The complete chloroplast genome of Photinia davidsoniae: molecular structures and comparative analysis

Photinia davidsoniae is a common ornamental arbor in the genus Photinia (family Rosaceae). Here, we sequenced and assembled the complete plastome of P. davidsoniae using the next-generation DNA sequencing technology. And we then compared it with nine Photinia species using a range of bioinformatics software tools. The ten plastomes had sizes ranging from 159,230 bp for P. beckii to 160,346 bp for P. davidsoniae. They all had a conservative quartile structure. It contained two single-copy regions: a large single-copy (LSC) region, a small single-copy (SSC) region, and a pair of inverted repeat (IR) regions. Each of the plastomes encoded 113 unique genes, including 79 protein-coding genes, four rRNA genes, and 30 tRNA genes. Furthermore, we detected six hypervariable regions (matK-rps16, rpoB-trnC, trnT-psbD, ndhC-trnV, psbE-petL, ndhF-rpl32-trnL), which could be used as potential molecular markers. We constructed two phylogenetic trees with plastomes or concatenated protein sequences of 25 species of 8 genera of Rosaceae. The tree constructed with complete plastomes has much stronger support. The results placed P. davidsoniae in the upper part of the phylogenetic tree. It shows that P. davidsoniae and P. lanuginosa are closely related. In summary, the plastomes of Photinia are conserved overall but carry significant minor variations, as expected. The results will be indispensable for distinguishing species, understanding the interspecific diversity, and elucidating the evolutionary processes of Photinia species.