In addition to Yunnan Province, Hainan Province also possesses abundant tea plant resources, particularly in tropical rainforest areas such as Wuzhi Mountain. These tea plant resources urgently require in-depth research and utilization. However, due to the lack of modern genomic data support and comprehensive surveys of tea plant resources, the taxonomic status and population genetic diversity of Hainan large-leaf tea have not been fully resolved. Whole-genome resequencing analysis can not only infer biological population diversity and genetic structural variation but also provide new perspectives for studying evolutionary relationships among populations and their demographic history. Over the past three years, our laboratory has collaborated with institutions such as the Hainan Academy of Agricultural Sciences and the Wuzhi Mountain Nature Reserve, using whole-genome resequencing technology to conduct population analysis of Hainan large-leaf tea from four major tea-producing regions in Hainan Province, detecting its genetic variation information. Combined with resequencing data of multiple cultivated tea plants and other Camellia species from public databases, we completed genetic structure and phylogenetic analyses. Furthermore, the research team conducted in-depth investigations into the genetic evolutionary relationships and genetic diversity between Hainan large-leaf tea and cultivated tea. The results showed that Hainan large-leaf tea possesses rich genetic diversity and represents a new species distinct from cultivated tea. These findings provide reliable data support for multiple research directions on Hainan large-leaf tea, including tea plant taxonomy, genetic background, and genetic diversity, while also providing an important scientific basis for its germplasm conservation and molecular breeding.
The study used SNPs and chloroplast data to construct phylogenetic trees, in which Hainan large-leaf tea consistently formed an independent branch without mixing with any other Camellia species. Secondly, in population genetic structure analysis, Hainan tea exhibited a genetic background completely distinct from other Camellia species. Among them, Hainan large-leaf tea from the Limu Mountain region showed a genetic background different from other Hainan large-leaf tea, representing a special subspecies of Hainan large-leaf tea. Compared with other Camellia species, Hainan large-leaf tea possesses an independent genetic background, providing evidence for its recognition as a new species within the genus Camellia.
Kinship analysis results showed that most individuals of Hainan large-leaf tea did not exhibit significant kinship relationships, and no sample pairs resulting from asexual reproduction were detected, indicating that the Hainan large-leaf tea population primarily expanded through outcrossing sexual reproduction rather than asexual methods such as cutting propagation. Nucleotide diversity results showed that Hainan large-leaf tea has higher genetic diversity than cultivated tea, a conclusion further supported by the greater number of nonsynonymous SNP mutations. Additionally, gene flow results further indicated that gene exchange between Hainan large-leaf tea and cultivated tea has been blocked due to geographic isolation. In the chloroplast-based phylogenetic tree, some Hainan large-leaf tea individuals showed closer genetic relationships with cultivated tea, providing evidence for maternal inheritance between Hainan large-leaf tea and cultivated tea. Further results showed that Hainan large-leaf tea, distant from the outgroup, first clustered with CSS (Camellia sinensis var. sinensis) and then with CSA (Camellia sinensis var. assamica), suggesting that Hainan large-leaf tea may have first experienced gene exchange with CSA and subsequently with CSS. However, the frequency of these gene exchanges was low, and with the increasing impact of geographic isolation, no obvious traces of gene exchange could be detected in the nuclear genome information of Hainan large-leaf tea.
This study established a germplasm resource database and product traceability system for Hainan large-leaf tea. It documented germplasm resources, genomic, population genetic, and industrial big data, laying a foundation for better protection and utilization of large-leaf tea germplasm resources and promoting high-quality development of the large-leaf tea industry. Through the establishment of a product traceability information platform, product quality and safety traceability was achieved, promoting transparency and scientific approaches in production, sales, and regulation, which is conducive to enhancing product market competitiveness and brand recognition.
To facilitate data resource sharing and biological resource digitization of Hainan large-leaf tea, the research team compiled germplasm resource, industrial data, and related information into a database. The Hainan Large-Leaf Tea Database was constructed, including basic information on genetic resources, distribution information of genetic resources, downloadable genomic sequencing data, industrial information data, relevant expert profiles, and public news information. The development of this database provides strong support for the digitization of Hainan large-leaf tea biological resources and industrial development.
To ensure the orderly development of the Hainan large-leaf tea industry and prevent counterfeit and substandard products from disrupting the market, the research team developed an online Hainan large-leaf tea product traceability system. Currently, the traceability system includes 40 statistical data items, covering product information, origin, price, raw material processing, taste evaluation, and other aspects, ensuring comprehensive product monitoring. Real-time data upload and synchronization are maintained, and information can currently be queried at http://hntea.org.cn/tracetea. In addition, the research team has currently collected traceability information for nearly 70 tea product categories from more than 20 manufacturers, and will continue to upload and update data in real time. Through the establishment of a product traceability information platform, product quality and safety traceability is achieved, promoting transparency and scientific approaches in production, sales, and regulation, which is conducive to enhancing product market competitiveness and brand recognition.