Relationship Between Secondary Metabolites Of Artemisia Annua L.and Environmental Regulators

Plant secondary metabolites,as an integral part of plant metabolism and growth,can be mainly divided into three categories: terpenoids,phenolics and nitrogenous organics,all of which have a wide range of pharmacological activities.Artemisinin of the secondary metabolites in Artemisia annua L.is currently the only high-efficiency,low-toxic antimalarial drug,in addition to many other secondary metabolites that can be used as medicine.The accumulation of medicinal secondary metabolites is affected by various environmental factors such as light,water,p H,soil nutrients,enzyme activities,soil microorganisms,and so on.In order to explore the relationship between secondary metabolites and soil environmental factors,this article that,taking the A.annua as the research object,the correlations between secondary metabolites and soil environmental factors were investigated through The accumulation of medicinal secondary metabolites of A.annua,soil characteristics and soil microbes were analyzed from five areas including Weining County(WN),Tianzhu County(TZ),Huangping County(HP),Kaiyang County(KY),Dafang County(DF).The main results are as follows:1.Content sof secondary metabolites of A.annuaThe contents of mainly medicinal secondary metabolites of A.annua were different.The contents of secondary metabolites followed by total polyphenols,artemisinin,scopoletin,chrysosplenol-D,and chrysosplenetin.The contents of the secondary metabolites were different in different areas,the accumulations of total polyphenol,scopoletin,chrysosplenol-D,chrysosplenetin,and artemisinin ranged from 1.27 to 3.44,0.16 to 2.09,0.16 to 0.86,0.10 to 0.46,and 0.25 to 4.26 g/kg,respectively.It indicates that the contents of medicinal secondary metabolites from different sources is different,which leads to differences in the efficacy of medicinal materials.There was a significant correlation between some secondary metabolites.For example,except artemisinin,total polyphenols were significantly associated with scopoletin,chrysosplenol-D,and chrysosplenetin(P<0.05);the scopoletin was extremely significantly correlated with chrysosplenetin and artemisinin(P<0.01),and significantly associated with chrysosplenol-D(P<0.05);There were extremely significant correlattion between chrysosplenol-D and chrysosplenetin,artemisinin(P<0.01),and chrysosplenetin was significantly correlated with artemisinin(P<0.01).there were significant correlations between them due to a common biosynthetic pathway between some of the medicinal ingredients.2.Soil nutrient and enzyme activity of Artemisia annuaThe soil nutrient content and soil enzyme activity of A.angustifolia are different.From the aspect of soil nutrient,the soil nutrient content of Huangping County and Dafang County is higher,while the soil nutrients in Tianzhu County and Weining County are more scarce.The soil enzyme activities of Huangping County and Kaiyang County were higher than those of the other three plots,while the soil enzyme activity in Tianzhu County was lowest,indicating that A.annua had stronger the ecological adaptability growing under the different conditions of the soil environment.Urease activity was extremely significantly correlated with soil total nitrogen,total phosphorus,alkali nitrogen and available potassium(P<0.01).The phosphatase activity was extremely significantly correlated with organic matter,total nitrogen,alkaline nitrogen and available potassium(P<0.01).The activity of invertase was extremely significantly correlated with total nitrogen,alkali nitrogen and available potassium(P<0.01),and significant with organic matter(P<0.05).It indicates that soil enzyme activity is closely related to some soil physical and chemical properties,which is beneficial to promote material decomposition and transformation.3.Rhizosphere soil microbes of A.annuaThe soil microbial diversities of A.annua is different.In terms of soil bacteria and fungi,the number,type and richness of bacteria OTU are significantly higher than that of fungi.For each plot,number,type and richness of OTUs in Kaiyang County and Dafang Conty were higher than the other three plots.Through the beta diversity analysis,the soil microbial community structures in Kaiyang County and Dafang County were similar.The difference of soil microbial community structures between Huangping County and Weining County is the largest.Redundancy analysis showed that the main factors affecting the diversities of bacteria were altitude,total phosphorus,urease activity,total nitrogen,alkali nitrogen,organic carbon,total potassium,etc.,while the diversities of fungi were not significantly affected by environmental factors.It can be seen that soil microbial bacteria are more sensitive than the effects of fungi on environmental factors,and are also important contributors to the transformation of soil materials in the study site,and are also susceptible to soil physical and chemical properties and enzyme activities.4.Correlation between secondary metabolites and soil regulatorsThe accumulation of medicinal secondary metabolites of A.annua was affected by Soil nutrients.The concentrations of scopoletin,chrysosplenol-D,chrysosplenetin,and total polyphenols were significantly positively correlated with total potassium(P<0.05,P<0.01).There were significant negative correlations between the scopoletin,chrysosplenetin and total polyphenols,soil organic matter and total nitrogen(P<0.05,P<0.01).There were significant negative correlations between artemisinin,scopoletin,chrysosplenetin and total polyphenols(P<0.05,P<0.01).The accumulation of secondary metabolites is also dominated by the abundances and diversities of soil microbes,and the correlation with fungi is more closely related to bacteria.Through the factor analysis,it can be concluded that the most important influencing factors affecting the accumulation of secondary metabolites of A.annua are the species and richness of bacteria in rhizosphere soil microorganisms.The mainly factors are the alkaline nitrogen,total nitrogen and organic matter,secondary factors are the richness and diversities of soil fungi,as well as urease and soil total phosphorus.