A comparative analysis of the complete chloroplast genomes of three Chrysanthemum boreale strains.

The sizes of the complete chloroplast genomes of the C. boreale strains were 151,012 bp (strain 121002), 151,098 bp (strain IT232531) and 151,010 bp (strain IT301358). Each genome contained 80 unique protein-coding genes, 4 rRNA genes and 29 tRNA genes. Comparative analyses revealed a high degree of conservation in the overall sequence, gene content, gene order and GC content among the strains. We identified 298 single nucleotide polymorphisms (SNPs) and 106 insertions/deletions (indels) in the chloroplast genomes. These variations were more abundant in non-coding regions than in coding regions. Long dispersed repeats and simple sequence repeats were present in both coding and noncoding regions, with greater frequency in the latter. Regardless of their location, these repeats can be used for molecular marker development. Phylogenetic analysis revealed the evolutionary relationship of the species in the Anthemideae tribe. The three complete chloroplast genomes will be valuable genetic resources for studying the population genetics and evolutionary relationships of Asteraceae species.