ABSTRACT
italic>Salvia miltiorrhiza Bunge is a traditional Chinese medicinal herb widely used to treat cardiovascular and cerebrovascular diseases at clinic. Its main water-soluble components are rosmarinic acid (RA) and salvianolic acid B (SAB), which are produced by phenylpropanoid pathway. 4-Hydroxyphenylpyruvate reductase (HPPR) is a key enzyme in phenylpropanoid metabolism pathway. SmHPPR1 was cloned from S. miltiorrhiza and was constructed into plant expression vector pJR-SmHPPR1. On this basis, SmHPPR1 transgenic Arabidopsis plants were induced and the content of 4-hydroxyphenyllactic acid (pHPL) was determined. SmHPPR1-overexpressing (SmHPPR1-OE) hairy roots of S. miltiorrhiza were obtained and the concentration of active components and transcriptome analysis were performed. The results showed that the concentration of pHPL in SmHPPR1 transgenic Arabidopsis T1 was 0.594 mg·g-1 dry weight. The concentration of RA, SAB and total salvianolic acid in SmHPPR1-OE-3 hairy roots were 1.09, 1.29, 1.15 times of that in control-3, respectively, and the content of Danshensu was 36.26% of that in control-3. Transcriptomic analysis revealed that overexpression of SmHPPR1 caused the upregulation of other phenylpropanoid pathway genes like SmTAT2. Protein-protein interaction indicated CYT (TR74706_c0_g1), NADP+ (TR26565_c0_g1) and NADP+ (TR68771_c0_g1) is the central node of the network and participated in metabolic process and cellular process. The tracking work in this study proved that SmHPPR1 could catalyze the reduction of 4-hydroxyphenylpyruvic acid to 4-hydroxyphenyllactic acid in SmHPPR1 transgenic Arabidopsis, and SmHPPR1-overexpressing in hairy roots of S. miltiorrhiza could increase the concentration of salvianolic acids through synergistically regulating other pathway genes.
ABSTRACT
To establish induction and liquid culture system for hairy roots of Danshen (Salvia miltiorrhiza), Agrobacterium rhizogenes A4, LBA9402, 15834 as test bacterium were used to infect aseptic leaves of Danshen. The hairy roots were induced and positive transgenic hairy roots were selected with PCR using rolB and rolC as the target gene. Then hairy roots of S. miltiorrhiza were harvested and salvianolic acids were extracted with 70% methanol containing 1% formic acid. The content of salvianolic acid B (SalB) and rosmarinic acid (RA) were determined by HPLC. According to the above research results, the Danshen hairy roots induced by A. rhizogenes LBA9402 were inoculated into the following group of culture media: MSOH, MS, B5, and 6,7-V liquid media. Then the same methods of extraction and determination for the content of Danshen hairy roots were adopted. Last, the hairy roots of S. miltiorrhiza induced by A. rhizogenes LBA9402 were inoculated into the MSOH liquid media with different pH values. The content of salvianolic acid were extracted with 70% methanol containing 1% formic acid and determined by HPLC. As a result, three kinds of A. rhizogenes A4, LBA9402, 15834 could induce hairy roots and Ri plasmids were integrated into the genome of S. miltiorrhiza by PCR. Danshen hairy roots induced by A. rhizogenes LBA9402 and A4 produced much more salvianolic acid, which were (3.27 ± 0.37)% [including (1.04 ±0.36)% of RA and (2.22 ± 0.29)% of SalB] and (3.17 ± 0.20)% [including (0.92 ± 0.31)% of RA and (2.25 ± 0.26)% of SalB], respectively. Hairy roots induced by A. rhizogenes LBA9402 when they were cultured in MSOH liquid media produced much more salvianolic acid, which was (4.56 ± 0.36)%, including (1.12 ± 0.26)% of RA and (3.44 ± 0.23)% of SalB. Hairy roots induced by A. rhizogenes LBA9402 produced the most salvianolic acid when they were cultured in MSOH liquid media with the pH value 4.81, which was 4.85%, including 1.16% of RA and 3.69% of SalB. So Danshen hairy roots induced by A. rhizogenes LBA9402 and A4 produced much more salvianolic acid when they were cultured in MSOH liquid media with the pH value 4.81. The research had established the foundation on genetic engineering to improve the quality of S. miltiorrhiza.