基于分子群体遗传学、谱系地理学及群体基因组的枇杷驯化遗传学的研究

In Han dynasty, before 2000 years ago, the loquat had been cultivated as “famous fruits and bizarre trees” in royal gardens. In about 12th century, the loquat was introduced to Japan, then to other fitting growth countries and areas. As the cultivated crop, however, the issues of domestication genetics such as where the cultivated population of loquat domesticated from? Was the cultivated population of loquat domesticated from monophyly, paraphyly or polyphyly？ whether the activity of domescation had induced the genetic bottleneck as other cultivated crops done？ How the selection effect during the domestication procession affected the genetics structure of culvated populations of loquat？ Etc, have not been studied. The applicant and the collaborators of this project had conducted extensive surveys on the wild loquat resources in China, and understand fully its geographical distribution, in the meanwhile, the cooperation unit had collected most commercial loquat cultivars in the world and planted them in the loquat germplasms nersery. On this basis, we intend to sample wild loquat populations from its species distribution range and whole commercial loquat cultivars collected, and conduct an integrated research to the sample using the methods and theories of phylogeography, molecular population genetics and population genomics. Our aim is to answer above scientific questions for the domestication of cultivated loquat. We believed the research results would help to add our knowledge about the origin and evolution of Eriobotray japonic, and guide our breeding tacit to improve cultivated loquat based on the wild resource.

早在2000多年前的汉代，枇杷即在皇家园林中作为名果异树栽培，到公元12世纪，枇杷被引到日本，然后从中国和日本传向世界其他宜栽国家和地区。然而，枇杷栽培类群究竟起源我国何地？为单系还是多系驯化？驯化是否造成了严重的遗传瓶颈？驯化过程中的选择作用是如何影响现代栽培枇杷的遗传结构等驯化遗传学问题尚未被研究。项目申请者和合作申报单位已对我国野生普通枇杷资源进行了广泛调查，充分了解了它的地理分布，同时，合作单位的枇杷资源圃收集了世界上绝大部分商业枇杷品种。在此基础上，我们拟对物种分布范围的野生枇杷居群和收集到的全部栽培枇杷品种进行采样，综合运用谱系地理学、分子群体遗传学、群体基因组学的理论及方法对样本进行研究，旨在对枇杷驯化这个科学问题进行解答。相信研究结果将不仅有助于人们更好地认识枇杷的起源演化，对指导人们利用枇杷野生资源来改良现有的栽培枇杷和培育新的有价值的枇杷品种也具有重要的指导意义。

项目背景：枇杷是一种重要的热带和亚热带水果，味道鲜美，营养丰富全面。栽培枇杷最早起源驯化于我国汉代，然而，栽培枇杷究竟是起源驯化于我国何地，是单系驯化起源还是多系驯化起源，栽培枇杷在驯化后与野生枇杷是否存在基因交流等？基于此，本项目综合利用分子遗传学、谱系地理学和群体基因组学，试图解答以上问题。.重要结果：我们采集了将近60个来自贵州、四川、重庆、湖南和湖北的野生枇杷群体。并对对其中的30个群体进行了群体遗传学和谱系地理学研究。我们结合53个栽培枇杷品种和采集的60份野生枇杷进行了基因组测序，同时我们还对大五星枇杷进行了全基因组进行了测序。我们组装一个高质量的枇杷基因组草图，群体基因组分析显示栽培枇杷群体起源于单一驯化事件，最早驯化地是在湖北宜昌周围山区，现在的栽培枇杷群体与野生群体不存在明显的基因交流。.关键数据：大五星枇杷：36G的3代测序数据，52G2代测序数据。其它的112份枇杷，各5-10G的2代数据。.科学意义：系统阐明了枇杷驯化的遗传学问题，不仅可以人们对我国古代多样性农耕文明的认识，对枇杷的的遗传学、分子生物学、园艺学等生命科学研究提供了全面的基因组数据参考。