The Effects Of Different Light Qualities On The Accumulation Of Gypenoside And The Gene Expression Of Key Enzymes Related To The Biosynthesis Of Gypenoside In Gynostemma Pentaphyllum

To explore the effects of Light quality on gypenoside anabolism, the seed germination cultivating seedlings of Gynostemma pentaphyllum were taken as materials in this experiment. Setting up four kinds of light processing: the red(650 + 20 nm),the blue(470 + 20 nm), the white(control group) LED light and the dark. We deal G.pentaphyllum plants with different light for 1-4 days, to measure the influence of light quality on gypenoside accumulation and the gene expression of Squalene Synthase(SS) and Squalene Epoxidase(SE), the results are showed as follows:1. Compared with white light(control groop), the red and blue light is good for gypenoside accumulation, the red light is more advantageous than blue light on gypenoside accumulation, under the condition of darkness, it inhibits gypenoside accumulation. Under the four different light processing, the high and low order of gypenoside accumulation as: Red light > Blue light > White light > Dark. Under the white light processing for 1-4 days, the content of gypenoside have no significant difference, the average is 2.36%; Under the red light processing, the second day of saponin content up to 5.34%, increased by 3.02% compared with under the white light, the saponin content of high and low order at 1-4 days as: Red(2) > Red(1 d) >Red(3 d) > Red(4 d); Under the blue light conditions, the third day saponin content up to 3.90%, increased by 1.54% than the control group, the saponin content of high and low order at 1-4 days as: Blue(3 d) > Blue(2 d) > Blue(1 d) > Blue(4 d); Under dark conditions, the first day of saponin content is higher at 1.94% relative to other three days, decreased by 0.23% than the control group, the saponin content of high and low order at 1-4 days as: Dark(1 d) > Dark(2 d) > Dark(3 d) > Dark(4 d).2. Compared with white light(control group), red and blue light are conducive to the gene expression of Squalene Synthase(SS) and Squalene Epoxidase(SE),and dark conditions inhibit the gene expression of Squalene Synthase(SS) and Squalene Epoxidase(SE). In a word, in four different illumination conditions, the gene expression level of Squalene Synthase(SS) and Squalene Epoxidase(SE) according to high and low order as: Red light > Blue light > White light > Dark. under the white light at 1-4 days, the gene expression level of SS and SE have no significant difference. This experiment take white light as a control group, the initial templaterelative of Squalene Synthase(SS) and Squalene Epoxidase(SE) to the sample quantity is 1; Under the condition of Red light treatment, the second day of gene expression level of Squalene Synthase(SS) and Squalene Epoxidase(SE) is the highest, Relative sample quantity ofinitial template of SS is 11.08, Relative sample quantity of initial template of SE is11.06, under different time at 1-4 days, the gene expression level of Squalene Synthase(SS) and Squalene Epoxidase(SE) according to high and low order as: Red(2d) > Red(1 d) > Red(3 d) > Red(4 d); Under the condition of the Blue light treatment,the third day of gene expression level of Squalene Synthase(SS) and Squalene Epoxidase(SE) is the highest, Relative sample quantity of initial template of SS is4.23, Relative sample quantity of initial template of SE is 3.94, under different time at 1-4 days, the gene expression level of Squalene Synthase(SS) and Squalene Epoxidase(SE) according to high and low order as: Blue(3 d) > Blue(2 d) > Blue(1d) > Blue(4 d); Under the condition of Dark treatment, with the increase of time, the level of gene expression of Squalene Synthase(SS) and Squalene Epoxidase(SE)gradually reduce, the first day of the samples relative amount of initial template of SS is 0.27, the relative sample initial template of SE is 0.15, under different time at 1-4days,the gene expression level of Squalene Synthase(SS) and Squalene Epoxidase(SE)according to high and low order as: Dark(1 d) > Dark(2 d) > Dark(3 d) > Dark(4 d).3. According to correlation analysis of the content of gypenoside accumulation and Squalene Synthase(SS), Squalene Epoxidase(SE) gene expression level,we find that red, blue, white light and dark have Positive correlation effects on the content of gypenoside accumulation and the G.pentaphylla SS and SE gene expression levels.While G.pentaphylla SS and SE gene expression level is high, the content of gypenoside is high, and when G.pentaphylla SS and SE gene expression level is low,the content of gypenoside is low. So we speculate that light quality can adjust the Squalene Synthase(SS) and Squalene Epoxidase(SE) gene expression, which affects the gypenoside accumulation, the higher the G.pentaphylla SS and SE gene expression level, the higher the gypenoside content.