无瓣海桑microRNA的鉴定及功能初步分析

Identification and Preliminary Functional Analysis of microRNA in Sonneratia apetala Buch.-Ham.

探索红树植物无瓣海桑(Sonneratia apetala Buch.-Ham.)microRNA(miRNA)功能,寻找具有生长适应性调控潜能的关键miRNA,为后期功能验证实验及优良品质遗传育种奠定分子基础。本研究以三年生无瓣海桑幼苗为材料,在三代全长转录本基因集的基础上联合二代小RNA(small RNA,sRNA)测序技术及生物信息学分析方法对其进行miRNA挖掘、靶基因预测及功能解析,共鉴定出121个miRNA,包含105个已知miRNA和16个新miRNA,且miRNA表达量分布在7~394345。通过对miRNA的靶基因进行预测分析,共获得653个miRNA-靶基因关系对,对应108个miRNA和412个靶基因。功能注释分析显示这些靶基因参与各类蛋白合成、转录活性调节、MAPK信号通路和信号转导等生物活动,其中高表达量miRNA对应的靶基因显示出与生长发育、胁迫信号转导、离子转运以及胁迫响应等相关的生物学功能。miR159b-3p_1、novel_mir27和novel_mir29与其靶基因构成的调控网络分别与逆境胁迫、酶活性调节和光合作用密切相关。此外,本研究鉴定出如miR159/319、miR160/167、miR165/166、miR168、miR169、miR171、miR393、miR396、miR397/408和miR398等具有功能验证实验的参与调控植物逆境胁迫的重要miRNA。上述结果表明miRNA广泛存在于无瓣海桑基因组内并可能参与调控其生长及环境适应过程。

To lay a molecular basis for functional verification experiment and genetic breeding of superior quality,the function of miRNAs and potential miRNAs which could play vital roles in growth and environmental adaptation was explored in Sonneratia apetala Buch.-Ham.In this study,miRNAs were identified,and target genes were analyzed through second-generation sRNA sequencing technology and bioinformatics analysis based on the full-length transcriptome of a three-year-old S.apetala.A total of 121 miRNAs were identified,including 105 known miRNAs and 16 novel miRNAs,with the expression level ranging from 7 to 394345.Furthermore,653 pairs of miRNA-mRNA were found,corresponding to 108 miRNAs and 412 target genes.The results of functional annotation analysis revealed that these target genes were involved in various biological activities such as protein synthesis,transcription activity regulation,MAPK signaling pathway,and signal transduction.Target genes of miRNAs that exhibited highest expression showed important biological functions relating to growth and development,stress signal transduction,ion transport and stress response.Regulatory networks between miR159 b-3 p_1,novel_mir27,novel_mir29 and their corresponding targets were closely related to stress,enzyme activity regulation and photosynthesis,respectively.Additionally,miRNAs which were confirmed to participate in the regulation of plant stress response by functional experiments were detected in this study,like miR159/319,miR160/167,miR165/166,miR168,miR169,miR171,miR393,miR396,miR397/408 and miR398.These results indicated that miRNAs existed extensively in S.apetala genome and may play an essential role in the growth and environmental adaptation process.