Abstract
Salvianolic acids, a group of secondary metabolites produced by Salvia miltiorrhiza, are widely used for treating cerebrovascular diseases. Copper is recognized as a necessary microelement and plays an essential role in plant growth. At present, the effect of copper on the biosynthesis of SalAs is unknown. Here, an integrated metabolomic and transcriptomic approach, coupled with biochemical analyses, was employed to dissect the mechanisms by which copper ions induced the biosynthesis of SalAs. In this study, we identified that a low concentration (5 μM) of copper ions could promote growth of S. miltiorrhiza and the biosynthesis of SalAs. Results of the metabolomics analysis showed that 160 metabolites (90 increased and 70 decreased) were significantly changed in S. miltiorrhiza treated with low concentration of copper ions. The differential metabolites were mainly involved in amino acid metabolism, the pentose phosphate pathway, and carbon fixation in photosynthetic organisms. The contents of chlorophyll a, chlorophyll b, and total chlorophyll were significantly increased in leaves of low concentration of copper-treated S. miltiorrhiza plants. Importantly, core SalA biosynthetic genes (laccases and rosmarinic acid synthase), SalA biosynthesis-related transcription factors (MYBs and zinc finger CCCH domain-containing protein 33), and chloroplast proteins-encoding genes (blue copper protein and chlorophyll-binding protein) were upregulated in the treated samples as indicated by a comprehensive transcriptomic analysis. Bioinformatics and enzyme activity analyses showed that laccase 20 contained copper-binding motifs, and its activity in low concentration of copper ions-treated S. miltiorrhiza was much higher than that in the control. Our results demonstrate that enhancement of copper ions of the accumulation of SalAs might be through regulating laccase 20, MYBs, and zinc finger transcription factors, and photosynthetic genes.
Highlights
Copper, a necessary microelement in plants, plays an essential role in various physiological activities during plant growth and development, such as cell wall metabolism, hormone signaling, photosynthesis, and redox reactions (Choudhary et al, 2012; De Caroli et al, 2020; Ding et al, 2020; Saleem et al, 2020)
To ascertain the most suitable concentration of copper that promotes salvanoic acids (SalAs) biosyntheses, we used High-Performance Liquid Chromatography (HPLC) to determine the contents of salvianolic acid B (Sal B) and rosmarinic acid (RA) in the copper-stressed groups and the blank group
We reported that a low concentration of copper (5 μM) could promote the biosynthesis of SalA in S. miltiorrhiza
Summary
A necessary microelement in plants, plays an essential role in various physiological activities during plant growth and development, such as cell wall metabolism, hormone signaling, photosynthesis, and redox reactions (Choudhary et al, 2012; De Caroli et al, 2020; Ding et al, 2020; Saleem et al, 2020). Copper is a redox-active transition metal, and two valence states (Cu2+ and Cu+) exist under physiological conditions. Copper works as a constituent of Cu/Zn-superoxide dismutase (Cu/Zn-SOD), localized in the stroma that protects against reactive oxygen species (Yruela, 2009). Due to these characters, copper ion plays an important role in regulating plant physiology
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
