Characterization of the complete chloroplast genome of Chinese fringetree (Chionanthus retusus)

Chionanthus retusus (Oleaceae) is a valuable plant species native to eastern Asia. In this study, the complete chloroplast genome of C. retusus was assembled based on next generation sequencing. The complete chloroplast of C. retusus is 155,687 bp in length, which is divided into a large single-copy (LSC) region of 86,499 bp and a small single-copy (SSC) region of 17,894 bp, separated by a pair of inverted repeat regions (IRa and IRb), each of 25,647 bp. The genome contains 114 unique genes, including 80 protein-coding genes, 30 tRNA genes, and four ribosomal RNA genes. The overall GC content of the chloroplast genome is 37.8%, whereas the corresponding values of the LSC, SSC, and IR regions are 35.8, 32.0, and 43.2%, respectively. A maximum likelihood phylogenetic analysis showed that C. retusus is closely related to Olea and Hesperelaea with strong support values.