Comparative analyses of chloroplast genomes in ‘Red Fuji’ apples: low rate of chloroplast genome mutations

BACKGROUND: Fuji is a vital apple cultivar, and has been propagated clonally for nearly a century. The chloroplast genome variation of Fuji apples in China has not been investigated. METHODS: This study used next-generation high-throughput sequencing and bioinformatics to compare and analyze the chloroplast genome of 24 Red Fuji varieties from nine regions in China. RESULTS: The results showed that the 24 chloroplast genomes were highly conserved in genome size, structure, and organization. The length of the genomes ranged from 160,063 to 160,070 bp, and the GC content was 36.6%. Each of the 24 chloroplast genomes encoded 131 genes, including 84 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The results of repeat sequence detection were consistent; the most common sequence was forward repeats (53.1%), and the least common sequence was complementary repeats (4.1%). The chloroplast genome sequence of Red Fuji was highly conserved. Two indels were detected, but the PI value was 0, and there were no SNP loci. The chloroplast genome variation rate of Red Fuji was low.