枸杞果糖含量性状主效QTL定位及候选基因分析

Wolfberry ( Lycium L. ) is an important drug and food plant resources, and the fruit possessed various of health functions. The traditional Chinese doctors and gourmets always attached high attention to wolfberry fruits. But the genetic background of wolfberry is highly heterozygous, lacking of genomic information, and the traditional methods of genetic improvement were of long period and inefficient, which greatly limited the process of genetic improvement in wolfberry fruit quality. To speed up gene excavation and study on the important good traits of wolfberry fruit, and SNP molecular marker-assisted selection was widely used in the genetic improvement of wolfberry. In this study, F1 separate groups were derived from the cross‘Ningqi NO.1’and‘Yunnan’, and high-density SNP genetic linkage maps were constructed by specific length amplified fragment sequencing (RAD-seq) and pseudo-testcross theory; Genetic research and mapping of major QTL regions on fructose content in Wolfberry by genetic linkage maps and more than two years phenotypic test datum; Utilization of wolfberry genomic sequence annotation section main effect gene function, and screening candidate genes associated with fructose metabolism, expression analysis of candidate genes in parents. This study will provide the theory of basis and means for the future of Lycium genome mining and quality improvement.

枸杞（Lycium L.）是我国重要的药食两用植物资源，其果实具有多种保健功能，历来备受中外医食家高度关注。但由于枸杞遗传背景高度杂合、基因组信息缺乏，传统遗传改良方法耗时长效率低，极大限制了枸杞品种改良进程。为加快枸杞果实糖含量性状基因挖掘，开展SNP分子标记辅助选择在枸杞品质改良中应用。本研究以大果高果糖型‘宁杞1号’×大果低果糖型‘云南枸杞’构建 F1分离群体，采用简化基因组测序技术和“拟测交”作图策略，构建首张枸杞高密度SNP遗传图谱；利用气相色谱（GC）法测定亲本及子代果实果糖含量，收集两年以上的果糖含量数据，对果糖含量性状QTL区段进行定位，筛选果糖含量性状的主效QTL区段；利用枸杞基因组序列注释主效区段基因功能，并筛选与果糖代谢相关候选基因，分析候选基因在亲本中表达差异。本研究将为今后枸杞功能基因挖掘和品质改良提供理论依据和选择手段。

枸杞是我国重要的药食两用植物资源，其果实具有多种保健功能，历来备受中外医食家高度关注。但由于枸杞遗传背景高度杂合、基因组信息缺乏，传统遗传改良方法耗时长效率低，极大限制了枸杞品种改良进程。为加快枸杞重要性状基因挖掘，开展分子标记辅助选择在枸杞品质改良中应用。本课题以‘宁杞1号’为母本，‘中国枸杞’与‘云南枸杞’为父本，构建2个种间杂交群体，杂交群体后代数量超过500株，采集连续3年表型数据，且群体表型性状呈现出连续（近）正态分布，符合数量性状变异特征；采用简化基因测序与全基因组测序技术，分别开发出6733 与8507 个可用于构建遗传图谱、高质量SNP标记，并利用HighMap软件构建2张枸杞高密度遗传连锁图谱，总图距分别为1,702.45 和2,122. 24 cM，平均图距分别为0.253和0.25 cM；进一步利用高密度遗传连锁图谱和遗传群体后代表型性状数据，获得枸杞果叶性状相关稳定QTL 55个，其PVE与LOD值变异范围分别为4.3~30.9% 与2.5~17.24；获得枸杞果实糖分含量相关QTL 22个，其PVE与LOD峰值分别为7.1%~11.9%与2.51~4.12；通过对枸杞果实糖分含量相关4个主效QTL上SNP与参考基因组比对，并在公共数据库GO，KEGG上注释，获得19候选基因可能参与枸杞糖分积累。本研究有助于加快枸杞果实相关性状重要功能基因解析和标记开发，进而指导枸杞新品种遗传改良。