Comparative Study On Metabolic Components And Transcription Regulation Of Cordyceps Militaris Under Two Cultivation Conditions

Cordyceps militaris is an important edible and medical fungus with high economic and social value,which has formed a good basis for artificial cultivation and industrialization.In recent years,research on Cordyceps militaris has been deepened and a series of research results have been obtained.However,there are relatively few studies on the dynamic changes of genes and metabolic components during the cultivation of Cordyceps militaris;and the use of yew extract,which has the same anti-cancer activity,for the fermentation of Cordyceps militaris to test for new medicinal properties is rarely reported.In this study,two media,PDA and yew extract,were used to culture Cordyceps militaris in darkness for 150 days.Mycelia,which were cultivated for different periods in two media,were performed transcriptome sequencing and detected major functional components.The major findings were as following:In order to compare the growth curve and the variation of functional components of Cordyceps militaris under two different media,the mycelia were measured at different times to determine the biomass,polysaccharides,cordycepic acid,total saponins,flavonoids,adenosine,cordycepin,and ergosterol.The content of paclitaxel in the mycelia and medium was also measured.The results showed that mycelia's biomass under both media showed a trend of rise first and then kept stable.The content of polysaccharides in the PDA group varied greatly during the culture period;the content of flavonoids and total saponins were stable within a relatively high range during the stable growth of the mycelia;adenosine and cordycium acid content decreased sharply during the initial period of culture;the content of cordycepin increased first and slowly decline in the later period;but the ergosterol increased continuously.Cordyceps militaris cultured by extracts showed that the growth was lagging,the content of cordycepic acid and adenosine increased,polysaccharides and cordycepin reduced,and no detectable paclitaxel in mycelia,the content of paclitaxel in medium was not change significantly.Relatively speaking,PDA is more suitable for the culture of Cordyceps militaris,and the optimal culture time is 40~45 d.The optimum time of the Cordyceps militaris cultivated by the extract is about 30 days.The mycelia of 10 d,20 d,45 d in PDA group,and the mycelia of 20 d,45 d,110 d in extact group,were selected for transcriptome sequencing.The differentially expressed genes(DEGs)with different expression patterns were selected for GO and KEGG enrichment analysis.The results showed that Cordyceps militaris gradually enhanced the synthesis of proteins during the culture process,but weakened the membrane transport and synthesis at the later stage.After 110 days of extract culture,the degradation of amino acids and aromatic compounds was evident.At the same time,the DEGs whose expression levels were up-regulated in both media were screened,including one suspected of being associated with muramidase.The expression of the genes,Cns1 and Cns2,which are related to cordycepin synthesis,increased first and then decreased in PDA culture,but they were decreased in the extract medium.That is,their expression levels were highest at 20 days.The ergosterol synthesis-related genes(gene clusters)were actively expressed at 20 days under both culture conditions.Then,the transcriptome results were confirmed to be reliable by fluorescence quantitative PCR.Using mycelia PDA culture for 10 days as a control,the DEGs at 20 days and 45 days of PDA culture were compared with that at 20 d,45 d and 110 d of extract culture.The effects of adding extract on the Cordyceps militaris were analysed by GO and KEGG enrichment analysis.The research findings showed that after the addition of yew extract,the response of Cordyceps militaris to protein synthesis was weakened,and the metabolize of fatty acid,sugar and selenium were affected,the gene controlling the synthesis of coenzyme Q6 also increased its expression,inferred that the content of coenzyme Q6 may have changed.In this paper,we analyzed the differences of gene expression in the Cordyceps militaris,which was cultured in the artificial environment.The differences in biosynthesis and energy transfer caused by the dynamic changes in different periods were clarified,which provided a reference for the later purposeful development and utilization of single components of Cordyceps militaris.At the same time,the transcriptome differences of Cordyceps militaris with yew extract were obtained,which provided data support for the joint culture of the two species,moreover,it provided a valuable example for discussing the use of supplementary materials with medicinal ingredients to cultivate Cordyceps militaris and further exploring new medicinal values.