## 1 Introduction  
Abiotic stress, such as drought, salinity, and extreme temperatures, has a detrimental impact on plant growth, development, and productivity [1]. Salt stress limits plant growth by disturbing cellular biochemistry and physiology through the excessive production of reactive oxygen species (ROS). The primary forms of ROS include singlet oxygen (\({}^{1}\)O\({}_{2}\)), hydrogen peroxide (H\({}_{2}\)O\({}_{2}\)), and superoxide radical (O\({}_{2}-\)) [2]. Oxidative stress is a secondary stress triggered by salt stress in plants, where salt stress promptly leads to the buildup of harmful ROS and subsequent oxidative damage [3]. Plants have evolved diverse mechanisms to mitigate oxidative stress, including the synthesis of antioxidants and the activation of stress response pathways [4]. Many enzymatic and non-enzymatic antioxidant scavengers help to maintain ROS at suitable levels to avoid toxicity in plants under salt stress. The scavengers of ROS include superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), among others. These enzymes are activated following stress, thereby aiding plants in better coping with adverse environmental conditions [5, 6]. Transcription factors (TFs) are specialized proteins that serve as essential regulators in the precise control of gene expression by binding to specific promoter regions [7]. The MYB family is one of the largest TF families in plants, and many MYB family members have been found to be involved in coping with salt stress in plants. For instance, _SiMYB16_ can enhance plant salt tolerance by regulating the biosynthesis of lignin and suberin [8]. The overexpression of _GmMYB81_ markedly increases seed germination rates and promotes the growth of green seedlings under conditions of salt and drought stress. This suggeststhat _GmMYB81_ has the potential to enhance plant tolerance to salt and drought stress, specifically during seed germination [9]. The overexpression of _AtMYB20_ in _Arabidopsis_ downregulated the expression of _PP2 Cs_, the negative regulators of ABA signaling which encode type 2C serine/threonine protein phosphatases, to help plants adapt to higher salt concentrations [10]. Research has demonstrated that SIMYB102 is involved in scavenging ROS by regulating the activities of enzymatic scavengers and the accumulation of antioxidants in response to salt stress [11]. Salvia miltiorrhiza Bunge, belonging to the Lamiaceae family, is a valuable traditional Chinese medicinal plant species commonly known as Danshen. Bioactive components of Danshen have the effects of anti-oxidation, anti-inflammation, and improving cardiovascular and cerebrovascular diseases. For example, tanshinone IIA can contribute to the treatment of coronary atherosclerotic heart disease (CHD) by reducing myocardial I/R injury. Salvianolic acid B can play a vascular relaxation role in vascular smooth muscle cells by inhibiting Ca\({}^{2+}\) influx [12; 13]. There are two major groups of active pharmaceutical ingredients in Danshen: lipophilic tanshinones (tanshinone I, T-I; tanshinone IIA, T-IIA; cryptotanshinone, CT) and hydrophilic phenolic acids (salvianolic acid B, SalB; rosmarinic acid, RA; caffeic acid, CA) [14]. Given the rising clinical demand for _Salvia miltiorrhiza_, it is imperative to employ innovative metabolic engineering strategies to enhance and improve the biosynthesis of bioactive compounds in this plant. Recently, several MYB transcription factors (TFs) have been identified as regulators of tanshinones and phenolic acid biosynthesis in _Salvia miltiorrhiza_. Typically, overexpression of both _SmMYB9b_[15] and _SmMYB98b_[16] can promote tanshinone concentration in the hairy roots of _Salvia miltiorrhiza_, while _SmMYB11_[17] and _SmMYB2_[18] are both positive regulator of phenolic acid biosynthesis. Studies have shown that some MYB family genes of _Arabidopsis_ can also promote increases in salvianolic acid content in _S. miltiorrhiza.