基于油桐种子3个不同发育时期转录组的油脂合成代谢途径分析

Analysis of oil synthesis metabolism pathways based on transcriptomechanges in tung oil tree's seeds during three different development stages

油桐是我国重要的木本油料植物,过去对油桐的研究主要集中于栽培和常规育种,与油桐种仁油脂合成相关的分子机理研究还未见报道。文章采用RNA-seq技术对油桐种子油脂合成的3个不同时期的转录组进行比较,获得了大量差异表达的Unigene序列。在此基础上,通过GO分类和Pathway富集性分析将这些差异表达Unigene归类于128个代谢途径,其中包含与油脂合成相关的脂肪酸生物合成和甘油磷脂代谢途径。桐酸经脂肪酸生物合成途径合成后通过甘油磷脂代谢途径以桐油的形式贮存。将这两个代谢途径的Unigene序列在KEGG数据库中进行比对,获得了一些关键酶的同源蛋白质。文章通过对编码这些同源蛋白质的基因在油桐种子油脂合成期的表达模式进行分析,以期为油桐油脂合成,尤其是桐酸合成机理的解析提供理论参考,并为油桐的遗传改良提供潜在的基因资源,从而提高油桐的单位面积产量。

Tung oil tree （Verniciafordii） is one of the important woody oil plants in China. Past researches on tung oil tree mainly focu on the cultivation and conventional breeding while the molecular mechanisms related to tung oil synthesis are still uncovered. We compared transcriptome of tung oil tree＇s seeds at three different oil synthesis stages using RNA-seq technology and then obtained a lot of differentially expressed Unigenes. Through GO classification and pathway enrichmentanalysis, all of these differentially expressed Unigenes were classified into 128 metabolism pathways including fatty acid biosynthesis and glycerophospholipid metabolism which are involved in oil synthesis. Some homologous proteins of key enzymes were obtained when the sequences of the Unigenes within these two pathways were aligned against KEGG data- base. Through analysis of expression profiles of these key enzyme genes during seed＇s oil synthesis stage, this research not only shed light on elucidation of plant oil synthesis but also provides candidate genes for genetic improvement of tung oil tree thereby increasing the yield per unit area of tung oil tree.