Chloroplast Genome Analysis Illuminates Two Cornus Species and Family Relationships

Understanding the genetic blueprint of plants is crucial for tracing their evolutionary paths and identifying relationships between species. This study presents a comprehensive analysis of the chloroplast genomes—the genetic material found in plant organelles responsible for photosynthesis—of two species belonging to the genus Cornus: Cornus sanguinea L. and Cornus sericea L.

The complete chloroplast genomes of C. sericea and C. sanguinea were assembled and characterized, measuring 158,244 bp and 158,663 bp, respectively. Both plastomes exhibit a typical circular quadripartite structure, with slight variations in the lengths of the large and small single-copy regions. A total of 131 genes were identified in each cp genome, comprising 86 protein-coding genes, 37 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. Notably, tetra-, penta-, and hexa-nucleotide simple sequence repeats were absent in both genomes.

The study also investigated the taxonomic relationships among the Cornaceae and the closely related families Hydrangeaceae, Nyssaceae, Garryaceae, Curtisiaceae, and Grubbiaceae. Phylogenetic analyses clustered C. sanguinea and C. sericea into a single well-supported clade Cornaceae, reflecting their close relationships with other species in the family, which is consistent with previous studies.

As lead author Nikonorova notes in the paper, "Overall, this study provides new insights into the structure and features of the C. sericea and C. sanguinea cp genomes."