1Department of Applied Biology & Chemical Technology, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
2Current address: Institute of Plant Genetics, School of Life Sciences, Huazhong University of Science and Technology, Wuhan, P.R. China
This work was supported financially by the Hong Kong Polytechnic University (G-T431) and the Areas of Excellence Scheme established under the University Grants Committee of the Hong Kong SAR, China (AoE/B-10/2001 and AoE/P-10/2001)
Ag+ was employed as an abiotic elicitor to stimulate the secondary metabolite production in hairy root culture of Salvia miltiorrhiza, a valuable herbal plant. The addition of Ag2S2O3 at 15 - 40 μM to the culture between 12 and 22 days post inoculation resulted in more than 2-fold increase in the yields of the three diterpenoid tanshinones, tanshinone I, tanshinone IIA and cryptotanshinone. This stimulating effect was dependent on the Ag+ dose, the day of Ag+ addition to the culture and the tanshinone species, while the total yield of the three tanshinones (TT) was mainly dependent on the Ag+ dose, with the highest being attained at 30 μM. The Ag+ treatment also caused a dose-dependent inhibition of hairy root growth. Sucrose feeding or medium renewal before the addition of Ag+ to the culture effectively prevented the growth inhibition, and significantly increased the biomass concentration and volumetric tanshinone yield. With combined medium renewal and Ag+ treatment, in particular, the TT yield was increased 6.6-fold relative to that of the control (55.7 mg/L versus 7.3 mg/L). The elicitor function of Ag+ in the hairy root culture was validated by its ability to induce the characteristic elicitor responses of plants, the increase in cross-cell membrane ion fluxes and the production of reactive oxygen species.
5 Threlfall D R, Whitehead I M. The use of metal ions to induce the formation of secondary products in plant tissue cultures. In: Robins RJ, Rhodes MJC, editors Cambridge; Cambridge University Press 1988: pp 51-6
6
Choi H K, Yun J H, Kim S I, Son J S, Kim H R, Kim J H, Choi H J, Hong S S.
Enhanced production of paclitaxel by semi-continuous batch process (SCBP) in suspension culture of Taxus chinensis
.
Enzyme Microb Technol.
2001;
29
583-6
7
Pitta-Alvarez S I, Spollansky T C, Giulietti A M.
The influence of different biotic and abiotic elicitors on the production and profile of tropane alkaloids in hairy root cultures of Brugmansia candida
.
Enzyme Microbial Technol.
2000;
26
252-8
8
Furze J M, Rhodes M JC, Parr A J, Robins R J, Withehead I M, Threlfall D R.
Abiotic factors elicit sesquiterpenoid phytoalexin production but not alkaloid production in transformed root cultures of Datura stramonium
.
Plant Cell Rep.
1991;
10
111-4
9
Wang C, Wu J, Mei X.
Enhancement of taxol production and excretion in Taxus chinensis cell culture by fungal elicitation and medium renewal.
Appl Microbiol Biotechnol.
2001;
55
404-10
12
Chen H, Chen F, Zhang Y L, Song J Y.
Production of lithospermic acid B and rosmarinic acid in hairy root cultures of Salvia miltiorrhiza
.
J Ind Microbiol Biotechnol.
1999;
22
133-8
18
Chen H, Chen F, Chiu F CK, Lo C MY.
The effect of yeast elicitor on the growth and secondary metabolism of hairy root cultures of Salvia miltiorrhiza
.
Enzyme Microbial Technol.
2001;
28
100-5