RESULTS
SmGRAS5 and tanshinones are co-located in the periderm ofS. miltiorrhiza roots
To study the functions of SmGRAS5 gene, the coding regions were amplified by using root-derived cDNAs from S. miltiorrhiza .SmGRAS5 contains an open reading frame (ORF) encoding 335 amino acids. The amino acid sequences of SmGRAS5 contained the conserved GRAS domain. The phylogenetic analysis indicated that SmGRAS5 belongs to SCL3 subfamily (Fig. S1).
Since the medicinal part of S. miltiorrhiza is the roots and the tanshinones were mainly accumulated in the roots, the potential functions of SmGRAS5 in tanshinones biosynthesis were detected by analyzing its expression patterns in the periderm, phloem and xylem tissues ofS. miltiorrhiza roots. The expression levels of SmGRAS5were the highest in the periderm, suggesting the important roles ofSmGRAS5 in the periderm (Fig. 1A). In addition, the four contents of tanshinones (DT-I, CT, T-I and T-IIA) were also detected in the three tissues of the roots. Tanshinones were mainly concentrated in the periderm (Fig. 1B). The results showed SmGRAS5 to be co-located with tanshinones in the periderm (Fig. 1C). Therefore, we speculated that SmGRAS5 might be involved in the regulation of tanshinones biosynthesis.