## 2 Results and Discussion
### Analysis of Expression Profile of Pc-fps and Total Triterpenoids at Different Stages of Development  
The transcriptional level of _Pc-fps_ at different stages of development was determined by real-time quantitative PCR. As shown in Figure 7, gene expression was relatively low in 5-to-15-day-old mycelia. However, the expression level was increased after 20-to-30-day-old mycelia. The fruiting  
Figure 5: SDS-PAGE analysis of culture supernatant and purified rPc-FPS. Lane **M**: molecular mass marker; lane **1**: culture supernatant from mock transformant _P. pastoris_ X33 containing expression vector pPICZ_a_A (negative control); lane **2**: culture supernatant culture supernatant from transformant _P. pastoris_ X33 containing expression vector pPICZ_a_A_-fps_; lane **3**: purified rPc-FPS. Figure 6: GC detection of the catalyzed product of the recombinant enzyme encoded by _Pc-fps_. (a) authentic FPP-derived farnesol; (b) the sample extracted from an _in vitro_ reaction mixture containing the purified rPc-FPS; (c) The sample extracted from an _in vitro_ reaction mixture containing the product from a mock purification scheme of mock transformant _P. pastoris_ X33 containing expression vector pPICZ_a_A. process increased the expression level of _Pc-fps_. In the primordia, the expression level of _Pc-fps_ was 9-fold higher than that of _Pc-fps_ in the 5-day old mycelia. The content of total triterpenoids under different stages of development is shown in Figure 8. As shown in Figure 8, the content of total triterpenoids was relatively low in 5-to-15-day-old mycelia and increased gradually after 20-to-30-day-old mycelia. The content of total triterpenoids of primordia was 3.31 mg/100 mg, which was 1.8-fold higher than the 30-day-old mycelia (1.83 mg/100 mg). FPS as a key enzyme in triterpenoids biosynthesis and the activity of FPS may influence the amount of triterpenoids produced in _P. cocos_. In this study, we analyzed the expression profile of _Pc-fps_ and content of total triterpenoids under different stages of development. The results showed that there is a positive correlation between the expression level of _Pc-fps_ and the amount of total triterpenoids produced in _P. cocos_. During the 5-to-15-day-old mycelia, the expression level of _Pc-fps_ and total triterpenoids content were relatively low. However, the expression level and total triterpenoids content were increased gradually after 20-to-30-day-old mycelia. During all different stages of development, the expression level and total triterpenoids content of primordia were higher than other stages. Figure 8: Analysis of the content of total triterpenoids in _P. cocos_ at various developmental stages. (a) 5-day-old mycelium; (b) 10-day-old mycelium; (c) 15-day-old mycelium; (d) 20-day-old mycelium; (e) 30-day-old mycelium; (f) primordia. Figure 7: Analysis of expression levels of _Pc-fps_ in _P. cocos_ at various developmental stages. (a) 5-day-old mycelium; (b) 10-day-old mycelium; (c) 15-day-old mycelium; (d) 20-day-old mycelium; (e) 30-day-old mycelium; (f) primordia. Analysis of Expression Profile of Pc-fps and Content of Triterpenoids under Methyl Jasmonate (MeJA) Treatments  
The effects of MeJA induction on expression profile of _Pc-fps_ and content of total triterpenoids in _P. cocos_ is shown in Figure 9. The results shown in Figure 9a indicate that there is a significant difference in total triterpenoids production between the control and experimental groups demonstrating that MeJA can potentially stimulate triterpenoids biosynthesis. The total triterpenoids content increased from 2.11 to 3.21 mg/100 mg, from 2.68 to 3.63 mg/100 mg and from 2.47 to 3.31 mg/100 mg when MeJA concentrations were 100, 200 and 300 \(\upmu\)M, respectively. The total triterpenoids content was approximately 3.16-fold higher than the control sample when the concentration of MeJA was 200 \(\upmu\)M and the induction time was 72 h. Figure 9b shows the results of RT-PCR analysis of expression level of _Pc-fps_ treated with different concentrations of MeJA.