Plastid phylogenomics clarifies broad-level relationships in Bulbophyllum (Orchidaceae) and provides insights into range evolution of Australasian section Adelopetalum

• DOI: 10.3389/fpls.2023.1219354
• Publication Date: 2024-05-24T10:29:06Z
• Authors: Lalita Simpson; Mark A. Clements; Harvey K. Orel; Darren M. Crayn; Katharina Nargar
• Keywords: Pantropical; NdhF; Monophyly; Molecular Phylogenetics; Molecular clock; plant evolution; Orchidaceae

The hyperdiverse orchid genus Bulbophyllum is the second largest of flowering plants and exhibits a pantropical distribution with center diversity in tropical Asia. only section Australasia sect. Adelopetalum . However, phylogenetic placement, interspecific relationships, spatio-temporal evolution this remain largely unclear. To infer broad-level relationships within , genome skimming dataset was generated for 89 samples, which yielded 70 plastid coding regions nuclear ribosomal DNA cistron. For 18 additional Sanger data from two loci ( mat K ycf 1) ITS were added using supermatrix approach. study provided new insights into including evidence non-monophyly sections Beccariana Brachyantha Brachypus Cirrhopetaloides Cirrhopetalum Desmosanthes Minutissima Oxysepala Polymeres Sestochilos Section s.s. formed highly supported clade that resolved as sister group to remainder genus. Divergence time estimations based on relaxed molecular clock model placed origin Early Oligocene (ca. 33.2 Ma) Late 23.6 Ma). Ancestral range BAYAREALIKE identified Australian continent ancestral area Adelopetalum. underwent crown diversification mid-Miocene late Pleistocene, predominantly continental Australia. At least independent long-distance dispersal events inferred eastward New Zealand Caledonia early Pliocene onwards, likely mediated by westerly winds Southern hemisphere. Retraction fragmentation eastern rainforests Miocene onwards are drivers lineage divergence facilitating allopatric speciation.