Evaluation Of Medicinal Components Of Specific Germplasm Of Cornus Officinalis And Study On The Molecular Mechanism Of Their Differences

Cornus officinalis Sieb.et Zucc.,a perennial woody plant in Cornus,Cornaceae,is mainly distributed in Qinling mountain of Shaanxi province,Funiu mountain of Henan province and Tianmu mountain of Zhejiang province,as well as in Korea and Japan in Asia.The dried peel of C.officinalis is a traditional Chinese medicinal material with a long history of medicinal use,which has good effects in tonifying the liver and kidney and promoting astriction and stem desertion.Modern pharmacological research shows that the medicinal components of C.officinalis have important biological activities such as liver and kidney protection,nerve protection and antibacterial.Research on C.officinalis mainly was concentrated in the active material separation identification,pharmacological action,evaluation and utilization of resources,etc.And it is lack of the molecular mechanism of medicinal ingredient content differences about different germplasm of C.officinalis.Also,the medicinal ingredient content of fruit in maturation and postharvest shelf life has not been reported.In this study,fruits and leaves of four specific germplasm(No.HN008,HN009,ZJ026 and ZJ030)at different stages were selected as experimental materials,the content of total organic acid was determined using acid-base titration.The content of total CIGs was determined using spectrophotometer.The contents of seven iridoid glycosides,loganin,morroniside,cornoside,sweroside,gallic acid,protocatechuic acid and 5-hydroxymethylfurfural(5-HMF)were determined using high performance liquid chromatography(HPLC).The changes and differences of total organic acid,total CIGs and the above seven iridoid glycosides of the four germplasms were further analyzed.The expression of two key enzyme genes involved in loganin synthesis,G10H(geraniol-10-dehydrogenase)and SLS(secologanin synthase),was determined using quantitative real-time PCR.The molecular mechanism responsible for the differences of the contents of medicinal ingredients between the four germplasm was finally revealed by combing with regression analysis of the contents of loganin and morronisidc.On this basis,the fruits of C.officinalis were stored under 25?,80%RH for 0 d,5 d,1 0 d,1 5 d and 20 d,respectively.The contents of total organic acids,total CIGs and the seven iridoid glycosides was determined.Furthermore,the change and accumulation of medicinal ingredients during the postharvest stage of C oficinalis fruits were revealed.The main results of our study are as follows:1.There were significant differences in contents of total organic acids,total CIGs,morroniside,loganin,comoside,sweroside,gallic acid,protocatechuic acid and 5-HMF in four specific germplasm fruits of C officinalis(P<0.05).Among them,the contents of total organic acid(19.25%)and total CIGs(16.00%)in ZJ030 germplasm were highest,and the contents of morroniside(2.81%),loganin(1.52%)and cornoside(0.32%)in HN009 germplasm were highest.2.There were significant differences about the content of medicinal components in leaves in four specific germplasm of C.officinalis.The results showed that the content of total organic acids in leaves was significantly lower than that in fruits.The content of total organic acid in ZJ030 germplasm was highest(7.75%),in HN008 germplasm was lowest(4.00%).The contents of total CIGs in leaves and fruits were similar,there was no significant difference about the content of total CIGs in four germplasm.Only four kinds of ingredients were detected by HPLC in leaves,which is morroniside,loganin,protocatechuic acid and sweroside,respectively.3.The relative expression of G10H and SLS genes in fruit and leaves of specific germplasm of C.officinalis from July to October were determined.The results showed that:(1)The relative expression of G10H and SLS genes in fruit were higher than those in leaves.(2)The relative expression level of G10H gene in HN009 germplasm was highest(2.398),in HN008 was lowest(0.216),and the expression of the four germplasm were higher in July and August.The relative expression level of SLS gene in HN009 was lowest(0.444),in ZJ030 was highest(0.746).(3)Regression analysis between gene expression and the content of morroniside and loganin was analyzed,which found that G10H gene expression in fruits was significantly positively correlated with the content of morroniside(r=0.5392,P<0.0001),and G10H gene expression in fruits was significantly positively correlated with the content of loganin(r=0.6967,P<0.0001),and SLS gene expression was negatively correlated with the content of loganin(r=-0.1017,P>0.05).There was no significant difference in leaves.4.The content of medicinal ingredients in fruit of C officinalis significantly increased during short-term storage after harvest.The results showed that the content of total organic acids reached the highest value at 15 days after storage,the content of total CIGs increased significantly during the storage,the content of morroniside was the highest at 20 days,and the content of loganin was the highest at 10-15 days,which was significantly different from that on collection day(P<0.05).And then the comprehensive analysis of the content changes of various substances in fruit from Sep.10th to Nov.10th,the best harvest time of C.officinalis was from early September to early October.The evaluation of four specific germplasms of C officinalis and the molecular mechanism of the differences of the content of medicinal components of the four specific germplasm was revealed,which could a scientific foundation for the evaluation,cultivation,breeding of new varieties and comprehensive development and utilization of C.officinalis germplasm resources.