Cloning and Expression Analysis of SmMYC2, a bHLH Transcription Factor Gene from Salvia miltiorrhiza Bunge

MYC2 is a core transcription factor in the response procedure of jasmonic acid hormones. It plays an important role in regulating plant defense responses, secondary metabolism and growth and development processes. Based on Salvia miltiorrhiza Bunge transcriptomes and genome survey sequences, the MYC2 gene transcription factor in S. miltiorrhiza was cloned and named SmMYC2 (GenBank accession number:KJ945636). The cDNA sequence length of SmMYC2 was 1910 bp with no introns, and the open reading frame (ORF)was 1809 bp, encoding 602 amino acids. Moreover, SmMYC2 contained no membrane-spanning domains or signal peptides, and had high homology with MYC2 of tobacco and tomato. Quantitative real-time PCR analysis showed that SmMYC2 was expressed in the roots, stems, leaves and flowers of S. miltiorrhiza, with the highest levels of expression observed in the roots and stems. In addition, the expression of SmMYC2 could be induced by methyl jasmonate, light and wounding, but could be repressed by gibberellin. The present study will be helpful for further functional research of SmMYC2 in S. miltiorrhiza.