ORIGINAL ARTICLE Taxonomic study on Alternaria sections Infectoriae and Pseudoalternaria associated with black (sooty) head mold of wheat and barley in Iran Alireza Poursafar 1 & Youbert Ghosta 2 & Alexandra S. Orina 3 & Philipp B. Gannibal 3 & Mohammad Javan-Nikkhah 1 & Daniel P. Lawrence 4 Received: 8 June 2017 /Revised: 27 October 2017 /Accepted: 30 October 2017 # German Mycological Society and Springer-Verlag GmbH Germany, part of Springer Nature 2017 Abstract During the spring and summer of 2014 and 2015, wheat and barley fields in the Iranian provinces of Golestan and Alborz showed a high incidence of symptoms of black (sooty) head mold of wheat and barley. The isolation results revealed that Alternaria was associated with these symptoms. One hundred and forty isolates were collected and morphologically characterized based on the development of conidial chains with primary, secondary, and tertiary branching patterns, consistent with the three-dimensional sporulation complexity of members of Alternaria in sections Infectoriae and Pseudoalternaria. Subsequently, 16 Alternaria isolates exhibiting high morphological diversity were characterized based on extensive morphological and molecular compari- sons. Phylogenetic analyses of three loci [ITS, glyceraldehyde 3-phosphate dehydrogenase (gpd), and plasma membrane ATPase (ATPase)] revealed that 15 isolates belonged to section Infectoriae but could not be assigned to phylogenetic species and one isolate represents a new species, Alternaria kordkuyana sp. nov., in section Pseudoalternaria. Morphological assessments revealed a high degree of variation among section Infectoriae isolates and that A. kordkuyana has significant morphological differences as compared to the three other species currently described in section Pseudoalternaria. Keywords Alternaria . Sooty head mold . Taxonomy . Alternaria kordkuyana sp. nov. . Section Pseudoalternaria Introduction Alternaria Nees (1816) is a speciose fungal genus with world- wide distributions and diverse ecological lifestyles, including saprobic, parasitic, and endophytic species. The taxonomic va- lidity of the genus Alternaria has been questioned since its inception. Species delimitiation and identification can be very difficult due to the great morphological diversity within this pleomorphic genus, the lack of reliable morphological characters at the species level, as well as a large number of host plant associations (Farr et al. 1989; Rotem 1994; Thomma 2003). Species identification in Alternaria has been traditionally based on morphological characters of co- nidia and associations with host plants (Neergaard 1945; Joly 1964; Ellis 1971, 1976; Simmons 2007). Although more than 1100 names can be found in the literature, only about 280 morphospecies have been accepted (Simmons 2007 ). Previously, Alternaria species were organized into a number of morphological species-groups based on shared sporula- tion patterns and conidial morphology, each of which was typified by a representative species (Simmons 1992, 1995; Simmons and Roberts 1993). Several DNA-based efforts have provided strong support for Alternaria morphological species-group concepts (Pryor and Gilbertson 2000; Pryor and Michailides 2002 ; Chou and Wu 2002 ; de Hoog and Horre 2002; Pryor and Bigelow 2003; Peever et al. Section Editor: Gerhard Rambold Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11557-017-1358-1) contains supplementary material, which is available to authorized users. * Daniel P. Lawrence dlawrence@ucdavis.edu 1 Department of Plant Protection, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran 2 Department of Plant Protection, Faculty of Agriculture, University of Urmia, Urmia, Iran 3 Laboratory of Mycology and Phytopathology, All-Russian Institute of Plant Protection, Shosse Podelskogo 3, Saint Petersburg 196608, Russia 4 Department of Plant Pathology, University of California, Davis, CA 95616, USA Mycological Progress https://doi.org/10.1007/s11557-017-1358-1