Comparative chloroplast genomics of Limeum (Limeaceae) species: New insights into genome evolution and phylogenomic implications
Limeum is the sole genus of Limeaceae, comprising approximately 20 species distributed across Africa, Southwest Asia, and India. However, genomic resources for the family are limited, and phylogenetic relationships within the genus remain poorly understood. In this study, we sequenced, assembled, and analyzed the complete chloroplast genomes of six Limeum species to investigate their genomic characteristics and phylogenetic relationships. The chloroplast genomes ranged from 156,354 bp to 160,377 bp in length and exhibited the typical quadripartite structure. Each genome contained 131 genes, consisting of 86 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Comparative analyses identified 455 tandem repeats and 616 simple sequence repeats, revealing 16 highly variable regions that may serve as potential molecular markers for future studies. Phylogenetic analyses based on complete chloroplast genome sequences strongly supported the monophyly of Limeum and robustly resolved interspecific relationships within the genus. These results provide the first comprehensive plastome dataset for Limeum and a valuable genomic resource for species identification, genetic diversity assessment, phylogenetic reconstruction, and evolution studies of Limeum and the family Limeaceae.