Studies On The Effects Of Temperature And Immobilization Aspergillus Niger On Ginsenoside Content In Adventitious Root Cultures Of Ginseng

Panax ginseng C.A.Mey is a plant of the genus Panax ginseng,whose roots are valuable Chinese herbal medicines.Ginsenoside is its main active ingredient and has anti-tumor,anti-aging and anti-fatigue effects.In this study,the effects of temperature and immobilized Aspergillus niger on roots growth and ginsenosides accumulation in the adventitious culture of Panax ginseng were studied on the basis of the established culture system of adventitious.At first,this study compared the growth state and ginsenosides accumulation of P.ginseng adventitious roots in different temperature environment and found that different temperature(15,20,25,30?)could affect the growth and differentiation of ginseng adventitious roots.At 15?,the number of differentiation roots reached the maximum,while at 30?,the length of taproot were longest.In addition,we found that low temperature could stimulate the accumulation of ginsenosides,and 10? for 7 days was the best cryogenic treatment conditions,the content of ginsenosides reached 34.10±0.37 mg/g,was 2.4 times of control group(25?).In addition,the transcriptional levels the functional genes and PgWRKYs in the ginsenosides biosythnthesis pathway were also analyzed.Correlation analisis showed that GPS,SS,CYP716A47,CYP716A53v2,UGT94Q2,PgWRKY1,PgWRKY3 and PgWRKY8 were significantly correlated with total ginsenosides.Transcriptome data analysis of 25? and 10? processing ginseng adventitious roots found out five potential transcription factors associated with ginseng saponin synthesis,through correlation analysis,found the Cluster-3045.22385 correlation is best,and speculated that its through regulating FPS,SS gene expression,eventually control the content of ginsenosides.The effects of A.niger crude extracts,immobilized mycelium and spores on ginsenosides accumulation were investigated.Among them,the optimal inducer was the immobilized A.niger spore suspension.The optimal effect was obtained at the spore concentration of 102 spores/mL,the volume ratio of 4%and the co-culture time of 24 h.The total ginsenoside content reached 26.43±0.49 mg/g,3.09 times higher than the control group.The fermented liquid ingredients were tested,and lactic acid were only detected in the treatment group.Lactic acid could promote the accumulation of ginsenosides,and when the lactic acid concentration of 20 mg/L,the content of ginsenosides reached maximum(19.66±0.16 mg/g),was 2.38 times that of the control group.Lactic acid could trigger the instantaneous accumulation of signaling molecules and enhance the expression of transcription factors and defense genes,thus resulting in the up-regulated expression of functional genes involved in ginsenosides biosynthetic pathway.These studies laid a theroretical foundation for the large-scale cultivation of P.ginseng adventitious roots and the industrial production of ginsenosides.