核基因组微卫星标记揭示大理茶参与了普洱茶的驯化过程

Genetic Involvement of Camellia taliensis in the Domestication of C.sinensis var. assamica(Assimica Tea) Revealed by Nuclear Microsatellite Markers

利用11个核基因组微卫星标记对普洱茶3个居群、大理茶3个居群及过渡型大理茶2个居群共104株古茶树进行了遗传学分析。研究表明,普洱茶、大理茶和过渡型大理茶居群的遗传多样性相对较低,平均等位基因(Na)为4.852,平均香农多样性指数(I)为1.17,平均期望杂合度(He)和观测杂合度(Ho)分别为0.59和0.52,其中大理茶的遗传多样性水平低于普洱茶和过渡型大理茶。AMOVA分析表明,普洱茶和大理茶之间遗传分化显著(FST=0.305),遗传变异主要在居群内(分别为93.51%和89.41%),而居群间的遗传变异较低(分别为6.49%和10.59%)。主成分分析和STRUCTURE聚类分析均支持大理茶和普洱茶为不同的组,过渡型大理茶主要由大理茶驯化而来,并在栽培过程中与大理茶产生了遗传分化。在混栽的大理茶和普洱茶居群间存在由大理茶向普洱茶的明显基因渐渗,证实了大理茶参与了普洱茶的驯化过程。最后,讨论并提出了对大理茶和普洱茶古茶树资源保护的相关建议。

The levels of genetic diversity and population structure were assessed for 104 ancient tea plants from three Camellia taliensis populations, three C. sinensis var. assamica populations and two transitional populations of C. taliensis based on data from 11 nuclear microsatellite loci. In this study, a relative low genetic diversity was revealed for all three population groups. The average number of alleles （Na） was 4. 85, the average Shannon＇ s diversity index （I） was 1.17, the average expected heterozygosity （He） and observed heterozygosity （Ho） was 0. 59 and 0. 52 respectively, for the studied populations. The level of genetic diversity of C. taliensis was lower than for C. sinensis var. assamica and the transitional C. taliensis. An AMOVA analysis indicated a significant genetic differentiation （ FST = 0. 305 ） between populations of C. sinensis var. assamica and C. taliensis. Most of the genetic variation was partitioned within population of C. sinensis vat. assamica （ 93.51% ） and C. taliensis （ 89.41% ）, and a low par-tition among populations （6.49% and 10. 59%, respectively）. Populations of C. sinensis var. assamica and C. taliensis （including the transitional populations of C. taliensis ） formed two distinct genetic clusters in a principal component analysis （PCoA） and in STRUCTURE clustering, which suggests that the transitional populations of C. taliensis originated mainly from C. taliensis, and then followed somewhat genetic differentiation during the process of domestication. Gene introgression was detected in the cultivated C. sinensis vat. assamica and C. taliensis from the same tea garden, and genetic material of C. taliensis apparently infiltrated into C. si^wnsis var. assamica. This study demonstrated that C. taliensis was genetically involved in the domestication of C. sinensis var. assamica. Finally, suggestions on how to protect the genetic resources of ancient tea plants are discussed on the findings in this study.