黄芩bHLH转录因子基因家族生物信息学及表达分析

Analysis of bioinformatics and expression level of bHLH transcription factors in Scutellaria baicalensis

目的通过生物信息学方法,克隆黄芩Scutellaria baicalensis bHLH基因,并初步探究其功能。方法使用BLAST软件从黄芩cDNA文库中筛选出bHLH基因,克隆其全长cDNA序列,测序验证后使用ORF Finder预测开放阅读框,并进行蛋白序列特征分析,使用荧光定量PCR方法比较bHLH基因在不同器官以及受赤霉素刺激下的表达情况。结果克隆的6个bHLH转录因子基因(bHLH1~3,bHLH5~7),分属6个亚家族,其中2个有完整的开放阅读框。bHLH基因相对表达水平分析发现,100μmol/L GA3处理后bHLH2、bHLH3表达量升高,bHLH1、bHLH5~7表达量降低;bHLH基因在黄芩的根与花中表达量较高,其中bHLH1、bHLH2、bHLH5、bHLH7在花中表达量最高,bHLH3在根中表达量最高;bHLH基因与黄酮类成分生物合成及调控基因表达水平具有一定相关性。结论为进一步完善黄芩黄酮类成分的分子调控网络奠定基础。

Objective The information of bHLH transcription factor genes from transcriptome dataset of Scutellaria baicalensis was predicted by bioinformatics methods and the gene expression analysis was used to deduce its probable function. Methods The bHLH genes were screened from the transcriptome dataset of S. baicalensis by using BLAST comparison software. Then the open reading frames（ORFs） from the full-length of cDNA of bHLH genes were predicted by ORF Finder online tool, and its protein characteristics were analyzed using bioinformatic method. The expression of bHLH genes was detected by q PCR in different organs and treatments stimulated by Gibberellin A3（GA3）. Results Six genes of bHLH transcription factors were obtained, which belonged to six subfamilies of bHLHs of A. thaliana, two of which had completed ORFs. The results of gene expression showed that： The expression of bHLH2 and bHLH3 increased after 100 μmol/L GA3 treatment, and the expression of bHLH1, bHLH5, bHLH6 and bHLH7 decreased. The bHLH gene had the highest expression level in roots and flowers of S. baicalensis of them, among which bHLH1, bHLH2, bHLH5 and bHLH7 had highest expression in flowers and bHLH3 had highest expression in root. There was a correlation between bHLH gene and expression of biosynthesis and regulation genes of flavonoid. Conclusion These results provided the basis for further improving the molecular regulation network of flavonoids of bHLH genes in S. baicalensis.