Optimization of induction and culture conditions for hairy roots of Salvia miltiorrhiza

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.