Characterization and comparative analysis of the complete chloroplast genome sequence from Prunus avium ‘Summit’

Abstract

Background Sweet cherry (Prunus avium) is one of the most popular of the temperate fruits. Previous studies have demonstrated that there were several haplotypes in the chloroplast genome of sweet cherry cultivars. However, none of chloroplast genome of a sweet cherry cultivar were yet released, and the phylogenetic relationships among Prunus based on chloroplast genome data were unclear. Methods In this study, we assembled and annotated the complete chloroplast genome of a sweet cherry cultivar P. avium ‘Summit’ from high-throughput sequencing data. Gene Ontology (GO) terms were assigned to classify the function of the annotated genes. Maximum likelihood (ML) trees were constructed to reveal the phylogenetic relationships within Prunus species, using LSC (large single-copy) regions, SSC (small single-copy) regions, IR (inverted repeats) regions, CDS (coding sequences), intergenic regions, and whole cp genome datasets, respectively. Results The complete plastid genome was 157, 886 bp in length with a typical quadripartite structure of LSC (85,990 bp) and SSC (19,080 bp) regions, separated by a pair of IR regions (26,408 bp). It contained 131 genes, including 86 protein-coding genes, 37 transfer RNA genes and 8 ribosomal RNA genes. A total of 77 genes were assigned to three major GO categories, including molecular function, cellular component and biological process categories. Comparison with other Prunus species showed that P. avium ‘Summit’ was quite conserved in gene content and structure. The non-coding regions, ndhc-trnV, rps12-trnV and rpl32-trnL were the most variable sequences between wild Mazzard cherry and ‘Summit’ cherry. A total of 73 simple sequence repeats (SSRs) were identified in ‘Summit’ cherry and most of them were mononucleotide repeats. ML phylogenetic tree within Prunus species revealed four clades: Amygdalus, Cerasus, Padus, and Prunus. The SSC and IR trees were incongruent with results using other cp data partitions. These data provide valuable genetic resources for future research on sweet cherry and Prunus species.