A taxonomic revision of Erysiphe sect. Uncinula (Erysiphaceae, Helotiales) in Iran

Since the publication of the latest monograph of powdery mildews by Braun and Cook in 2012, no comprehensive revision has been done to check the accuracy of the hitherto recorded species of the genus Erysiphe in Iran. In this study, we present a taxonomic revision of Erysiphe sect. Uncinula in Iran using morphological traits of voucher specimens and ITS-LSU rDNA sequence analysis. Thirty-eight voucher specimens were obtained from the University of Guilan Mycological herbarium (fungarium, GUM) and the Fungus Reference Collection of Herbarium Ministerii Iranici Agriculturae (IRAN), as well as newly collected specimens during 2019–2021, were examined morphologically. The ITS sequences were generated for 26 selected specimens, and the LSU sequences were generated for 16 specimens. Two ITS sequences of E. paradoxa (OM574846 and OM574845), as well as ITS and LSU sequences of E. celtidis (OM574855 and OM574834, respectively), were sequenced for the first time in this study. Precise morphological observations and molecular analyses of Iranian specimens changed the number of accepted species of Erysiphe sect. Uncinula from six taxa in 2009 to 10 taxa in 2021. All species identified from Iran are here described and illustrated. A key to species of Erysiphe sect. Uncinula in Iran is also provided.