Genetic Diversity Analysis Of Limonium Bicolor Based On SSR Technology In The Yellow River Delta

Limonium bicolor（Bag.）Kuntze,belongs to the Limonium Mill.plant of Plumbaginaceae.Limonium bicolor is a typical halophyte,and has a very high medicinal value,ecological value,ornamental value,and economic value.Previous studies on this species have been studied,but little research has been done on its genetic diversity.In order to explore the genetic diversity and its genesis of Limonium bicolor in the saline habitats of the Yellow River Delta,the degree of genetic differentiation of the population of Limonium bicolor and the formation mechanism of the genetic structure were studied.Resource protection provides scientific basis.In this paper,202 experimental materials collected from 12 populations collected in the Yellow River Delta region were studied by fluorescent SSR molecular marker technology.SSR markers,also known as microsatellite markers,are tandem repeats consisting of 2-6 nucleotides,which are relatively conserved at both ends.The specific primers were designed according to the sequence of the two ends,and the microsatellite DNA sequence was amplified by PCR technology,and the polymorphism of the length was obtained by polyacrylamide gel electrophoresis or capillary electrophoresis.SSR molecular marker technology has many advantages,co-dominant inheritance,good reproducibility,abundant sites and high polymorphism.Combined with fluorescent labeling technology,it has high intelligence and high work efficiency,enabling rapid collection and processing of data.Finally,through the GENAIEX6.502 software,ARLEQUINv.3.5 software,STRUCTUREv2.3.4 and other professional biological software analysis of experimental results,the following important conclusions are drawn:1.Through screening,18 pairs of polymorphic SSR primer sequences were obtained,which could provide reference for molecular markers of related species.2.The genetic diversity of the population of Limonium bicolor in the Yellow River Delta is higher,the average number of alleles（N_a）is 4.644,the number of effective alleles（N_e）is 2.729,and the average expected heterozygosity（H_e）is 0.529.The Shannon Diversity Information Index（I）is 1.037.3.The genetic differentiation of the Limonium bicolor population is moderate.The F_STindex was 0.067,indicating 6.7%genetic differentiation between populations and 93.3%genetic differentiation within the population.This indicates that there is little difference between the populations of Limonium bicolor,and the difference mainly comes from the inside of the population.The gene flow N_m>4 indicates that the larger gene flow is effective for genetic drift,frequent exchanges between populations,and high degree of similarity between groups.4.Principal component analysis,Mantel-test test,UPGMA cluster analysis and Bayesian cluster analysis of the genetic structure of Limonium bicolor were conducted.The results showed that the genetic distance and the geographical distance of Limonium bicolor were not related to soil salinity difference and geographical location.There was no significant correlation between soil salinity differences and genetic distance.The 12 populations of Limonium bicolor can not be clearly grouped.Analysis of the genetic diversity of Limonium bicolor and the possible causes of population genetic differentiation and genetic structure:The Yellow River Delta is a vast alluvial plain located in the middle of the Bohai Bay surrounded by the Shandong Peninsula and the Liaodong Peninsula.The Yellow River has unique water and sand conditions and a weak dynamic environment in the Bohai Sea.The wind action makes the pollen spread farther away.Coupled with the large number of tributaries here,the seeds drift to other places and promote genetic communication among the population.Within the population,the Limonium bicolor is self-incompatible and increases genetic variation.This study lays a foundation for the study of genetic diversity of Limonium,and provides a scientific basis for the protection of Limonium bicolor.