冬瓜果皮颜色基因的精细定位

Fruits have vital importance in the human diet, and fruit skin colour is one of the most important traits for both commercial and esthetic value of fruit. Consequently, it has been one of the research priorities of breeders for a long time. Previously, we have completed the genome sequencing and transcriptome sequencing of wax gourd, and a lot of SSR markers were obtained. Besides, the inheritance of fruit skin colour of wax gourd was also studied, which showed that a single dominant nuclear gene determines the black fruit skin colour. Based on our previous studies, in order to build a high-density linkage map of wax gourd by SSR markers, we use the F2 population as materials, which was constructed by the inbreds with black and yellow fruit skin. Subsequently, based on the phenotypic data of each F2 segregating population, the fruit skin colour gene is preliminarily mapped on the genetic linkage map of wax gourd. Furthermore, using greater F2 population as materials, the flanking markers linked to fruit skin colour gene are used to screen recombinant plants. Eventually, fine mapping of fruit skin colour gene is achieved. The results of this study will not only laly a solid foundation for marker-assisted selection and gene cloning, but also provide a reference for the gene mapping of other agronomic traits, which has important theoretical and practical significance.

果实在人类饮食中占有十分重要的地位，而果皮颜色是影响果实商品价值和审美价值的最为重要的性状之一，因此长期以来一直是育种家的研究重点。项目组前期完成了冬瓜全基因组测序和转录组测序，获得了大量SSR标记。此外，研究了冬瓜果皮颜色的遗传规律，结果表明黑色果皮与黄色果皮为一对核基因控制的质量性状，黑色对黄色为显性。本项目在前期的研究基础上，以黑色果皮与黄色果皮自交系构建的F2群体为材料，利用SSR标记构建冬瓜高密度遗传连锁图谱。随后利用F2分离群体各单株果皮颜色的表型数据，在冬瓜遗传连锁图谱上初步定位果皮颜色基因。进一步以更大的次级分离群体为材料，利用初步定位获得的与果皮颜色基因两侧连锁的标记进行重组株筛选，最终实现该的精细定位。本研究结果不仅为冬瓜分子标记辅助选择育种、基因克隆等研究奠定基础，而且为其他农艺性状基因定位提供参考，具有重要的理论和实践意义。

果皮颜色是影响果实商品价值和审美价值的最为重要的性状之一，长期以来一直是育种家的研究热点。果皮颜色是冬瓜果实成熟期性状，获得与之紧密连锁的分子标记或可直接利用的基因，可在苗期进行分子标记辅助选择育种，提高选择的准确性，从而提高育种效率。本项目以果皮黑色与果皮黄色自交系构建的F2群体为材料，构建了冬瓜高密度遗传图谱，包含12个连锁群、4607个标记，将果皮颜色基因定位于第5连锁群，与两侧标记间的遗传距离分别为1.0 cM和1.9 cM。进一步根据冬瓜作图亲本及核心资源的全基因组信息，重点比较皮色基因定位区间内的候选基因序列，筛选到1个候选基因MYB类转录因子。共发表学术论文4篇，其中SCI论文1篇。相关成果荣获广东省科学技术奖二等奖及中国热带作物学会科技进步奖一等奖各1项。项目主持人荣获中国热带作物学会青年科技奖，并入选‘广东特支计划’科技青年拔尖人才、广州市珠江科技新星、广东省农业科学院金颖之星及青年研究员等人才计划。本项目不仅定位了果皮颜色基因，而且筛选到1个候选基因，为后续开展果皮颜色基因的功能研究奠定了重要的理论基础。