The evolution of fungal epiphytes

Fungal epiphytes are a polyphyletic group found on the surface of plants, particularly on leaves, with a worldwide distribution. They belong in the phylum Ascomycota, which contains the largest known number of fungal genera. There has been little research dating the origins of the common ancestors of fungal epiphytes. This study uses a molecular clock to provide a rough time frame for the origins of fungal epiphytes in the orders Asterinales, Capnodiales, Meliolales, Microthyriales and Zeloasperisporiales. LSU, SSU, RPB1 and RPB2 sequence data from representative strains of the major classes of Ascomycota are used to represent internal calibration points in the phylogenetic tree, to estimate divergence times of fungal epiphyte lineages. The estimated date crowns of fungal epiphytes included in the orders Asterinales, Capnodiales, Meliolales occur in the middle or the end of Jurassic, with Meliolales and Zeloasperisporiales occurring in the Cretaceous. Foliar epiphytes placed in totally unrelated classes evolved as early as the Permian (298.9 to 252.17 Mya) based on sequence data from representative foliar epiphytes and fossil calibrations. The evolution of the most closely related groups of fungi and foliar epiphytes occurred during the Triassic to Jurassic. Phylogenetic relationships, evolution of morphological characters and nutritional mode of foliar epiphytes are discussed. © Guizhou Academy of Agricultural Sciences.