Insights into comparative genomics, structural features, and phylogenetic relationship of species from Eurasian and its related genera (Asteraceae: Astereae) based on complete chloroplast genome.

L. is an economically and phylogenetically important genus in the tribe Astereae. Here, the complete plastomes of the eight species were assembled and characterized using next-generation sequencing datasets. The results indicated the complete plastomes of had a quadripartite structure. These genomes were 152,045-152,729 bp in length and contained 132-133 genes, including 87 protein-coding genes, 37-38 tRNA genes, and eight rRNA genes. Expansion or contraction of inverted repeat regions and forward, palindromic, complement, and reverse repeats were detected in the eight species. Additionally, our analyses showed the richest type of simple sequence repeats was A/T mononucleotides, and 14 highly variable regions were discovered by analyzing the border regions, sequence divergence, and hotspots. Phylogenetic analyses indicated that 27 species in Astereae were clustered into six clades, i.e., A to D, North American, and outgroup clades, and supported that the genera , , and are nested within . The results indicated the clades B to D might be considered as genera. Divergence time estimate showed the clades A, B, C, and D diverged at 23.15 Mya, 15.13 Mya, 24.29 Mya, and 21.66 Mya, respectively. These results shed light on the phylogenetic relationships of and provided new information on species identification of and its related genera.