They confirmed that the island’s tea plants represent a distinct variant of Camellia sinensis, separate from the well-known Assam and Sinensis varieties. This research offers valuable insights into the genetic diversity, domestication, and conservation of Hainan tea, highlighting its unique evolutionary trajectory influenced by the island’s geography and climate.
Tea, cultivated in China for over 3,000 years, has long been an essential part of global culture. While extensive studies have focused on tea plants from southwestern China, little has been done on the tea of Hainan Island, known for its abundant wild tea trees. The genetic status of Hainan tea has remained unclear due to challenges in classification, primarily because of its similarities to C. sinensis var. assamica and its distinct geographical isolation. Previous research failed to provide a comprehensive molecular basis for classifying Hainan tea within the Camellia genus.
A study (DOI:10.48130/abd-0024-0003) published in Agrobiodiversity on 17 May 2024 by Yewei Huang and Shengchang Duan’s team, Yunnan Agricultural University, clarifys the taxonomic position of Hainan tea and underscores the importance for conservation and molecular breeding efforts.
In this study, whole-genome resequencing was performed on 500 tea tree samples collected from four major tea-producing regions of Hainan: Ledong, Qiongzhong, Baisha, and Wuzhishan. These samples included a significant number of ancient tea trees. A total of 6.9 terabytes of raw sequencing data were obtained, which were filtered and aligned with the reference genome (Yunkang 10) to yield a final average alignment rate of 98.98%. After variant calling, 32,334,340 single nucleotide polymorphisms (SNPs) were identified, with the majority located in intergenic regions, and a smaller portion in exonic regions. Phylogenetic analysis using SNP data revealed that Hainan tea samples form a distinct cluster separate from the global Assamica and Sinensis groups, with notable geographic clustering within the Limu Mountain region (LMS) but no clear pattern in other areas. Population structure analysis further confirmed that Hainan tea exhibits a unique genetic composition compared to global varieties. Principal component analysis (PCA) supported these findings, showing that Hainan tea is genetically distinct from Assamica and Sinensis, though it shares some genetic similarities with global Assamica1. Additionally, gene flow analysis suggested limited historical migration between Hainan tea and other tea varieties, reinforcing its distinct genetic lineage. Kinship analysis indicated that close genetic relationships observed in certain Hainan tea samples were influenced by human activities in managed tea gardens. Genetic diversity analysis revealed higher diversity levels in Hainan and LMS populations compared to Assamica and Sinensis, with minimal genetic differentiation between Hainan tea and LMS. These results highlight the unique evolutionary trajectory of Hainan tea, providing valuable insights into its genetic background and offering implications for conservation and breeding strategies.
Hainan tea’s genetic uniqueness and high diversity highlight its potential as a valuable resource for future breeding programs. This study offers a deeper understanding of the evolution of Camellia sinensis and sets the stage for further research into the genetic foundation of Hainan’s remarkable plant life.
###
References
DOI
10.48130/abd-0024-0003
Original Source URL
https://doi.org/10.48130/abd-0024-0003
Funding information
This work was supported by the Hainan Academy of Agricultural Sciences Research Project (HAAS2022KJCX03), Research and Demonstration on Key Technologies of Germplasm Resource Bank Construction and Resource Innovation Utilization of Wuzhishan Big Leaf Tea (ZDYF2024XDNY245) and Monitoring and Analysis of Key Quality Components of Hainan Big Leaf Black Tea and Development and Demonstration of New Standardized Processing Technology (WZSKTPXM202202).
About Agrobiodiversity
Agrobiodiversity is the official journal of Yunnan Agricultural University and published by Maximum Academic Press. Agrobiodiversity is an open access, online-only, rigorously peer-reviewed academic journal focusing on the research and studies related to agriculture and biodiversity, including but not limited to: innovation discovery, theory, and technology of agricultural biodiversity; diversity of agricultural genetic resources; environmental interactions among various crops; interaction between crops and abiotic environment; interaction between crops and microbial environment; research on new composite agricultural technology; exploration of new resource species in agriculture. Agrobiodiversity is dedicated to publishing original research articles, reviews, perspectives, opinions, letters, and editorials with high quality.