Phylogeography And Genetic Diversity Of Cynomorium Songaricum

Cynomorium songaricum Rupr is a root-parasitized plant species distributed in the northwest desert and semi desert area of China.In China,the fleshy stems of C.songaricum,with inflorescences removed are a kind of important drugs with tonifying kidney yang,nourishing blood and laxative effect.It is commonly used in Mongolian medicine.Cynomorium songaricum is a well-known achlorophyllous holoparasite medicinal psammophyte,which is usually parasitic on the roots of Nitraria plants in the family Zygophyllaceae.Many reports have indicated that C.songaricum could promote human immune regulation ability,plays important roles in anti-cancer,anti-hypoxia,anti-fatigue,anti-aging,prevention of cardiovascular disease,and anti-stress,and is also used in the scavenging of free radicals.Here,modern molecular biology techniques on DNA level was performed to study the genetic structure of 188 C.songaricum individuals in 18 wild populations,and to explore population genetics status,to analysis the causes of endangerment,providing molecular evidence for the classification system,identification and protection measures of C.songaricum.Analysis of chemical composition was based on the measurements of four chemicals(gallic acid,protocatechuic acid,catechin,and phloridzin contents)using high-performance liquid chromatography(HPLC).High-throught sequencing technology was used for the community compositon and diversity of f C.songaricum,rhizosphere microbiota,and to explore the changes patterens of microbiota community and driving factors.The main conclusions wre as follows:(1)Two mitochondrion genes(ccmFN2 and atpA)were used to detect phylogenetic geographical relationships and genetic diversity of C.songaricum in the northwest region of China.Result showed there is a little difference among total genetic diversity and genetic diversitywithin population,and the numerical coefficient of genetic differentiation among populations was slightly higher(P>0.05,not significant),suggesting there is no obvious pedigree and geographical structure among populaations.And Mantel test showed there is no significant relationship between genetic and geographic distances,AMOVA revealed the variation of C.songaricum mainly occurs in populations,suggesting genetic diversity within populations was significantly higher than that of genetic differences among populations.(2)Using molecular markers,the genetic diversity and structure of C.songaricum from 18 natural populations in the northwest region of China were analyzed based on ITS sequences.Results revealed the variation of C.songaricum mainly occurs in populations.According to ITS sequences,we obtained that the genetic differentiation coefficient NST slightly more than GST(P>0.05,not significant),suggesting there is no obvious pedigree and geographical structure among populaations.And Mantel test showed there is no significant relationship between genetic and geographic distances,indicating that the current distribution of C.songaricum represent is the fragmentation product in recent time.Detection of historical expansion of populations showed that the Tajima’s D test rejected a neutral mutation evolution,and the population expansion history or gene lous is under negative selection pressure,the null hypothesis cannot be ruled out.(3)High-performance liquid chromatographic method was used to the determination of gallic acid,protocatechuic acid,catechin and phloridzin content in C.songaricum.The content of catechin was the highest,followed by gallic acid,and the content of phloridzin was the lowest.At the same time,the simple and feasible fingerprint analysis of C.songaricum was established by methodology,constructing the chemical diversity evaluation system combined fingerprint and quantitative analysis of four main active components.(4)Proteobacteria,Actinobacteria,Euryarchaeota,Bacteroidetes,Firmicutes,Gemmatimonadetes,Nanohaloarchaeota,Acidobacteria,Thaumarchaeota,and Saccharibacteria were the most abundant phyla in the rhizosphere of C.songaricum.There was a significant difference between in C.songaricum rhizosphere soil microbial composition diversity and pH(P<0.05).Variance partitioning canonical correspondence analysis indicated that environmental factors,physicochemical property and chemical composition exerted strong influences on the structure of the rhizosphere microbial community and explained 38.18%and 24.68%of community variances between samples,respectively.Annual precipitation explained most of the variation in the composition of microbial rhizosphere communities of C.songaricum,followed by altitude and pH.Desertification was shown to have complex effects on microbial communities in the northwest of China.