Population Genetics Of The Endangered Species Opisthopapus Shih

Opisthopapus Shih is a perennial herb,and only grow in Taihang Mountains of China,only containing the two species Opisthopappus taihangensis Shih and Opisthopappus longilobus Shih.The genus is rich in aromatic oil and fragrance lasted after dry,with high economic and ornamental value.Due to a narrow distribution range,unique ecological environment and significant manufactured picking,Opisthopappus Shih has been listed as a Class II State-Protected Endangered Plant Species.This paper used SSR?Simple Sequence Repeat?and nSSR?Nuclear Simple Sequence Repeat?marker combined with ecological niche modeling?ENM?,analyze the genetic differentiation pattern and reasons.In additional,the study infered refugia in Quaternary glaciation,reveals the evolutionary history,predict the distributon areas in the future and influence environmental factors as its protection theoretical basis and reference.The main results are as follows:1.According to the transcriptional datas,we designed 63 pairs of SSR primers,11 primers with stable results were screened among them.There were 416 polymorphic loci among 424 amplification sites,and the ratio of polymorphic loci?PPB?was 98.11%.Among the 11 pairs of primers,primer 10 had the highest genetic diversity and genetic differentiation index(Ht=0.2811,G_ST=0.3906).In all populations,the highest genetic diversity was HDX population?I=0.3522?,and the BXT population was the lowest?I=0.0544?.The genetic variation within populations?66%?is higher than that among populations?34%?,which is consistent with the genetic differentiation coefficient(G_ST=0.3752),indicating that genetic variation is mainly derived from within populations,and there is a certain genetic communication among populations.The 19 populations were divided into three branches,and the Opisthopappus longilobus populations distributed in Hebei?WDS,JNH,BXT?were a independent branche,and the genetic exchanges between Shanxi and Henan populations were frequent.There exist a certain correlation between genetic distance and geographical distance?r=0.1030,P<0.05?.The blast protein encoded by transcript sequence of primer 9 and primer 11 is PI3K,which related to seed germination and cell apoptosis.It may affect the population differentiation of Opisthopapus Shih by temperature and precipitation.The transcriptional factor AaMIXTA1 corresponding to primer 1 and DEAD-box ATP-dependent RNA helicases corresponding to primers 4 and 8,may play a regulatory role in its resistance to the reverse process.2.According to the literature,30 pairs of nSSR primers were searched and designed,and 12 primers with stable result were selected.98 amplification loci were counted,including 97 polymorphic loci,and the polymorphic loci ratio?PPB?was98.98%.The genetic diversity and genetic differentiation index of primer 8 were the highest(Ht=0.4099,G_ST=0.5191);all of the populations,the population GS had highest genetic diversity?I=0.4130?,WWS was the lowest?I=0.1222?.The genetic variation within the populations?57%?was higher than that among the populations?43%?,and was consistent with the genetic differentiation coefficient(G_ST=0.4466).All the populations were divided into three,the result was basically the same as the result of SSR,support geographical distance played a certain role in the genetic structure?r=0.0982,P<0.05?.3.Based on 44 distribution points of Opisthopapus Shih,niche simulation analysis was carried out.Principal component analysis?PCA?and maximum entropy model?MAXENT?determined 6 key variables?bio 2,bio 3,bio 6,bio 8,bio 11,bio 13?.During the LIG,distribution areas of the genus extended westward;in LGM,the distribution areas of southern and western in China decreased sharply;the distribution habitat in MH consistent with the contemporary.Opisthopapus Shih formed refugia in Quaternary glaciation and until ro 2070,the distribution areas reduced and migrated to east,mainly in Shanxi,Henan and Hebei where located in the Taihang Mountains.The results of niche identity test showed that O.taihangensis and O.longilobus occupied different niches.4.The two-tailed t-test results of niche identity test showed that O. taihangensis and O.longilobus occupied different niches.Environmental factors are significantly different in these two species,including bio 7,bio 14,bio 15,bio 17 and bio 19.The genetic parameters of O.taihangensis mainly related to the environmental factors bio 4,bio 7,bio 14,bio 15,bio 17,and bio 19.The results of O.longilobus mainly relates to bio 4,bio 7,bio 15.In summary,the environmental factors affecting the genetic diversity and niche of the two species are similar.It is the different niches between these two species that make them use different environmental resources,which ultimately leads to genetic differences between the two species.