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跳枝碧桃花色性状的全基因组关联分析

花匠小妙招
2025-01-11 19:47

摘要：

跳枝碧桃（Prunus persicaf. versicolor）在同一植株上可产生二色花和嵌合花,具有很高的观赏价值。以南京3个观赏桃集中分布区的57株跳枝碧桃为材料,利用简单重复序列（SSR）标记研究其遗传背景。通过PCR扩增,筛选出6对多态性引物,共计扩增出17个多态性条带,平均有效等位基因2.83个。SSR标记基因分型结果表明,供试材料可分为3种基因型,各采样地均具有2 ~ 3种基因型,同一植株的不同分枝基因型完全一致。基于基因分型结果,选取3种基因型跳枝碧桃各1株进行基因组重测序,结合公开发表的数据,进行位点变异分析,并构建系统发育树。结果显示3种基因型的跳枝碧桃聚在一个分支,其中B20、T3基因型与‘洒红桃’聚在一起,W5基因型相对独立。3种基因型的跳枝碧桃在起源上比较接近,但不同基因型之间存在一定的遗传差异。通过整合单核苷酸多态性（SNP）信息和花色表型开展全基因组关联分析（GWAS）,鉴定出5个SNP与花色跳枝性状显著关联（P值 < 10 -100）,均位于7号染色体。在显著SNP位点的邻近基因组区段发掘3个DICER-LIKE 2（DCL2）基因,揭示在桃树花色跳枝性状的形成中,依赖DCL2的表观遗传修饰途径可能发挥重要作用。

关键词: 跳枝碧桃, SSR标记, 基因组重测序, 系统发育树, 全基因组关联分析

Abstract:

Purnus persica f.versicolor has high ornamental value with its two-color and variegated flowers in one single plant. Here,57 P. persica f. versicolor trees from three main distribution areas of ornamental peach were genotyped using Simple Sequence Repeat（SSR）markers. Seventeen polymorphic bands were amplified using six polymorphic primer pairs;the average of effective allele numbers was 2.83. Based on genotyping results by SSR markers,the samples were grouped into three genotypes,of which two to three genotypes were obtained from each collection area. The genotypes of different branches from one peach tree were identical. Further,one representative tree of each genotype was used for the genomic resequencing and variant calling. And phylogenetic analysis was then performed in combination with public genomic resequencing dataset. The results showed that individuals of the three peach genotypes were clustered into one clade,although B20 and T3 were closely related to‘Sahongtao’,whereas W5 was relatively independent,indicating the three genotypes ofP. persica f.versicolorwere cultivated from closely related clones with limited genetic variations. Genome-wide association study（GWAS）was further carried out by integrating single nucleotide polymorphism（SNP）information and flower color phenotypes. Five SNPs significantly associated with flower color trait（P < 10 -100）were identified and all of them were located on chromosome 7 of peach genome. Three Dicer-like 2（DCL2）genes were identified in genome segments adjacent to correlated SNP loci,suggesting that DCL2-dependent epigenetic modification may play an important role in the formation of variegated flowers in peach.

Key words: Purnus persica f.versicolor, SSR marker, genomic resequencing, phylogenetic tree, GWAS

中图分类号:

S662.1