MiR408-SmLAC3 Module Participates in Salvianolic Acid B Synthesis in Salvia miltiorrhiza

Abstract

MicroRNAs (miRNAs) are important regulators of gene expression involved in plant development and abiotic stress responses. Recently, miRNAs have also been reported to be engaged in the regulation of secondary plant metabolism. However, there are few functional studies of miRNAs in medicinal plants. For this study, we obtained Sm-miR408 interference lines to investigate the function of Sm-miR408 in a medicinal model plant (Salvia miltiorrhiza). It was found that inhibiting the expression of Sm-miR408 could increase the content of salvianolic acid B and rosmarinic acid in the roots. The SmLAC3 and Sm-miR408 expression patterns were analyzed by qRT-PCR. A 5’ RLM-RACE assay confirmed that Sm-miR408 targets and negatively regulates SmLAC3. Moreover, the overexpression of SmLAC3 in S. miltiorrhiza promoted the accumulation of salvianolic acids in the roots. Furthermore, the lignin content of the roots in overexpressed SmLAC3 lines was decreased. Taken together, these findings indicated that Sm-miR408 modulates the accumulation of phenolic acids in S. miltiorrhiza by targeting SmLAC3 expression levels.

The Smi-miR858a-SmMYB module regulates tanshinone and phenolic acid biosynthesis in Salvia miltiorrhiza

“…In addition, Zou et al . constructed an amiRNA-mediated miR408-suppressed expression vector to inhibit the expression of Smi-miR408 in S. miltiorrhiza plants [ 60 ]. The results showed that the content of phenolic acids increased in the transgenic lines.…”

“…The results showed that the content of phenolic acids increased in the transgenic lines. Further analysis showed that the regulatory role of Smi-miR408 in phenolic acid biosynthesis was mediated by targeting the transcripts of laccase gene ( SmLAC3 ) gene for cleavage [ 60 ]. In this study, we found that Smi-miR858a played significant regulatory role in the biosynthesis of phenolic acids, tanshinones, and flavonoids through targeting a subset of SmMYB genes.…”

Genome-Wide Identification and Functional Analysis of Salvia miltiorrhiza MicroRNAs Reveal the Negative Regulatory Role of Smi-miR159a in Phenolic Acid Biosynthesis

“…Overexpression of smi-miR396b in S. miltiorrhiza hairy roots led to the repression of salvianolic acid biosynthesis and to the enhancement of tanshinone production through regulating the expression of SmGRF, SmHDT1, and Sm-MYB37/4 genes [34]. Transgenic S. miltiorrhiza lacking smi-miR408 showed increased levels of rosmarinic acid (RA) and salvianolic acid B (SalB) [35]. Overexpression of smi-miR858a caused a significant reduction in tanshinones and phenolic acids, two major classes of bioactive compounds in S. miltiorrhiza [36].…”

The Evolution and Functional Roles of miR408 and Its Targets in Plants

“…A recent study showed that the function loss of miR408 negatively regulated light-dependent seed germination [ 16 ]. Zou et al [ 17 ] proved that the function loss of miR408 positively regulated the synthesis of Salvianolic acid B (SalB) and rosmarinic acid (RA) in Salvia miltiorrhiza . T-DNA insertion mutants of miR408 were used to explore how miR408 influences copper- and iron-dependent metabolism [ 18 ].…”