SSR位点;基因结构分析结果中,4892个基因发生了可变剪切事件,其中内含子滞留事件占比最大;预测得到1918个新的转录因子,778个LncRNA。比较KEGG(10976+5626)、KOG(6296+1896)、GO(6221+575)3大数据库功能注释情况,发现注释到KEGG的转录本数最多,其中多个转录本注释到与茶叶品质和苦茶特异性状形成相关的代谢途径,如苦茶碱等嘌呤生物碱代谢(74+17)、氨基酸代谢(409+69)、苯丙烷生物合成(70+18)和萜类物质生物合成(152+31)等(括号内数值为未比对到基因组的转录本和新转录本数量)。这些发现将有助于苦茶特异性状相关基因标记的开发、并为其形成的机理及遗传机制的研究奠定基础。

Kucha is a kind of special germplasm resource of tea plant in China,which has many characteristics different from the conventional tea cultivars.To further explore the genetic basis for the formation of special properties of Kucha,PacBio Iso-Seq was used to multiple tissues from Kucha for transcriptome sequencing.Totally 132334 polished consensus sequences were obtained,of which 26184 were new transcripts of known genes,7115 were new genes,and 21106 SSR sites were identified.The gene structure analysis showed that 4892 genes had alternative splicing,of which retantied intron events accounted for the largest proportion.1918 new transcription factors and 778 LncRNAs were predicted.By comparing the functional annotations of the three major databases of KEGG(10976+5626),KOG(6296+1896),and GO(6221+575),it was found that the largest number of transcripts were annotated to KEGG,and many of the transcripts,such as metabolism of purine alkaloids,theacrine(74+17),amino acid metabolism(409+69),phenylpropane biosynthesis(70+18)and terpenoid biosynthesis(152+31),were annotated to metabolic pathways related to tea quality and specific properties formation of Kucha.The findings in this paper will help the development of gene markers related to specific properties in Kucha and lay the foundation for the formation mechanism and genetic mechanism.