材料，利用高通量测序和生物信息学分析，获得野生蕉不同颜色果皮组织的miRNA表达谱，筛选不同颜色果皮差异表达的miRNA并预测相关靶基因，通过靶基因分析，获得与调控野生蕉果皮颜色可能相关的信号通路。结果从不同颜色野生蕉果皮中共获得34.11兆条原始读长，经过滤后得到28.73兆条clean reads，从中鉴定出132个已知的miRNA序列和122个新的miRNA;筛选出36个差异表达miRNA，其中10个在紫色果皮中上调表达，26个在绿色果皮中上调表达。表达量最高的miRNA为mit-miR167，而差异倍数最大的为mit-miR172a-3p-2。差异表达miRNA共预测出1164个靶基因可能参与野生蕉果皮颜色调控，并主要在DNA结合、离子跨膜运输活动等功能和植物病原互作等途径富集。其中，有7个基因直接与苯丙烷生物合成途径相关，主要受到miR156和miR482家族的调控。同时，选取6个差异表达miRNA进行定量验证，结果表明，3个miRNA在绿色果皮中上调表达，3个miRNA在紫色果皮中上调表达，定量结果与高通量测序的结果一致。本文通过高通量测序获得了野生蕉果皮miRNA表达谱，并通过生物信息学分析得到可能和调控野生蕉果皮颜色性状相关的miRNA和代谢通路。综上所述，野生蕉果皮颜色可能受到多种miRNA的调控，并涉及多个代谢通路，这有助于进一步了解果皮花青素转录后水平的调控过程，并对进一步的功能验证奠定基础。
关键词 野生蕉;果皮;花青素;miRNA;差异表达中图分类号 S686; S668.1 文献标识码 A
miRNA Expression Profile and Target Gene Analysis of Different Color Peels in Wild Banana （Musa itinerans）
DENG Sufang1，2， CHENG Chunzhen1， LIN Yuling1， LAI Zhongxiong1*
1. Institute of Horticultural Biotechnology， Fujian Agriculture and Forestry University， Fuzhou， Fujian 350002， China; 2. Agricultural Ecology Institute， Fujian Academy of Agricultural Sciences， Fuzhou， Fujian 350013， China
Abstract In this paper， the transcriptome sequencing of different color peels （green and purple） of Minhou wild banana （Musa itinerans） was carried out to investigate the role and the possible regulatory pathways of miRNA involved in the post-transcriptional level regulation of peel color， which would lay the foundation for the study of the peel color molecular regulation mechanism of the genus Musa. In the experiment， different color （purple and green） peel tissues on the same fruit comb of wild banana were used for miRNA analysis. Through miRNA sequencing and bioinformatics analysis， the miRNA expression profiles of different color peel tissues in wild banana were obtained. The differentially expressed miRNAs were screened and the related target genes were predicted. Through the target gene analysis， the signal pathways which is related to peel color traits were proposed. As a result， a total of 34.11 million original reads and 28.73 million clean reads were obtained from the green and purple peel tissues. Among them， 132 known miRNAs and 122 new miRNAs were identified; 36 differentially expressed miRNAs were screened out， of which 10 were up-regulated in purple peel and 26 were up-regulated in green peel. The miRNA with the highest expression was mit-miR167， and the one with the largest difference was mit-miR172a-3p-2. A total of 1164 target genes of differentially expressed miRNAs were predicted， which may be involved in the regulation of wild banana peel color， and were mainly eiched in functions such as DNA binding， anion transmembrane transporter activity， and plant pathogen interaction pathways. Among them， there were 7 genes directly related to the phenylpropanoid biosynthesis pathway， and were mainly regulated by the miR156 and miR482 families. At the same time， six differentially expressed miRNAs were selected for quantitative verification. The results showed that three miRNAs were up-regulated in green peel and three miRNAs were up-regulated in purple peel. The quantitative results were consistent with the results of high-throughput sequencing. In this study， the miRNA expression profiles of wild banana peels were obtained， and the miRNAs and metabolic pathways which may be related to the regulation of color traits of wild banana peel were obtained by bioinformatics analysis. These results indicated that the color trait of wild banana peel may be regulated by a variety of miRNAs and involves multiple metabolic pathways， which would help to further understand the post-transcriptional level regulation of anthocyanins in the peel and lay the foundation for further functional verification.
