Effect of Light on Gene Expression and Shikonin Formation in Cultured Onosma Paniculatum Cells

Abstract

The cell culture in a production medium in the dark is capable of producing a large quantity of shikonin and its derivatives, which were completely inhibited when the cell cultures were irradiated with continuous white light and blue light and partially repressed under continuous red light. The expressions of PAL1, 4CL1, and CYP98A6 were induced under continuous red, blue and white light. Transcript levels of HMGR and LDI2 gradually were decreased in the dark and under continuous red light, while no transcriptional product of LDI2 was detected under blue and white light. C4H2 and LePGT1 genes were constantly expressed irrespective of different light conditions. Among the genes studied, the expression of LDI2 was critical for light-regulated shikonin formation. The inducible expression of PAL1, 4CL1, and CYP98A6 as well as the inhibitory transcription of LDI2 mediated by continuous red light irradiation were likely accounted for the reduced accumulation of shikonin.

Expression analysis of shikonin-biosynthetic genes in response to M9 medium and light in Lithospermum erythrorhizon cell cultures

“…Note The primer sequences for GAPDH, PAL, C4H, 4CL, HMGR, PGT, CYP98A6, and LeDI-2 genes were derived from the previous report (Tabata et al 1974;Heide et al 1989;Gaisser and Heide 1996;Liu et al 2006) Plant Cell Tiss Organ Cult (2010) 101:135-142 137 cells increased with time and reached a value of 33.5 mg/g fresh weight (FW) at the end of the culture period (days 10). However, when cultured under white light after inoculation, the cells did not produce shikonin and its derivatives over 10 days of culture period, which indicated that their biosynthesis was fully inhibited by white light (Fig.…”

“…Metabolites were extracted from the cells as well as the culture medium in each flask using 50 ml of petrol ether, and measured by 2800 UV/VIS spectrophotometer (Unico, Shanghai, China) at 520 nm. Total amounts of these metabolites were determined after adjustement to a standard curve (shikonin content = 41.66 9 OD 520 9 dilution fold), and reported in mg/g cell fresh weight (FW) (Liu et al 2006).…”

“…1). Moreover, various biotic and abiotic factors, such as fungal elicitors (Tani et al 1992), plant hormones (Yazaki et al 1997b;Yang et al 1999;Touno et al 2005), and light signals (Tabata et al 1974;Heide et al 1989;Gaisser and Heide 1996;Liu et al 2006), have been investigated to study the molecular mechanism of biosynthesis of shikonin and its derivatives. Previously, methyl jasmonate (MeJA), a plant growth regulator known to stimulate the formation of shikonin and its derivatives, has been reported to strongly up-regulate the expression of PGT and CYP98A6 (Matsuno et al 2002;Yazaki et al 2002).…”

Spectral composition of irradiation regulates the cell growth and flavonoids biosynthesis in callus cultures of Saussurea medusa Maxim

“…It is known that upon absorption of a photon of light, phytochrome is converted to the active farred-absorbing Pfr form, which regulates the gene expression leading to relevant photoresponeses, including cell division and tissue growth with primary and secondary metabolites (Smith 2000;Liu et al 2006). The conversion of red-absorbing Pr Table 2 form to Pfr form is more under blue light than that under red light.…”

Enhanced production of antitumour naphthoquinones in transgenic hairy root lines of Lithospermum canescens

“…However, there have been still conducted investigations to reveal factors influencing its biosynthesis (Zou et al 2011;Zhang et al 2010;Liu et al 2006) and to enhance shikonin/alkanin and their derivatives production (Zare et al 2010).…”