Morphology and Phylogeny Reveal Three New Species of Cytospora Associated with Tree Cankers in China

Cytospora (Cytosporaceae, Diaporthales) is a fungal genus that usually inhabits plants as endophytes, saprobes, as well as pathogens. Species of this genus are characterized by possessing allantoid hyaline conidia and ascospores. Samples with typical Cytospora canker symptoms on Prunus davidiana, P. padus and Salix sp. were collected in Tibet and Xinjiang, China. Species were identified using both morphological and molecular approaches of combined loci of internal transcribed spacer region rDNA (ITS), the partial actin (act) region, RNA polymerase II second largest subunit (rpb2), the translation elongation factor 1-alpha (tef1) gene and the partial be-ta-tubulin (tub2) gene. Six isolates in the present study formed three distinct clades from previously known species. Cytospora hejingensis sp. nov. from Salix sp., C. jilongensis sp. nov. from P. davidiana and C. kunsensis from P. padus were proposed herein. The current study improves the understanding of species concept in Cytospora.