基于转录组的八角挥发油合成相关基因挖掘与分析

Discovery and analysis of volatile oil synthesis related genes in Illicium verum based on transcriptome sequencing

关键词:  八角, 叶片, 挥发油合成, 草蒿脑, 转录组分析

Key words:  Illicium verum, leaf, volatile oil synthesis, estragole, transcriptome analysis

摘要:

为更好地挖掘八角(Illicium verum)挥发油合成相关基因,该文对挥发油性状差异显著的优良无性系桂角69号及普通品种砧01号叶片进行了转录组测序及组装注释,并对差异表达基因进行了GO分类和KEGG通路分析。结果表明:(1)转录本经组装后获得84 182条序列,使用NR、NT、Swiss-Prot、KEGG、KOG、GO和Pfam数据库进行序列比对,共注释了59 161条序列,筛选出30 572个差异表达基因。与砧01号相比,桂角69号叶片中上调基因有15 025个,下调基因有15 547个。(2)GO分类结果显示共有20 287个差异基因被注释。KEGG分析结果表明,有21 600个差异基因被注释到133条KEGG通路上,其中挥发油合成相关的单萜生物合成通路、萜类骨架生物合成通路、苯丙素合成通路中的芳樟醇合酶、月桂烯合酶、香叶基香叶基焦磷酸合酶、肉桂酰辅酶A还原酶、咖啡酸3-O-甲基转移酶、肉桂醇脱氢酶等关键酶基因呈差异表达。(3)转录因子分析发现差异表达基因分布于31个转录因子家族,其中MYB家族序列数量最多。该文利用转录组测序技术分析八角优良无性系与普通品种叶片的差异基因及其相关功能和代谢通路,获得的候选基因为深入探究挥发油特征组分的合成机制以及八角的分子育种提供了参考。

Abstract:

In order to identify volatile oil synthesis related genes in Illicium verum, transcriptome sequencing and assembly annotation were carried out on the leaves of the superior clone Guijiao 69 and common variety Zhen 01, two varieties with significant difference in volatile oil content. Then GO and KEGG pathways analyses of differentially expressed genes(DEGs)were performed. The results were as follows:(1)A total of 84 182 Unigenes were obtained after transcripts assembly, and 59 161 Unigenes were annotated in NR, NT, Swissprot, KEGG, KOG, GO, and Pfam databases. A total of 30 572 DEGs were obtained after filtering the low abundance genes, and 15 025 up-regulated and 15 547 down-regulated genes were identified in Guijiao 69 compared to the common variety Zhen 01.(2)GO classification results showed that 20 287 DEGs were annotated. In addition, 21 600 DEGs were involved in 133 KEGG pathways. Among them, genes encoding the key enzymes related to volatile oil synthesis such as linalool synthase, myrcene synthase, geranyl geranyl pyrophosphate synthase, cinnamoyl CoA reductase, caffeic acid 3-O-methyltransferase and cinnamyl alcohol dehydrogenase were differentially expressed and enriched in monoterpene biosynthesis pathway, terpene skeleton biosynthesis pathway and phenylpropanoid biosynthesis pathway.(3)Transcription factor analysis showed that the DEGs were distributed in 31 transcription factor families, of which MYB family had the most Unigenes. In this study, transcriptome sequencing was performed to analyze the DEGs superior clones and common varieties of I. verum as well as their related functions and pathways. The candidate genes obtained provide the references for further exploring the synthesis mechanism of characteristic components of volatile oil and molecular breeding of I. verum.