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.