The chloroplast genome of Cerasus humilis: Genomic characterization and phylogenetic analysis.

Cerasus humilis is endemic to China and is a new fruit tree species with economic and environmental benefits, with potential developmental and utilization applications. We report the first complete chloroplast genome sequence of C. humilis. Its genome is 158,084 bp in size, and the overall GC content is 36.8%. An inverted repeats (IR) of 52,672 bp in size is separated by a large single-copy (LSC) region of 86,374 bp and a small single-copy (SSC) region of 19,038 bp. The chloroplast genome of C. humilis contains 131 genes including 90 protein-coding genes, 33 transfer RNA genes, and 8 ribosomal RNA genes. The genome has a total 510 simple sequence repeats (SSRs). Of these, 306, 149, and 55 were found in the LSC, IR, and SSC regions, respectively. In addition, a comparison of the boundaries of the LSC, SSC, and IR regions of ten other Prunus species exhibited an overall high degree of sequence similarity, with slight variations in the IR boundary region which included gene deletions, insertions, expansions, and contractions. C. humilis lost the ycf1 gene at the IRA/SSC border and it has the largest ycf1 gene at the IRB/SSC border among these Prunus species, whereas the rps19 gene was inserted at the IRB/LSC junction. Furthermore, phylogenetic reconstruction using 61 conserved coding-protein genes clustered C. humilis with Prunus tomentosa. Thus, the complete chloroplast genome sequence of C. humilis provides a rich source of genetic information for studies on Prunus taxonomy, phylogeny, and evolution, as well as lays the foundation for further development and utilization of C. humilis.