Transcriptomic analysis of abscisic acid-treated Salvia miltiorrhiza

Phenolic acids and tanshinones are important bioactive components with multiple pharmacological properties accumulated in traditional Chinese medicinal plant Salvia miltiorrhiza. Abscisic acid (ABA) is effective to enhance the content of the two compounds in S.miltiorrhiza, while the regulation mechanism remains unknown. Therefore, deep transcriptome profile of S.miltiorrhiza hairy roots treated with ABA was conducted. Totally, 42,710 unigenes with the average length of 1,157bp were obtained from de novo assembly from about 2.81 billion produced clean reads, of which 27,641 unigenes (64.72%) were successfully annotated. Unigenes encoding key enzymes such as PAL, TAT, C4H, RAS, CYP98A14, GGPPS expressed significantly higher than that in control. Four candidate laccases showing similar expression with RAS and CYP98A14 in phenolic acid biosynthesis were screened out. Four P450 unigenes may be potential tanshinone biosynthesis genes. Furthermore, transcription factor (TF) profiles revealed that 1,250 TFs representing 35 families were identified, of which MYB, AP2/ERF, bHLH and bZIP were most abundant. One MYB member quickly responded to ABA, MJ and YE induction which also expressed in roots was speculated to potentially regulated phenolic acid and tanshinone metabolism. The present study provided a comprehensive transcriptional expression profile affected by ABA, which will help underly the biosynthesis and regulation mechanism.