Population Genomics Study Of The Relict Plant Reaumuria Trigyna In Eastern Alxa-western Ordos

The relict plant,Reaumuria trigyna,is endemic to the Eastern Alxa-Western Ordos desert area.It may have developed a unique survival strategy during the long-term adaptation to its harsh habitats.By using restriction-site associated DNA sequence(RAD-seq)technology,and combining the transcriptomic data of R.trigyna,the present study performed population genomics of the species and investigated the genetic diversity,population genetic structure,and local adaptation of this species.The results provide a novel scientific basis for exploring the stress adaptation mechanism and the endemic genetic resources of R.trigyna,and provide a reference for carrying out relevant studies of other plant resources in this region.The main results are as follows:(1)The soil salinity analysis of eight R.trigyna populations showed that the plant can grow and complete its life cycle in non-saline,lightly saline,heavily saline,and saline soils,where the soil composition is dominated by Na₂SO₄ and Ca SO₄.(2)By using RAD-seq technology,a total of 161.21 Gb genome sequence data were obtained,and identified 96,232 high-quality SNPs.(3)92,719 neutral SNPs were used for the population genetic study of R.trigyna.The results showed that R.trigyna processes a low level of genetic diversity,and with mean H_E?H_O?PIC,and?was 0.208,0.249,0.176,and 0.223,respectively.(4)Population genetic structure analysis showed that the eight R.trigyna populations could be divided into five subpopulations.But the degree of genetic differentiation between populations was low,with an average F_ST of 0.043.Migrate analysis indicated that the gene flow between R.trigyna populations might be a north-to-south pattern.(5)A total of 3513 outlier SNPs were identified,and their corresponding RAD-tags were mapped to 243 transcripts in the R.trigyna transcriptome.Gene ontology(GO)functional annotation showed that these transcripts were distributed in GO terms of"metabolic process","cell",and"catalytic activity"etc.,and KEGG pathways of"metabolic pathways","biosynthesis of secondary metabolites",etc.(6)Thirty-two SNPs were genotyped,thirteen of which were polymorphic in 60individuals of eight R.trigyna populations,and the remaining nineteen were homozygotes or heterozygous in all investigated individuals.Four of 19 genes were associated with flavonoid synthesis and signal transmembrane transduction.