ITS rDNA phylogeny of Iranian strains of Cytospora and associated teleomorphs

Abstract

Cytospora spp. and associated teleomorphic species (Ascomycota, Diaporthales, Valsaceae) are among the most common and widespread canker- and dieback-causing fungi on trees, shrubs and herbaceous plants worldwide. From specimens collected all over Iran a total of 114 isolates were morphologically identified, representing 20 Cytospora, one Leucostoma and five Valsa species from 38 plant species. Nine of the identified taxa were new records for Iran, and many new hosts were identified. The phylogenetic relationships of the Iranian strains, along with sequences of 13 reference strains from GenBank, were inferred from ITS1-5.8S-ITS2 nuclear rDNA sequences. Parsimony analysis established five distinct major clades and 12 subclades, which represented accepted species and genera. Some of these subclades corresponded to morphologically based taxonomic concepts of single Cytospora species, while others contained more than one morphospecies. Teleomorphic states were present in six subclades, and most clustered with the corresponding anamorphs. This suggests that morphological and phylogenetic species concepts overlap and that in most cases they are meaningful for correct species identification.

• Cytospora
• ITS
• Leucostoma
• phylogeny
• sequence analysis
• Valsa

We are grateful for the help of Edith Lang, Hans-Heini Vogel and Karsten Rohweder who provided technical assistance, Alex Kocyan who provided advice on data analyses, University of Tehran, Iran, which provided financial support, and Swiss Federal Institute of Technology (ETH Zurich), which hosted Kh.-B. Fotouhifar and provided technical support. We also are indebted to the curator of the herbarium ETH (Z + ZT), Reinhard Berndt, who provided helpful assistance.