杏果实中调控有机酸积累的QTL定位及其主效基因筛选

doi:10.16420/j.issn.0513-353x.2024-0438

摘要/Abstract

摘要：

以‘串枝红’为母本和‘骆驼黄’为父本构建杏F₁杂交群体，并采用液相色谱测定果实中苹果酸、柠檬酸和总酸含量，同时，利用重测序数据挖掘杂交群体的SNP变异信息，构建杏遗传连锁图谱。结果表明，苹果酸在发育过程中先升高后降低，而柠檬酸呈出一直升高的变化规律。苹果酸和总酸具有典型的数量遗传特征，而柠檬酸呈现偏正态分布，可能存在主效调控基因。杏遗传连锁图谱标记平均距离为0.52 cM，利用该图谱定位获得11个QTL，其中，与苹果酸相关区间包含88个基因，与柠檬酸相关包含310个基因，与总酸相关包含40个基因。加权基因共表达网络分析（WGCNA）表明苹果酸、柠檬酸和总酸分别与模块m13、m05和m08显著相关，富集分析发现柠檬酸相关候选基因主要与三羧酸循环循环（TCA）、丙酮酸代谢、糖酵解/糖原异生等途径和通路相关。对QTL、WGCNA和TCA循环涉及的基因取交集，发现仅PA08G28879在三者中同时出现，其可能是调控杏果实中柠檬酸积累的主效基因（PaMDH1），可作为探索杏果实有机酸积累分子机制的候选基因。

关键词: 杏, 杂交群体, 有机酸, 遗传变异, QTL定位

Abstract:

Based on a cross between Chuanzhihong（female）and Luotuohuang（male），an F₁ hybrid population of apricot was constructed. The levels of malic acid，citric acid，and total acids in the fruits were determined using liquid chromatography. Additionally，SNP variations in the hybrid population were identified through resequencing data to construct a genetic linkage map for apricots. The findings revealed that malic acid levels increased initially and then decreased during fruit development，while citric acid levels showed a continuous increase. Malic acid and total acids displayed typical quantitative genetic characteristics，whereas citric acid exhibited a positively skewed distribution，indicating the presence of major regulatory genes. The average inter-marker distance in the apricot genetic linkage map was 0.52 cM. Using this map，a total of 11 QTLs were identified，with 88 genes associated with malic acid，310 genes associated with citric acid，and 40 genes associated with total acids. WGCNA analysis demonstrated significant correlations between malic acid，citric acid，total acids，and modules m13，m05，and m08，respectively. Enrichment analysis revealed that candidate genes associated with citric acid were primarily involved in the TCA cycle，pyruvate metabolism，glycolysis/gluconeogenesis，and other related pathways. Intersection analysis of genes related to QTLs，WGCNA，and the TCA cycle identified a single gene，PA08G28879（PaMDH1），present in all three analyses，which may serve as the major gene regulating citric acid accumulation and the candidate gene for exploring the molecular mechanism of organic acid in apricot fruits.

Key words: apricot, F₁ population, organic acids, genetic variation, QTL mapping

姜凤超, 杨丽, 张俊环, 张美玲, 于文剑, 孙浩元. 杏果实中调控有机酸积累的QTL定位及其主效基因筛选[J]. 园艺学报, 2025, 52(4): 846-856.

JIANG Fengchao, YANG Li, ZHANG Junhuan, ZHANG Meiling, YU Wenjian, SUN Haoyuan. QTL Mapping and Identification of Major Genes Regulating Organic Acid Accumulation in Apricot Fruits[J]. Acta Horticulturae Sinica, 2025, 52(4): 846-856.

