| During the long process of evolution and domestication,tea plant has gradually adapted to climates in different places,forming typical local adaptation characteristics,but its adaptation mechanism is still unclear.Understanding the genetic basis of the tea tree’s climate adaptation could help mitigate the risks posed by global climate change.In order to study the genetic basis of climate adaptability in tea plant,Genotyping by Sequencing(GBS)was performed on 254 tea plant.Combined with selective sweep analysis and genome-wide association analysis of the environment,we explored the gene imprinting of tea plant in adapting to different regional climates from the genome level,and screened out the key climate factors and genes that may play an important role in the climate adaptability differentiation of tea plant.The main results are as follows:1.GBS sequencing was performed on 254 tea plant from 11 provinces,and 187,115 high-quality SNP loci were screened.Based on these SNPs,population structure analysis,phylogenetic tree analysis,principal component analysis and Linkage disequilibrium analysis were performed on 254 tea plant.The results showed that the 254 tea plant could be divided into 5 populations,and the genetic distribution and geographical distribution of tea plant were consistent.In addition,the Linkage disequilibrium analysis showed that LD attenuation patterns were two in the five populations,and the coastal(pop1,pop2,ppo3)and inland tea plant populations(pop4,pop5)showed large differentiation.The genetic diversity of inland populations was higher than that of coastal populations.2.The whole-genome selection imprinting of coastal and inland tea populations was investigated by three selective sweep analyses.Through GO and KEGG analysis of selected genes,which showed that most of the selected genes between coastal and inland populations were involved in protein binding,morphogenesis and photosynthesis,and the genes with functional annotation mainly focused on plant hormone signal transduction pathways and functional pathways of tissue development.3.The 19 bioclimatic factors were obtained in the Worldclim web.According to the analysis of gradient forest and correlation,six climate factors that had a great influence on the genetic differentiation of coastal and inland tea plant populations were selected,which were respectively average annual temperature,maximum temperature in the hottest month,annual temperature difference,precipitation in the wettest month,seasonal variation of precipitation,and precipitation in the coldest quarter.Based on the screened high-quality SNP sites with six key climate factors.A total of 154 core climate adaptation loci were identified by the two environmental and genome association analyses(latent factor mixed model ‘LFMM’ and redundancy analysis ‘RDA’),and the genes at these loci were mainly related to phosphorylation pathway and respiration pathway.In order to evaluate the identified climate core loci,we used Mantel test to analyze the geographical isolation model and environmental isolation model of core climate loci.The results showed that the genetic variation of adaptive variation in coastal and inland tea tree populations was mainly influenced by the environment.By overlapping any two selective clearing methods with the core sites of climate adaptation,a total of 6 genes were screened,which were PAP gene related to average annual temperature,TLPs and FBK genes related to annual temperature difference,IDE gene related to seasonal precipitation change,TMV N-like X1 gene related to precipitation in the coldest quarter.The ATG11 gene was associated with precipitation in both the wettest month and the coldest quarter.These genes are related to stress resistance and physiological function of plants,and may be the key regulatory factors of tea tree adaptation to different environmental stresses. |
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