Study On The Effect Of Methyl Jasmonate In Celastrol Biosynthesis In The Callus Of Tripterygium Wilfordii Hook.f.

Tripterygium wilfordii also accepted as Tripterygium wilfordii Hook.f.,(TwHf)is a widely-known species in the Traditional Chinese Medicine(TCM).In Mandarin Chinese,'lei gong teng' is its common name,which translates to 'Thunder God Vine.' TwHf is native to southern China,and 'Dian Nan Ben Cao'(Medical plants in Southern Yunnan)recorded its first medical uses.Over 380 metabolites from Tripterygium species have had their structures characterized and their biological activities evaluated,of which 95%are terpenoids.Tripterygium wilfordii is a terpene-producing plant with bioactive compounds being diterpenoids such as triptolide and triterpenoids such as celastrol.These natural products have attracted widespread interest due to their wide range of activities such as anti-inflammatory,immunosuppressive,anti-cystogenesis,and anticancer activities.One major problem in harnessing these secondary metabolites is the fact that they occur in low yields in plants and knowledge regarding their biosynthetic pathways is limited.It is possible to provide an adequate and sustainable supply of these natural products via callus-based culture.In this study,calli from Tripterygium wilfordii leaf explants were the experimental materials for the dissection of the pathways of terpenoids in this plant species.The signal molecule,MJ(Methyl Jasmonate),at the final concentration of 50?M was used to induce the biosynthesis of the terpenoids.As a control,we treated the calli with the same volume of 100%DMSO(v/v).We harvested the MJ-treated calli as well as the control calli after 0,4,12,24,48 and 96 h and measured celastrol concentration by High-Performance Liquid Chromatography(HPLC).Based on the MJ treatment,the effects of the signal molecule,Methyl Jasmonate,on the biosynthesis of celastrol were studied.The main findings of this study were summarized as follows:1.Relative to the stem and root organs,the Tripterygium wilfordii leaf explants were most suitable in callus induction.The root and stem tissues were inefficient due to the vulnerability to fungal and or bacterial contamination.Additionally,it was easier to obtain loose callus in the dark condition than in the light state.2.Celastrol was detected in all the callus tissues,but triptolide was not,suggesting that the callus is a sound system for studies on the celastrol biosynthetic pathway but not triptolide.It was also observed that Methyl jasmonate significantly enhanced celastrol biosynthesis across different time points.The variation in the expression of several known upstream pathway genes matched the celastrol accumulation patterns under the MJ treatment,suggesting that MJ regulated the celastrol biosynthesis mostly at the transcription level.3.Overall,Methyl Jasmonate up-regulated the expression levels of several known genes in the upstream pathway of celastrol,which was consistent with the synthesis characteristics of celastrol in different periods.Our data indicated that MJ is an active signal compound in the stimulation of celastrol biosynthesis.Moreover,this improvement was mostly due to the increase in the expression of its biosynthetic pathway.We will plan to globally monitor the changes of the transcriptome of the callus,which will provide a basis for the dissection of the celastrol pathway,especially its downstream unknown pathway.