桑葚幼果的落果与正常果的果柄转录组分析

Transcriptome analysis of abscised and normal surviving young fruit of Morus alba

【目的】果实的脱落是一种常见的生理现象,会在一定程度上限制果实的产量。探究桑葚幼果在脱落过程中的代谢及生化反应,可为桑葚的脱落机制研究提供参考。【方法】通过高通量测序对白桑Morus alba幼果在落果和正常果的果柄离区进行转录组测序,筛选差异表达基因,并对其进行功能注释和代谢通路分析,采用实时荧光定量PCR技术对转录组数据进行验证。【结果】经华大基因转录组测序分析共计获得262.92 Mb的原始序列;桑葚幼果果柄在2种状态下共筛选到10481个差异表达基因,其中,有5239个差异表达基因上调表达,5242个差异表达基因下调表达。经基因本体数据库(GO)功能富集分析,共发现37个显著性条目,大多数差异基因具有催化活性、膜的组成成分、氧化还原酶活性、膜的内在成分等功能;京都基因与基金组百科全书(KEGG)富集分析发现:大多数差异表达基因集中在柠檬酸循环、植物激素信号转导途径、黄酮类生物合成等代谢通路上。【结论】桑葚在脱落过程中受植物激素的调控,氨基酸、黄酮类次生代谢物和碳水化合物等物质也能调控果实脱落。

[Objective]This study,with mulberry(Morus)fruits as the subjects,is aimed to conduct an investigation into its fruit abscission,a common physiological process which limits the yield of fruit so as to clarify the underlying abscission mechanism of the metabolism and biochemical reactions.[Method]Highthroughput sequencing was employed to conduct transcriptome analysis of the young fruit of Morus alba in the abscission zone between the abscised and normal surviving mulberry fruits to screen the differentially expressed genes before they were subjected to functional annotation and metabolic pathway analysis,and the verification of transcriptome data using real-time quantitative PCR technology.[Result]A total of 262.92 Mb of raw reads and 10481 differentially expressed genes were obtained by Beijing Genomics institution(BGI,Shenzhen,China),of which 5239 were up-regulated,whereas 5242 were down-regulated;As was shown by the GO functional enrichment analysis,a total of 37 significant items were found,and most of the differentially expressed genes were featured with catalytic activity,membrane composition,oxidoreductase activity and membrane intrinsic components.It was shown by the KEGG enrichment analysis that most differentially expressed genes were concentrated in metabolic pathways such as citric acid cycle,plant hormone signal transduction pathway,and flavonoid biosynthesis.[Conclusion]Mulberry is regulated by plant hormones and substances such as amino acids,flavonoid secondary metabolites and carbohydrates during the abscission process.