Comparative Phylogenetic Analysis for (Aeridinae, Orchidaceae) Based on Six Complete Plastid Genomes.

Lour. (Orchidaceae, Aeridinae) is a group of epiphytic orchids with high ornamental value, mainly distributed in tropical and subtropical forests, that comprises approximately 20 species. The species are of great value in floriculture and garden designing because of their beautiful flower shapes and colors. Although the morphological boundaries of are clearly defined, the relationship between and other closely related genera is still ambiguous in terms of phylogeny. To better understand their phylogenetic relationships, this study used next-generation sequencing technology to investigate the phylogeny and DNA barcoding of this taxonomic unit using genetic information from six plastid genomes. The quadripartite-structure plastomes ranged from 147,244 bp to 148,391 bp and included 120 genes. Among them, 74 were protein coding genes, 38 were tRNA genes and 8 were rRNA genes, while the genes were pseudogenized or lost. Four non-coding mutational hotspots (, Pi > 0.06) were identified. A total of 71-77 SSRs and 19-46 long repeats (>30 bp) were recognized in plastomes, which were mostly located in the large single-copy region. Phylogenetic analysis indicated that was monophylic and sister to . Moreover, our results confirmed that six species can be divided into three major clades. These findings provide assistance for species identification and DNA barcoding investigation in as well as contributes to future research on the phylogenomics of Orchidaceae.