Tao Yanlan, Huang Lichao, Chen Hongyu, Luo Yiju, Tang Rong, Li Faying, Lan Zengquan
College of Forestry, Southwest Forestry University, Yunnan, China.
Ancient Tea Tree Research Centre, Southwest Forestry University, Yunnan, China.
PLoS One. 2025 Jul 31;20(7):e0328658. doi: 10.1371/journal.pone.0328658. eCollection 2025.
Dali tea (Camellia taliensis), serving as a primitive wild species within the section Thea, represents a crucial genetic source for the domestication of Pu-erh tea (C. sinensis var. assamica) due to its strong stress tolerance and unique biochemical composition. It is of key value for the conservation of tea genetic resources and breeding innovation. Utilizing the SLAF-seq (Specific-Locus Amplified Fragment Sequencing) technique, this study systematically analyzed the genetic diversity and evolutionary relationships among five geographic populations (16 C. taliensis and 4 C. sinensis var. assamica accessions) within the Lancang River basin. Results revealed significant genetic differentiation among the C. taliensis populations. Pronounced genetic isolation was observed between the Lincang Daxueshan and Dali Nanjian populations. Localized gene introgression occurred between wild C. taliensis (Nanjian population) and C. sinensis var. assamica.The wild Lincang Daxueshan population formed a monophyletic clade at the base of the phylogenetic tree, exhibiting strong genetic isolation and high differentiation levels (Fst = 0.364) but low genetic diversity. In contrast, the cultivated population (Banna Germplasm Repository) displayed a mixed genetic background, with wild genetic components constituting only 50%-60%. The Lincang Daxueshan wild population showed a low minor allele frequency (MAF = 0.204) and a mild inbreeding coefficient (Fis = 0.09), indicating a potential risk of genetic erosion. Conversely, the Banna Germplasm Repository population exhibited the highest genetic diversity (Shannon Index = 0.318), highlighting the effectiveness of ex situ conservation and its potential as a vital gene donor for tea breeding. This study underscores the unique status of the upper Lancang River basin in Yunnan as a core conservation area for C. taliensis genetic diversity. We propose strategies of "delineating priority zones for in situ conservation" and "facilitating inter-population germplasm exchange," providing a molecular basis for conserving wild tea resources and breeding for stress resistance. Employing high-density SNP markers, we obtained 5,182,931 loci with an average sequencing depth of 19.30x. This enabled quantification of gene flow between wild and cultivated populations (Nm = 0.18) and clarified the contribution of introgressive domestication to the genetic makeup of cultivated tea. These findings provide a theoretical foundation for understanding interspecific interaction mechanisms in tea plant evolution and hold significant implications for promoting regional ecological conservation and biodiversity maintenance.
大理茶（Camellia taliensis）作为茶组内的原始野生种，因其较强的抗逆性和独特的生化成分，是普洱茶（C. sinensis var. assamica）驯化的关键遗传资源。它对于茶遗传资源的保护和育种创新具有重要价值。本研究利用SLAF-seq（特异性位点扩增片段测序）技术，系统分析了澜沧江流域五个地理种群（16份大理茶和4份普洱茶种质）的遗传多样性和进化关系。结果表明大理茶种群间存在显著的遗传分化。在临沧大雪山和大理南涧种群之间观察到明显的遗传隔离。野生大理茶（南涧种群）与普洱茶之间发生了局部基因渐渗。野生临沧大雪山种群在系统发育树基部形成一个单系分支，表现出强烈的遗传隔离和高分化水平（Fst = 0.364），但遗传多样性较低。相比之下，栽培种群（版纳种质库）呈现混合遗传背景，野生遗传成分仅占50%-60%。临沧大雪山野生种群显示出较低的次要等位基因频率（MAF = 0.204）和轻度的近交系数（Fis = 0.09），表明存在遗传侵蚀的潜在风险。相反，版纳种质库种群表现出最高的遗传多样性（香农指数 = 0.318），突出了迁地保护的有效性及其作为茶育种重要基因供体的潜力。本研究强调了云南澜沧江上游流域作为大理茶遗传多样性核心保护区的独特地位。我们提出了“划定原地保护优先区域”和“促进种群间种质交换”的策略，为野生茶资源保护和抗逆育种提供了分子依据。利用高密度SNP标记，我们获得了5,182,931个位点，平均测序深度为19.30x。这使得能够量化野生和栽培种群之间的基因流（Nm = 0.18），并阐明渐渗驯化对栽培茶遗传组成的贡献。这些发现为理解茶树进化中的种间相互作用机制提供了理论基础，对促进区域生态保护和生物多样性维持具有重要意义。
