Research On The Origin And Evolution Of Ancient Tea Trees In Guizhou Based On Genome Resequencing

Camellia sinensis(L.)O.Kuntze belongs to the Camelliaceae family and was a relatively primitive population plant that originated in southwestern China.During the process of spreading from the place of origin to other regions,the A series of evolutions at the molecular level.In recent years,various new technologies and methods have been widely used to study the genetic evolution of tea plants,and have made some progress.At the genomic level,we combine the characteristics and characteristics of tea trees from the place of origin to discuss the origin of ancient tea trees in Guizhou Province and the genetic relationship of major wild resources.In this paper,90 ancient tea trees from Guizhou province and 30 ancient tea trees from Yunnan were used for whole-genome resequencing,and population genetics methods such as adjacent tree method,principal component analysis and genetic diversity were used to analyze them.We selected the main genera of the main distribution areas of ancient tea trees in Guizhou Province,and conducted the group evolution analysis of ancient tea trees for the first time,clarified the origin and kinship of ancient tea trees in Guizhou Province,provided strong support for the introduction of tea trees,and provided in-depth research on China Tea genetic diversity,genetic relationship and evolutionary path analysis provide a reference.The main results are as follows:1 Collection of 120 ancient tea tree samples and statistic data statisticsA total of 120 samples of ancient tea trees were collected from 6 populations in Guizhou Province and 2 populations in Yunnan Province.The 8 populations belonged to 5 groups under tea species.There was a certain degree of variation in the phenotypic data of ancient tea trees in Guizhou Province,and the average value of their genetic diversity index was 1.62.Morphologically,Guizhou ancient tea germplasm resources have many types of variation,complex genetic background,and rich germplasm resources,which provides a theoretical basis for the utilization of ancient tea germplasm resources in Guizhou.2 Statistics of whole genome resequencing resultsUsing Suchazao as the reference genome,a whole genome re-sequencing was performed on ancient tea tree samples in Guizhou Province using bioinformatics methods.A total of 8,082,370 SNP sites were detected,of which 6,675,596 were located in the coding region of the gene.One was a non-synonymous mutation,and85,058 were synonymous mutations;8082370 In Del sites were obtained,and there were 15816135 In Del sites in the coding region.It provides a lot of valuable basic data for further research and molecular breeding of tea plants.3 Origin and evolution of ancient tea trees in Guizhou ProvinceThe SNP loci of 120 samples were analyzed,and the population genetic structure showed that the CV error was the smallest when K = 7.The result was that only the samples of DY and YH had mixed ancestors,and the mixed ancestors were SQ;the results of the population evolution tree Based on the analysis of Dali tea as the original variety,the ancient tea tree in Guizhou Province was the oldest ancient tea tree,followed by the ancient tea trees in SD and XS,and then the ancient tea trees in DY,SQ and YH.Human studies have also proved that DY ancient tea tree Guiding Bird King has evolved from wild type to cultivated type,and most of them were close to cultivated type.4 Whole genome association analysisThe rapid decay of LD of ancient tea trees(10kb-20kb)supports that ancient tea trees were in a relatively weak choice during the growth process of the natural environment.For genome-wide association analysis,the CMLM model was used.The SNP site value in the Manhattan map exceeds the threshold value 8.The phenotypic data that forms the signal peak include leaf teeth,sawtooth depth,tree type,leaf quality,leaf tip,and ovary hair,less than 8.There was leaf length,leaf width,leaf area,leaf vein logarithm,leaf color,leaf shape,etc.This study further clarifies the evolutionary history of ancient tea trees in Guizhou Province,provides substantial and valuable genomic resources,and will greatly promote the improvement of tea tree germplasm and molecular breeding.Three plant type related GWAS signals were identified in TEA029928,TEA012294 and TEA028016 loci.RT-q PCR was used to verify the expression levels of GWAS mining representative genes in ancient tea tree populations with different traits.The results showed that the expression level of TEA021477 gene in light green leaves was significantly lower than that in dark green leaves.TEA029928 gene: The expression level of shrub type ancient tea was significantly higher than that of tree type ancient tea.