Genome-wide characterization and analysis of bHLH transcription factors in

Ginseng ( C.A. Meyer) is one of the best-selling herbal medicines, with ginsenosides as its main pharmacologically active constituents. Although extensive chemical and pharmaceutical studies of these compounds have been performed, genome-wide studies of the basic helix-loop-helix (bHLH) transcription factors of ginseng are still limited. The bHLH transcription factor family is one of the largest transcription factor families found in eukaryotic organisms, and these proteins are involved in a myriad of regulatory processes. In our study, 169 bHLH transcription factor genes were identified in the genome of , and phylogenetic analysis indicated that these PGbHLHs could be classified into 24 subfamilies. A total of 21 RNA-seq data sets, including two sequencing libraries for jasmonate (JA)-responsive and 19 reported libraries for organ-specific expression analyses were constructed. Through a combination of gene-specific expression patterns and chemical contents, 6 PGbHLH genes from 4 subfamilies were revealed to be potentially involved in the regulation of ginsenoside biosynthesis. These 6 PGbHLHs, which had distinct target genes, were further divided into two groups depending on the absence of MYC-N structure. Our results would provide a foundation for understanding the molecular basis and regulatory mechanisms of bHLH transcription factor action in .

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

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 qPCR 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.