图/表 6

图1 杏果实不同发育时期有机酸及其组分的含量变化

Fig. 1 Content variations of malate，citrate，total acids in apricot fruits at different stages of development

图2 2015年与2016年杏杂交群体苹果酸、柠檬酸和总酸含量的频次分布

Fig. 2 Frequency distribution of malate，citrate，and total acid content in apricot hybrids for the years 2015 and 2016

图3 杏遗传图谱标记密度分布与QTL定位结果（2015和2016年）

Fig. 3 Apricot genetic map marker density distribution and QTL mapping results（2015 and 2016）

表1 苹果酸、柠檬酸和总酸的QTL定位结果

Table 1 QTL mapping results for malate，citrate，and total acids of apricot

性状 Traits	年份 Year	染色体 Chromosome	QTL/cM	物理位置 Physical location	LOD	基因数量 Gene numbers
苹果酸 Malate（88）	2015	Chr3 Chr6 Chr8	10.7 ~ 11.1 74.9 ~ 75.3 25.9 ~ 26.6	4.4 ~ 4.6 27.6 ~ 27.7 11.0 ~ 11.3	3.1 ~ 3.2 2.9 ~ 3.8 5.9 ~ 6.8	22 16 47
苹果酸 Malate（88）	2016	Chr5 Chr8	43.1 ~ 43.4 25.9 ~ 26.6	10.7 ~ 10.7 11.0 ~ 11.3	2.9 ~ 3.0 5.3 ~ 6.5	3 47
柠檬酸 Citrate（310）	2015	Chr5 Chr8	48.5 ~ 51.2 30.9 ~ 34.0	12.0 ~ 12.7 13.1 ~ 14.4	3.3 ~ 3.5 4.6 ~ 6.6	66 209
柠檬酸 Citrate（310）	2016	Chr8 Chr8	22.9 ~ 23.6 51.1 ~ 51.3	9.7 ~ 10.0 21.7 ~ 21.8	5.0 ~ 5.1 3.1 ~ 3.2	32 3
总酸 Total acids（40）	2015	Chr5	4.7 ~ 5.3	1.2 ~ 1.3	3.6 ~ 3.7	9
总酸 Total acids（40）	2016	Chr8	50.9 ~ 51.6	21.6 ~ 21.9	3.6 ~ 4.6	31

图4 苹果酸、柠檬酸和总酸的WGCNA分析与富集分析 A：不同发育时期有机酸含量与基因表达量的相关性分析（G1：软核期；G2：硬核期；CT：转色期；FR：成熟期。C：串枝红；D：大白杏。1、2、3为3次重复）；B：WGCNA分析有机酸与模块的相关性分析；C：苹果酸和柠檬酸相关基因的富集分析

Fig. 4 Analysis of WGCNA and enrichment of malate，citrate，and total acids A：Organic acid content and gene expression levels at different developmental stages（G1：Soft-kernel stage；G2：Hard-kernel stage；CT：Coloring stage；FR：Fruit ripe. C：‘Chuanzhihong’；D：‘Dabaixing’. 1，2，3 represent three replicates）；B：WGCNA analysis of the correlation between organic acids and modules；C：Enrichment analysis of genes related to malic acid and citric acid

图5 杏基因组中三羧酸循环相关酶基因的鉴定及关键基因挖掘 A：TCA循环相关基因的表达分析（G1：软核期；G2：硬核期；CT：转色期；FR：成熟期。C：串枝红D：大白杏）；B：PaPMDH1基因与柠檬酸含量相关性分析（上方橙色表示柠檬酸含量的密度分布，右方绿色表示PaPMDH1 基因的表达量密度分布）

Fig. 5 Identification of tricarboxylic acid cycle-related enzyme genes in the apricot genome and exploration of key gene A：Expression analysis of TCA cycle-related gene（G1：Soft kernel stage；G2：Hard kernel stage；CT：Coloring stage；FR：Fruit ripe stage. C：‘Chuanzhihong’；D：‘Dabaixing’）；B：Correlation analysis between the PaPMDH1 gene and citric acid content（The orange area on the top represents the density distribution of citric acid content，while the green area on the right represents the density distribution of PaPMDH1 gene expression levels）

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