Study On The Molecular Mechanism Of Different Exogenous Selenium Affecting The Synthesis Of Flavonoids From Ginkgo Biloba Leaves

Flavonoids in Ginkgo biloba leaves have important medicinal value,but under traditional cultivation,the total flavonoid content in Ginkgo biloba leaves is little,which seriously affect the market price of Ginkgo biloba leaves and farmers’income.Therefore,it is significant to study and improve the alternative measures of ginkgo flavonoids.Although the predecessors have made some achievements through cultivation expansion,such as variety selection and other cultivation measures（eg.deal with Inorganic selenium）.But there are still differences in the distance from the production of ginkgo leaves with good quality.The molecular mechanism of the regulation process needs in-depth exploration.This study intends to adopt different exogenous selenium fertilizer treatments to study their effects on the physiological and biochemical indicators of ginkgo and the content of flavonoids in the main active ingredient.Through transcriptome sequencing data,the related genes in the flavonoid metabolic pathways of ginkgo after selenium application were analyzed changes in expression levels are expected to reveal the molecular mechanism of different selenium treatments affecting the content of flavonoids in Ginkgo biloba leaves.The specific research results are as follows.1.In different periods,the effects of different concentrations of biological nano-selenium on the physiological indicators of Ginkgo are different.Bio-nano selenium can improve the chlorophyll content significantly.In July,the 1.6 mmol·L^-1 treatment group had the most significant improvement effect.In September,the soluble sugar content in the 0.4 mmol·L^-1 treatment group reached the highest level,and the difference was significant.In October,the soluble protein content of the 1.6 mmol·L^-1treatment group was the highest among all treatment groups,and the difference was significant.In July,the starch content of the 0.8 mmol·L^-1 treatment group was significant.It is the highest in all cycles and treatment groups,and the substitution difference showed significance.In a word,the biological nano-selenium is the best at the concentration of 1.6mmol·L^-1,which is subdivided,and the indicators have been significantly improved in July and September.2.The effect of different selenium fertilizer treatments on the content of flavonoids in Ginkgo biloba in different periods.Effects on the content of flavonoids in Ginkgo biloba leaves will be different if different selenium fertilizer treatments are used in different time.Compared with the substitution fraction,bio-nano selenium has a significant promoting effect.In July and September,the flavonoid content of the 1.6mmol·L^-1 treatment group was the highest among all groups,which was roughly divided into significant differences.The flavonoid content of the 0.4·mmol L^-1 organic selenium treatment group is the highest in all treatment groups,and the corresponding improvement effect is more than comprehensive.There is a significant difference while the inorganic selenium treatment group showed inhibition.Among the three selenium fertilizer treatment groups,the biological nano selenium is the best,and the best concentration is 1.6 mmol·L^-1.3.The effect of different selenium treatments on the related metabolic genes in the flavonoid synthesis pathway of Ginkgo biloba leaves.Nano selenium,organic selenium,inorganic selenium and various samples with the largest differences were extracted from total RNA,and the results of different selenium treatments on related genes were sent to the test transcriptome.Increased levels;organic selenium promotes the up-regulation of CCR and HCT genes and simultaneously suppresses the expression level of FMO genes;inorganic selenium promotes the up-regulation of C3’H,CCo AOMT,CYP,DFR and HCT genes,and simultaneously improves the down-regulation of BGL and UDP glucose genes The above different selenium treatment groups have different effects on the expression levels of flavonoid-related genes,because the flavonoid content of Ginkgo biloba leaves in different groups is different.The above results indicate that different selenium treatments have different effects on the content of flavonoids in Ginkgo biloba leaves.Among them,nano-selenium treatment increased the flavonoid content of Ginkgo biloba leaves the most,reaching two peaks in July and September respectively,prolonging the batch harvesting time of Ginkgo biloba leaves,and increasing the total annual Ginkgo biloba leaf harvest.biological nano-selenium treatment increased the total chlorophyll content of Ginkgo biloba leaves,and increased the content of starch,soluble sugar,soluble protein,etc..Bio-nano selenium can promote the expression of PAL,COMT,CAD,F6H and other genes in the flavone synthesis pathway,and the level of key genes and enzymes High promotes the increase of total flavonoid content.Therefore,the appropriate concentration of organic selenium and nano selenium can promote the increase of the content of ginkgo flavonoids,which is conducive to the quality improvement of the leaf ginkgo cultivation industry,enhances the competitiveness of domestic ginkgo leaf exports and earns foreign exchange,and also provides a theory for the cultivation of selenium-rich medicinal plants support.