基于重测序的文冠果遗传多样性、群体遗传结构及生态位模拟分析

Xanthoceras sorbifolium is drought tolerant,barren tolerant and adaptable,and is an excellent woody oilseed tree that is mainly grown on the Loess Plateau of China.Due to the long history of cross-introduction,there are major technical bottlenecks in analyzing the genetic diversity and genetic structure of X.sorbifolium resources and their migration routes in the current area of coexistence between cultivated and wild populations based on the nuclear genome.[Objective]In order to understand the genetic diversity and the changes of introduction and migration of X.sorbifolium in the current coexistence pattern of cultivated and wild populations.[Method]The genetic diversity of 215 X.sorbifolium genomes from 17 populations in China is analyzed based on nuclear genome by using genome re sequencing method,and the chloroplast genome sequence of X.sorbifolium was compared based on re sequencing data,the genetic diversity and genetic structure of 172 successfully assembled chloroplast genome SNPs and chloroplast Haplotype of X.sorbifolium were analyzed.Using the PSMC effective population size,we reconstructed the historical dynamics of the distribution and used a species distribution model to reconstruct the potential distribution under the last interglacial,last glacial,mid-Holocene,present and future(2050s)climate scenarios.[Result]The results of genomic research indicate that the average polymorphic information content(PIC)of 17 populations is 0.277,the average aroma index(H)is 0.515,the average diversity index(Nei)is 0.371,the average observed heterozygosity(Ho)is 0.349,and the expected heterozygosity(He)is 0.339,the genetic diversity of X.sorbifolium is at a medium level,the genetic diversity of wild populations is high,and the genetic diversity of cultivated populations is generally low.Sanmenxia in Henan Province is rich in genetic diversity of resources,followed by Ningxia,southern Gansu and western Shaanxi.Structure and NJ phylogenetic trees divide X.sorbifolium population into three groups;The chloroplast genome was divided into four groups.According to the chloroplast genome and Haplotype,it is speculated that there are X.sorbifolium shelters in Linfen,Shanxi and southern Ningxia.The results of SDM Ecological niche simulation and Allele frequency and environmental factor correlation analysis showed that temperature affected the distribution of X.sorbifolium,and the suitable growth range of X.sorbifolium gradually moved to the northeast from the last glacial maximum to now.The MaxEnt model shows that this species grew from the southern region of the Yangtze River and gradually adapted to cold conditions,growing on a large scale in the northwest region of China,forming the suitable growth range for the current distribution of X.sorbifolium,which gradually moved towards the northeast from the last glacial period to the present.[Conclusion]Based on the results of the study,we conclude that there is a rich diversity in the wild resources of X.sorbifolium,and the Yellow River and Meridian Ridge have influenced its genetic distribution during the evolution of X.sorbifolium,and its future distribution has a tendency to expand.