| The medicinal plant Madagascar Periwinkle(Catharanthus roseus) possesses vindoline, catharanthine, vinblastine, and vincristine which play an important role in cancer. However, the contents of the three TIAs in C. roseus leaves are low and the diSTRibution has the specificity of tissue and growth stage. The use of metabolic engineering for improving the centents of the three TIAs in C. roseus leaves has opened up a new way by overexpression of TIAs biosynthesis of key genes. However, Biosynthetic pathway of the three TIAs is very complex, Currently more than 30 catalytic enzymes and transcription factor genes have been cloned. Therefore, Tt is essential to ensure the changes of alkaloids and the key enzymes and transcription factors of TIAs pathway in C. roseus leaves.In this study, we analyzed the contents of the three TIAs by HPLC and the relative expression of the eleven catalytic enzymes and transcription factor genes in C. roseus leaves.The major results are as follows: 1.We discussed the rule of dynamic changes of three alkaloids in C. roseus leaves. The distribution of the three TIAs including vindoline, catharanthine and vinblastine in C. roseus leaves has the specificity of tissue and growth stage. The highest content of vindoline is 1.18 mg/g and the lowest is 0.02 mg/g, a differents of 60 times. The highest content of catharanthine is 2.5 times of the lowest one.2.The expressions of eleven catalytic enzymes and transcription factor genes by the real-time PCR show that the genes containing GGPP,G10H,SLS,D4H,DAT,PRX are the key enzymes genes in TIAs biosynthetic pathway. ORCA3 gene upregulates the expressions of the genes(D4H,DAT,SLS,TDC). |
