Chloroplast Genome Analysis and Phylogenetics of Camellia Species

Camellia, a genus of more than 200 species valued for tea, ornamentals and seed oil, has long presented taxonomic and phylogenetic challenges owing to frequent hybridisation and polyploidy. Chloroplast genome analysis offers a conserved yet sufficiently variable marker system to resolve interspecific relationships, trace domestication routes and support conservation strategies. Typical chloroplast genomes in Camellia are circular molecules of approximately 156–158 kb arranged in a quadripartite structure comprising two inverted repeats separated by large and small single-copy regions. Comparative genomics across species reveals high overall structural conservation alongside discrete hypervariable regions and simple sequence repeats that serve as molecular markers. Phylogenetic reconstructions based on complete chloroplast sequences have clarified monophyletic lineages, identified sister-group relationships among cultivars and wild relatives, and highlighted areas where current taxonomy may require revision. These insights underpin breeding programmes, germplasm management and the elucidation of evolutionary processes within this economically and ecologically important genus.

Research from Nature Portfolio

Recent studies have sequenced and assembled nine complete chloroplast genomes representing key Camellia accessions, including multiple varieties of C. japonica and C. petelotii. Genome lengths were tightly conserved around 156,580–157,002 bp, with identical counts of protein-coding genes and only minor variation in tRNA and rRNA content. Structural analyses confirmed the quadripartite organisation without large inversions or rearrangements. Five hypervariable intergenic and coding regions were pinpointed as robust molecular markers for species and cultivar discrimination. Phylogenetic reconstruction incorporating 82 Camellia accessions delineated clear sister-group relationships among popular C. japonica varieties and revealed a close genetic affinity between C. petelotii and certain ornamental cultivars. These findings provide a refined framework for cultivar authentication, conservation prioritisation and deeper understanding of lineage diversification within the genus.

Chloroplast Genome Analysis and Phylogenetics of Camellia Species publication trend

The graph below shows the total number of articles in chloroplast genome analysis and phylogenetics of camellia species across all publications each year (not limited to Nature Index journals).

Technical terms

Chloroplast genome: The circular DNA molecule within chloroplasts encoding photosynthesis-related and housekeeping genes.

Quadripartite structure: Organisation of the chloroplast genome into two inverted repeats and two single-copy regions.

Inverted repeats (IRs): Two identical sequences in opposite orientation that separate single-copy regions and contribute to genome stability.

Simple sequence repeats (SSRs): Short tandemly repeated motifs useful as highly polymorphic molecular markers.

Hypervariable region: Genome segment exhibiting elevated sequence divergence, suitable for species discrimination.

Phylogenetic tree: A branching diagram representing inferred evolutionary relationships among taxa.

Monophyletic group: A set of taxa that includes a common ancestor and all its descendants.

References

1. Nine complete chloroplast genomes of the Camellia genus provide insights into evolutionary relationships and species differentiation. Scientific Reports (2025).
2. Complete chloroplast genomes of 13 species of sect. Tuberculata Chang (Camellia L.): genomic features, comparative analysis, and phylogenetic relationships. BMC Genomics (2024).
3. Comparison of the Chloroplast Genome Sequences of 13 Oil-Tea Camellia Samples and Identification of an Undetermined Oil-Tea Camellia Species From Hainan Province. Frontiers in Plant Science (2022).
4. Exploring the evolutionary characteristics between cultivated tea and its wild relatives using complete chloroplast genomes. BMC Ecology and Evolution (2021).