花生异型雄蕊转录组分析

Analysis on transcriptome from heteromorphic stamens of Arachis hypogaea

以花生(Arachis hypogaea Linn.)品种‘Florunner’为研究对象,利用RNA-seq技术对花生异型雄蕊进行转录组测序;在此基础上,运用Nr、KOG、GO和KEGG数据库进行同源序列比对和基因功能分析。结果显示:花生异型雄蕊转录组测序共获得数据量约31.46 G,其中,clean reads所占比例均在96.0%以上;经过组装和拼接后得到197193个contigs,片段总长度240463900 bp,最长片段为15810 bp,非冗余unigenes片段的平均长度为1219 bp,GC含量为39.1%,片段长度N50为1966 bp;长度大于等于1000 bp的unigenes占unigenes总数的43.4%,表明组装完整性较高,可用于注释分析。与Nr数据库的比对结果显示:共有129223个unigenes注释到Nr数据库,占unigenes总数的65.5%;其中,1×10^-100<E≤1×10^-5的unigenes占54.2%,说明注释的unigenes序列与Nr数据库的同源序列具有高度相似性;共有106900个unigenes注释到已探明的同源序列中,占注释unigenes总数的82.7%,且与大豆〔Glycine max(Linn.)Merr.〕和蒺藜苜蓿(Medicago truncatula Gaertn.)等同科种类的序列同源性较高。基因功能分析结果显示:共有133387个unigenes注释到25个KOG功能类别上,且功能明确的unigenes均与配子体发育功能相关,其中,注释到信号转导机制功能的unigenes数量最多(17135)。共有48497个unigenes注释到生物过程、细胞组分和分子功能3大类55个亚类的GO功能类别上,其中,与核酸代谢过程、磷酸化、转录调节、核、核糖体、ATP结合、转录因子和钙离子结合相关的亚类中unigenes高度富集。共有30428个unigenes注释到2708个酶功能,映射了354个KEGG代谢通路,可分为遗传信息处理、细胞过程、生物系统、环境信息处理和代谢5大类32个亚类,其中,与代谢相关通路的unigenes数量最多(14231)。综合分析结果表明:在花生异型雄蕊转录组中,多数unigenes的功能与雄蕊产生雄配子的功能有关,且部分基因可参与不同的代谢途径,对花生异型雄蕊的器官发生和花药形成具有重要作用。

Taking cultivar‘Florunner’of Arachis hypogaea Linn.as research object,transcriptome sequencing was conducted on its heteromorphic stamens by using RNA-seq technology;on the basis,homologous sequence alignment and gene function analysis were conducted by using Nr,KOG,GO and KEGG databases.The results show that about 31.46 G of data are obtained by transcriptome sequencing of heteromorphic stamens of A.hypogaea,in which,clean reads account for above 96.0%;197193 contigs are obtained after assembling and splicing,and the total length of fragments is 240463900 bp,the longest fragment is 15810 bp;the average length of non-redundant unigenes fragment is 1219 bp,the GC content is 39.1%,and the fragment length N50 is 1966 bp;unigenes with a length greater than or equal to 1000 bp account for 43.4%of total unigenes number,indicating that the assembly integrity is relatively high,and can be used for annotation analysis.The alignment result with Nr database shows that there are 129223 unigenes annotated in Nr database,accounting for 65.5%of total unigenes number;in which,unigenes of 1×10^-100<E≤1×10^-5 account for 54.2%,indicating that annotated unigenes sequences have high similarity with homologous sequences in Nr database;there are 106900 unigenes annotated in known homologous sequences,accounting for 82.7%of total annotated unigenes number,and have high sequence homology with plants of the same family,such as Glycine max(Linn.)Merr.and Medicago truncatula Gaertn.,etc.The gene function analysis result shows that there are 133387 unigenes annotated in 25 KOG functional categories,and functional unigenes are all associated with gametophyte development function,in which,number of unigenes annotated in signal transduction mechanism function is the largest(17135).There are 48497 unigenes annotated in 55 subcategories belonging to 3 GO functional categories including biological process,cellular component and molecular function,in which,unigenes are highly enriched in subcategories related to nucleic acid metabolic process,phosphorylation,transcriptional regulation,nucleus,ribosome,ATP binding,transcription factor and calcium binding.There are 30428 unigenes annotated in 2708 enzyme function mapping to 354 KEGG metabolic pathways,which can be divided into 32 subcategories belonging to 5 categories including genetic information processing,cellular process,organismal system,environmental information processing and metabolism,in which,number of unigenes in pathway related to metabolism is the largest(14231).The comprehensive analysis result shows that in the transcriptome from heteromorphic stamens of A.hypogaea,function of most unigenes is associated with the function of stamens producing male gametes,and some genes are involved in different metabolic pathways,and play an important role in the organogenesis of heteromorphic stamens and formation of anther of A.hypogaea.