基于桃种间导入系重要经济性状基因的挖掘

Peach [Prunus persica (L.) Batsch] is one of the most important economic crops in China, accounting for more than 50% cultivated area of the world. As a perennial woody plant, artificial selection caused a low level of genetic variability within peach cultivars. In current peach breeding approach, new elite commercial genes from interspecific hybrid and wild relatives needed to be identified and introgressed into the peach. Additionly, due to the lack of single chromosome fragment introgression line (near isogenic lines) materials, the QTLs are usually not validated in different genetic backgrounds, making it difficult to extrapolate their magnitude and robustness to different breeding programs. The genetic mechanism of many economically important traits is still unclear. In this proposal, BC1 plants from interspecific hybrid were genotyped with deep resequencing and selected the core preNIL individuals covering the entire genome of P.davidiana (Pp1-8) and some of economically valuable traits (quality traits and major QTLs) were mapped. In this proposal, the BC2 lines are further constructed. Marker-assisted selection is used to identify the offspring individuals of BC2 and BC1 self pollination population with a single introgression of P.davidiana. For their genetic analysis, the lines are divided into the two phenotypic classes and we will compare their graphical genotypes to discover desired traits, including fine mapping, candidate gene cloning and validation. This project will lay the foundation for novel germplasm enrichment, genetic improvement and genetic mechanism illustration of important traits in peach.

桃[Prunus persica（L.）Batsch]是我国最重要的经济作物之一，栽培面积占世界总量的50%以上。作为多年生木本植物，人工选择致使桃品种间遗传背景狭窄，亟需利用和挖掘种间优异资源基因开辟新的遗传改良途径。同时，由于缺乏单片段导入系（近等基因系）材料，致使QTL定位精度低，重复性差，许多重要经济性状的遗传机制仍不清楚。本项目前期构建了BC1群体，基于重测序筛选出了覆盖山桃全基因组（Pp1-8）导入片段系的PreNIL核心单株，并初步定位了桃重要经济性状基因（质量性状和主效QTLs）。在此研究基础上，拟继续开展种间片段导入系的构建工作。利用分子标记辅助鉴定BC2回交系和BC1自交系中仅含供体单一短片段的单株，结合基因分型和表型挖掘桃重要经济性状基因，完成相关基因的精细定位、候选基因克隆和验证。本项目的顺利实施可为新种质创制、品种遗传改良和重要性状的遗传机制解析奠定基础。

桃[Prunus persica（L.）Batsch]是我国最重要的经济作物之一，栽培面积占世界总量的50%以上。作为多年生木本植物，人工杂交致使桃品种间遗传背景狭窄，亟需利用和挖掘种间优异资源基因，开辟新的遗传改良途径。同时，由于缺乏单片段导入系（近等基因系）材料，致使QTL定位精度低、重复性差，许多重要经济性状的遗传机制仍不清楚。本项目构建了BC1群体，筛选了覆盖山桃全基因组（Chr 1-8）导入片段系的PreNIL核心单株，精细定位了桃外果皮绒毛、花和果皮颜色、果肉颜色、单果重和垂枝性状等重要经济性状基因（质量性状和主效QTLs）5个。基于种间导入系精细定位和确定了控制桃外果皮毛/油性状的候选基因，开发了分子标记；确定了控制桃花/果皮颜色的基因PpGST并验证了该基因的功能，基于5-bp缺失和2bp插入开发了分子标记并应用于分子标记辅助选种，创制了桃“纯色”，特别纯黄类型新种质。结合基因型和表型挖掘了桃重要经济性状基因，完成了相关基因的精细定位、候选基因克隆和验证。本项目的顺利实施为新种质创制、品种遗传改良和重要性状的遗传机制解析奠定了基础。