| Ziziphus jujuba Mill.belongs to the genus Ziziphus of the Rhamnaceae family and has a long history of cultivation and domestication.In the long-term cultivation,there are abundant variations in fruit size among different genotypes,but the molecular regulation mechanism leading to these variations is not clear.In this study,two germplasm groups with contrasting fruit size were used for reduced-representation genome sequencing.SNP markers were obtained to analyze the genetic relationship,population genetic structure and genetic diversity.Selection regions in the genome were identified by multiple strategies.Further bioinformatics analysis of the gene functions and pathways of the gene within the selected region.And genes detected by multiple analysis and candidate genes associated with the cell cycle regulation,cell division and hormone were compared and analyzed in ’Tongbaidazao’ and sour jujube in different fruit development stages.The main results were as follows:(1)Large fruit and small fruit group:a total of 130077 high quality SNPs were obtained.The genetic diversity of large fruit type jujube germplasm(π:0.3214)was lower than that of small fruit type jujube germplasm(π:0.3273).The large fruit type jujube germplasm had a high linkage disequilibrium,and had a heterozygous selection advantage.83 and 149 selected genes were detected in the large fruit and small fruit groups,respectively.(2)Cultivated fruit and wild jujube group:a total of 315915 high quality SNPs were obtained.The genetic diversity of cultivated fruit and wild jujube were:π:0.3100 and 0.3236,respectively.The genetic diversity of wild jujube was higher,and different cultivated jujube varieties may be independently domesticated from different sour jujubes.At last,124 selected genes were identified by four methods.(3)Two groups analysis identified 8 important candidate genes involved in cell cycle,cell division or hormone synthesis regulatory pathways(LOC107404981,LOC107406728,LOC107424132,LOC107426306,LOC107418232,LOC107432595,LOC107418355 and LOC107411529).qRT-PCR analysis showed that the candidate genes LOC107404981,LOC107406728 and LOC107418355 increased more expression in 45 and 75 days after flowering,they may play important role in the regulaton of jujube fruit size.(4)The candidate gene ZjTIFY10 was successfully cloned from ’Dongzao’ and an over-expression vector PRI101-AN-ZjTIFY10 was constructed and transformed with sour jujube using Agrobacterium-mediated method. |
