Genetic Structure Of Oxytropis Ochrocephala L. And The Relationship With Swainsonine And Endophyte

Oxytropis Ochrocephala L.belongs to the genus Oxytropis and is widely distributed in the steppe of northwest and southwest China.Its distribution in China has been expanded year after year,in United States,Oxytropis species were considered as the invasive species.Oxytropis ochrocephalus contains indole dinidine alkaloids-swainsonine,when a large number of livestock consumption of O.ochrocephala will cause poisoning,seriously may death.O.ochrocephala contains endophyte Undifilum oxytropis,and it's secondary metabolites is swainsonine.Therefore,the study of the genetic structure of O.ochrocephala and the relationship between swainsonine and endophyte can provide new methods for curbing the spread and expansion of O.ochrocephala in China.In the first part,the genetic structure and genetic diversity of O.ochrocephala population in China were analyzed by using molecular marker SSR,and the clonal line of O.ochrocephala in China was forecasted.The second part of the study was about using HPLC to analysis the swainsonine in each population.Analysis of endophyte in each population was carried out by real-time quantitative PCR and restriction endonuclease in the third part.In the fourth part,based on the results of the first three experiments,the genetic structure of O.ochrocephala was analyzed,and the correlation between swainsonine and endophyte was analyzed.And this work mainly achieved the following results:1.Based on the microsatellite markers developed by Illumina sequencing,14 pairs of primers with good polymorphism and stable amplification were screened out from 86 pairs of randomly selected primers.The genetic diversity and genetic structure of 33 population of O.ochrocephala in China were analyzed by 14 SSR primers.The observed allele number Na = 13.714,effective number of alleles Ne= 5.232,Shannon index 1.797,observed heterozygosity Ho = 0.464,expected heterozygosity He = 0.762,multiple information content PIC = 0.731,gene flow Nm = 0.592.Above all information of genetic diversity,indicating that the genetic diversity of O.ochrocephala in 14 pairs of SSR primers was at a high level.The results showed that 33 population were divided into two groups.The first cluster included the population of O.ochrocephala in Ningxia,Gansu,Qinghai and Tibet,population from Sichuan area was divided into the second cluster.The geographical distance between GS6 in Luqu County of Gansu Province and SC6 in Ruoergai Region of Sichuan Province was close,and there was a phenomenon of gene interpenetration between the two population.AMOVA analysis showed that the genetic diversity of O.ochrocephala in population was high,accounting for 73.62%,the genetic diversity among population was low,accounting for 26.28%,the differentiation coefficient Fst between population was 0.297,Indicating that the genetic differentiation between population is large,and there is the possibility of genetic drift.There was also a significant correlation between genetic distance and geographic elevation.The genetic distance between the genetic distance and the geographical distance was significantly correlated with geographical distance(r = 0.5226,p<0.001);(r= 0.4242,p<0.001).Using the ecological simulation DIYABC to analyze the colonization routes of O.ochrocephala,the first differentiation of O.ochrocephala in the northern part of China was followed by the differentiation of the population in the central region of Sichuan to the southern Sichuan region.It can be inferred that O.ochrocephala in China were originated in the northern region,and gradually expanded from the northern region to the south.2.The results showed that most of the population in Gansu,Qinghai,Ningxia and Tibet were found to contain swainsonine.The contents of swainsonine in the three population were higher than those in Sichuan in some areas,the content of swainsonine in the population was 0.The SPSS difference analysis showed that there was significant difference in the content of swainsonine between two groups(p = 0.007<0.05).3.The quantitative analysis of Undifilum oxytropis contained in the sample was carried out by using real-time PCR and restriction endonuclease.The endophytic fungus Undifilum oxytropis was detected by agarose gel electrophoresis.The analysis of endophyte content showed that there was no significant difference between the two groups(p= 0.058>0.05).4.The correlation analysis of genetic distance,geographic distance,swainsonine and endophyte showed that there was a significant correlation between swainsonine and endophyte(r=0.356,p=0.042<0.005).The genetic distance was significantly positive correlation with endophyte(r = 0.1801,p=0.036<0.005);and the correlation between the genetic distance and swainsonine is 0.2184(p = 0.001<0.005).Geographical distance and swainsonine also have the positive corrlation(r = 0.2215,p = 0.033<0.005).There was also a significant positive correlation between geographical distance and endophyte(r ?0.3400,p = 0.001<0.005).Based on the above results,we can provide new ideas and methods for prevention and control of O.ochrocephala.In order to control the wide spread of O.ochrocephala in our country,we can start from the origin of O.ochrocephala,and eliminate the genetic diversity of O.ochrocephala in the origin,which can reduce the speed and harm degree of Oxytropis.