Taxonomic revision of Neodidymelliopsis with N. cynanchi sp. nov., associated with Cynanchum sibiricum leaf spot in Xinjiang, China

During surveys of plant pathogens in the desert regions of Xinjiang Province, China, a leaf spot was observed on Cynanchum sibiricum. The suspected fungus was isolated and identified using morphology and molecular phylogeny. Morphologically, the fungus was similar to Neodidymelliopsis species. Phylogenetic analyzes of combined internal transcribed spacer (ITS); the large subunit of the ribosomal rDNA (LSU); RNA polymerase II the second largest subunit (rpb2), and β-tubulin gene (tub2) sequences showed that our isolates formed a distinct monophyletic lineage in Neodidymelliopsis. This new clade is identified as Neodidymelliopsis cynanchi sp. nov. based on the phylogenetic and morphological evidence. In addition, N. urticae is synonymized with N. cannabis based on morphology and phylogeny. Furthermore, we emphasize that in-depth revisions are required to assure the taxonomic status of N. sambuci, N. tinkyukuku and N. salvia. This is the first report of Neodidymelliopsis species associated with C. sibiricum leaf spot. The results expand our knowledge of Didymellaceae taxa and microfungi associated with desert environments in China.