Catalogue of fungi in China 6: Rhytismataceae on twigs of Rhododendron

Members of the Rhytismataceae (Rhytismatales) are found all over the world, which include saprobes, endophytes, and plant pathogens. They can infect a wide variety of host plants and cause plant diseases. As one of the most preferred hosts of rhytismatalean fungi, a total of 90 species of Rhytismatales in 21 genera are known by Rhododendron spp. worldwide, including 53 species on twigs and 37 species on leaves. In this research, a sum of 46 specimens were collected from the twigs of Rhododendron species in China. Subsequently, based on multi-gene phylogenetic analyses using molecular sequence data from the internal transcribed spacer (ITS) region, the large subunit of the ribosomal RNA gene (nrLSU), the mitochondrial small subunit (mtSSU), and morphological characteristics, three new genera were proposed (Neolophodermium, Truncomyces, and Virgamyces), and 21 species in 11 genera of Rhytismataceae were delimited, which include 18 new species and three new combinations. This study complements the diversity of Rhytismataceae on twigs of Rhododendron. An integrated taxonomic approach includes the evidence for morphological characteristics, the ecological data, and the phylogenetic analyses based on multiple loci and was demonstrated, which can be defined a natural classification of Rhytismataceae on the genus level.