Eggplant (Solanum melongena L.) is an economically important solanaceous crop in Iran with fruits used for food and traditional medicine. Despite the importance of Alternaria leaf spot and blight disease of solanaceous crops which is commonly seen in the fields, our knowledge about the causal agents on eggplant is limited. In this study, a set of large-spored Alternaria isolates was recovered from eggplant with leaf spot and blight symptoms in Somehsara region, Guilan province, Iran. All recovered isolates shared conspicuous morphological characteristics e.g. production of large, solitary conidia with several transverse disto- and eusepta and long tapering filamentous beak resemble those seen in the members of Alternaria section Porri. Multi-locus phylogenetic analyses based on the internal transcribed spacer region of nrDNA (ITS-rDNA) and parts of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), second largest subunit of RNA Polymerase II (RPB2), translation elongation factor 1-alpha (TEF1-α) and Alternaria major allergen (Alt a 1) gene sequences provided further evidence supporting not only their exact placement in Alternaria sect. Porri, but also in a distinct lineage representing a new species. The new species was named, described and illustrated herein as Alternaria guilanica sp. nov.. The phylogenetic and morphological comaprisions of the new species with other closely related species were also provided. Pathogenicity test conducted for the new strains revealed that they were capable to induce disease symptoms on eggplant leaves under greenhouse conditions, and re-isolation of the inoculated isolates confirmed Koch’s postulates.

Alternaria section Panax currently includes seven species which are characterized by simple or branched and short to moderately long primary conidiophores as well as by solitary to short simple or branched chains of conidia with moderate to relatively long secondary conidiophores. Two species within the section have been reported to have sexual morphs. During the study of fungi on overwintered stems of Serratula coriacea Fisch. & C.A.Mey. (Asteraceae) from different regions of Urmia, West Azarbaijan Province, Iran, 26 isolates (16 from conidia and 10 from single ascospores) representing Alternaria characteristics were isolated and studied taxonomically. All the studied isolates formed sexual morph on PDA, PCA, V8–A, and HA media after 2 months incubation in the dark at 4 ºC and fully matured after 3 months. Based on morphological characteristics of sexual and asexual morphs and multiple gene sequences analyses (ITS-rDNA, GAPDH, RPB2 and TEF), the newly studied isolates represented a new species in Alternaria section Panax, which is described and illustrated here as Alternaria hedjaroudei. Alternaria hedjaroudei is phylogenetically close to A. avenicola, A. calycipyricola and A. photistica but it can be distinguished morphologically based on the formation of short chains of conidia (2–3 in a chain), absence of chlamydospores, smaller conidia size, relatively short secondary conidiophores, and fewer transverse septa in mature ascospores. Detailed morphological comparisons with other species in the section Panax are provided.