桃地方品种果实糖酸主要组分的遗传关联分析

Genetic association of sugar and acid main constituents of China landrace peach(Prunus persica L.)

【目的】定位桃果实糖酸主要组分的QTLs(Quantitative Trait Loci),获得与其相关的分子标记,应用于分子标记辅助育种。【方法】以来源于中国6个生态群96份桃地方品种为试材,采用定位于桃8条连锁群上的52对SSR(Simple Sequence Repeats)标记引物,用STRUCTURE 2.3.3和TASSEL2.0.1软件分别对群体结构和全基因组SSR位点间的连锁不平衡(Linkage Disequilibrium,LD)状况进行分析。再结合糖酸组分中的果糖、葡萄糖、蔗糖、山梨醇,可滴定酸和果肉p H等表型数据后进行关联分析。【结果】群体结构显示供试的96份桃地方品种基于ΔK数学模型可以分为7个亚群;LD分析表明在52个SSR位点组成的1 326个成对组合中,198个成对位点存在着显著LD且得到统计概率支持。相关性分析表明,山梨醇与蔗糖、葡萄糖呈极显著正相关,与p H呈显著正相关;蔗糖与葡萄糖、p H呈极显著正相关,与果糖呈显著正相关;葡萄糖与p H、果糖呈极显著正相关;p H与可滴定酸呈显著负相关。本研究共得到39个与桃糖酸组分相关的主效QTL,依次为:5个果糖相关的QTL,11个葡萄糖相关的QTLs,5个蔗糖相关的QTLs,9个山梨醇相关的QTLs,5个可滴定酸相关的QTLs,及4个p H相关的QTLs。部分位点与前人定位的连锁群相同,部分QTLs位点同时调控多个糖、酸组分。【结论】本研究共得到57个桃糖酸组分的QTLs,有53个QTLs为首次报道,表型变异率大于10%的有39个,经Bonferroni多重检验校正后,标记效应大于10%存有4个,分别是与p H关联的位点BPPCT023.2011、UDP96-013.2011、与山梨醇关联的位点CPPCT030.2011、与果糖关联的位点CPPCT033.2012,具潜在的育种标记开发利用价值。

[Objective]This study aims to map the QTL of sugar and acid main constituents of peach fruit and find the markers associated to the trait through association analysis which can be applied for markerassisted breeding. [Methods ] 96 peach landrace accessions from 6 Chinese geographical regions were evaluated about sugar and acid main constituents traits. 52 SSR （Simple Sequence Repeats） primers were evenly selected from peaches TxE reference map （519 cM） to ensure broad genome-wide coverage. STRUCTURE 2.3.3 software was applied to estimate sample population structure, using TASSEL2.0.1 software to measure LD value between SSR loci, GLM （General Linear Model）^[10] model, combining characters traits data of fructose, glucose, sucrose, sorbitol, titratable acidity and pulp pH were used to make regression analysis. [Results] Correlation analysis showed that sorbitol were significantly positively correlated with sucrose, glucose and positively correlated with pH. Sucrose were significantly positively correlated with glucose, pH and positively correlated with fructose. Glucose were significantly positively correlated with pH, fructose, pH showed highly significant negative correlation to titratable acidity. Population structure analysis showed that the tested 96 peach cultivars can be divided into 7 subgroups based on mathematical models ; LD analysis showed that 1 326 pairwise combinations were consist of 52 SSR loci, in which 198 pairwise sites had significant LD and supported by statistical probability at P ≤ 0.05 level. Phenotypic variation of 39 SSR loci were higher than 10%, they were 5 Fructose QTLs, 11 glucose QTLs, 5 sucrose QTLs, 9 sorbitol QTLs, 5 Titratable acid QTLs, 4 pH QTLs, respectively. And many of them were located in same chromosomes which were obtained using linkage analysis previously. Some QTLs controlled both sugar and acid trait. After the Bonferroni multiple test, only 4 had statistical significance. [Conclusion]A total of 57 sugar and acid constituents QTLs were found. There are 53 QTLs reported for the first time, phenotypic variation of 39 SSR loci were higher than 10%. After the Bonferroni multiple test, there are still remain sites BPPCT023.2011 and UDP96-013.2011 associated with pH, site CPPCT030.2011 associated with sorbitoland, site CPPCT033.2012 associated with fructose; the main effect QTLs mapped in this study will be useful to the further marker-assisted breeding development.