越橘果实转录组及R2R3-MYB转录因子分析

Analysis of Transcriptome and R2R3-MYB Transcription Factors in Blueberry Fruit

以‘泽西’越橘(Vaccinium corymbosum‘Jersey’)不同发育阶段的果实为试材,构建De novo转录组测序文库并进行数据分析,利用Web Logo 3、CLC Sequence Viewer 6等软件和荧光定量PCR技术对所获数据中的R2R3-MYB转录因子进行生物信息学分析和表达分析。结果表明,转录组测序共获得有效数据6.01 Gb,通过组装得到Unigene序列60 481个。功能注释结果显示,有39 612个Unigene可以注释到GO和COG等数据库上;20 869个Unigene无匹配信息。利用GO和COG分类工具可将这些序列分别划分为55个和25个功能类别,涉及信号转导和转录调控等功能。利用所获数据分析越橘R2R3-MYB基因,结果表明共得到21个R2R3-MYB。序列分析显示,这21个基因均含有完整的R2R3-MYB区域,在此区域内2(G)和4(W)等30个氨基酸保守不变。进化树分析结果显示,越橘R2R3-MYB基因分为11个亚组。其中,S4、S5和S6亚组中有6个基因涉及到花青苷生物合成。荧光定量PCR结果分析显示,这6个基因在果实发育的7个阶段均能表达,但表达模式不同,这6个基因可能对越橘果实着色具有一定作用。

The transcriptomes of blueberry fruit（Vaccinium corymbosum‘Jersey＇）were analyzed by sequencing transcripts combined from fruits of different development stages. Twenty-one R2R3-MYB genes were identified and further analyzed by Web Logo 3,CLC Sequence Viewer 6 and real-time PCR. In total,6.01 Gb transcriptomic data were obtained,from which 60 481 unigenes were assembled. The quality of the data was proven acceptable. Functional annotation analysis showed that 39 612 unigenes had homologs in GO and COG public database though no hits were found for the rest 20 869 unigenes. These unigenes were assigned into 55 and 25 function categories including signal transduction mechanisms,transcription and metabolism etc. by GO and COG terms,respectively. The putative protein sequences of the 21 R2R3-MYB genes contained the conserved domain of R2R3 and the conserved amino residues of 2（G）and 4（W）. Phylogenetic analysis showed that the blueberry R2R3-MYB genes could be divided into 11 subclasses. Six genes in S4,S5 and S6 subclass were thought to be involved in regulating the biosynthesis of anthocyanin. RT-PCR results indicated that six genes were expressed in seven stages of fruit development though differently expressed pattern. Six genes may play an important role in pigmentation.