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Oak decline is a complex disorder that seriously threatens the survival of Zagros forests. In an extensive study on taxonomy and pathology of fungi associated with oak decline in the central and northern part of Zagros forests, 462 fungal isolates were obtained from oak trees showing canker, gummosis, dieback, defoliation, and partial or total death symptoms. Based on inter-simple sequence repeat (ISSR) fingerprinting patterns, morphological characteristics, and sequences of ribosomal DNA (28S rDNA and ITS) and protein coding loci (acl1, act1, caM, tef-1a, rpb1, rpb2, and tub2), 24 fungal species corresponding to 19 genera were characterized. Forty percent of the isolates were placed in eight coelomycetous species from seven genera, namely, Alloeutypa, Botryosphaeria, Cytospora, Didymella, Gnomoniopsis, Kalmusia, and Neoscytalidium. Of these, four species are new to science, which are introduced here as taxonomic novelties: Alloeutypa iranensis sp. nov., Cytospora hedjaroudei sp. nov., Cytospora zagrosensis sp. nov., and Gnomoniopsis quercicola sp. nov. According to pathogenicity trials on leaves and stems of 2-year-old Persian oak (Quercus brantii) seedlings, Alternaria spp. (A. alternata, A. atra, and A. contlous), Chaetomium globosum, and Parachaetomium perlucidum were recognized as nonpathogenic. All coelomycetous species were determined as pathogenic in both pathogenicity trials on leaves and seedling stems, of which Gnomoniopsis quercicola sp. nov., Botryosphaeria dothidea, and Neoscytalidium dimidiatum were recognized as the most virulent species followed by Biscogniauxia rosacearum. [ABSTRACT FROM AUTHOR]

Two phytotoxic furan derivatives were isolated, together with the well-known fungal and plant phytotoxin tyrosol, from the culture filtrates of Stilbocrea macrostoma. This fungal pathogen isolated from Quercus brantii trees induced wood necrosis and decline symptoms on the host plant in Iran. The two furan derivatives, isolated for the first time from Stilbocrea macrostoma, were identified by spectroscopic methods (essentially 1 D and 2 D 1H and 13C NMR and ESIMS spectroscopy) as 5-hydroxymethylfuraldehyde and 2,5-dihydroxymethylfuran. The phytotoxic activity of the three metabolites was evaluated by leaf puncture assay on holm oak (Quercus ilex L.) and tomato (Lycopersicon esculentum L.) leaves. All compounds induced necrosis on holm oak leaves while very low toxicity was showed against tomato leaves. The two furan derivatives were more toxic than tyrosol and particularly 5-hydroxymethylfuraldehyde was the most phytotoxic compound. [ABSTRACT FROM AUTHOR]