Mycologia Iranica
Volume:10 Issue: 2, Summer and Autumn 2023

Distoseptispora generally is  regarded as a saprobic lignicolous fungal genus and presently comprises 64 species. Of these, 42 of them were found in freshwater and 22 in terrestrial habitats. Most Distoseptispora species are reported from China and Thailand, which are subtropical and tropical regions. In this study, we report Distoseptispora bambusae as a saprobic fungus on decaying leaves of common bamboo (Bambusa vulgaris) based on morphological characteristics and sequence data of the ITS‒rDNA region. Distoseptispora bambusae was described, illustrated, and its morphology and phylogenetic relationships with similar Distoseptispora species were discussed. To the best of our knowledge, this is the first report of D. bambusae on common bamboo for the mycobiota of Iran and the Middle East.

In this study, the phylogeny and taxonomy of Erysiphe sect. Microsphaera was investigated for the first time in Iran. This study was based on morphological examination and rDNA (ITS+ LSU) sequencing. We examined 80 voucher specimens from the Fungus Reference Collection of Herbarium Ministerii Iranici Agriculturae (IRAN) and the University of Guilan Mycological fungarium (including specimens newly collected during 2019–2021). Seventy-nine sequences covering 20 species were generated. E. hyperici was not available for this study. Sequencing of E. begoniicola and E. tortilis failed. Based on our findings, E. coluteae and E. crispula were sequenced for the first time in this study. Records of E. erlangshanensis and E. castaneigena from Iran were rejected. The number of accepted species in sect. Microsphaera increased from 13 in 2009 to 23 in this study. Erysiphe crispula on Astragalus spp. is reported here for the first time, and Syringa vulgaris has been reported as a new host of E. syringae japonicae in Iran. Furthermore, DNA barcodes, colored plates, digital illustrations, and identification keys of all E. sect. Microsphaera in Iran are provided herein.

Ascomycota includes a large number of species that lack a known sexual stage but have a hidden potential for sexual reproduction, among which is Aspergillus flavus, an opportunistic aflatoxin-producing pathogen. The sexual stage of this heterothallic fungus results from crossing between strains with opposite mating types that belong to different vegetative compatibility groups. Here, twenty A. flavus Iranian isolates were investigated for heterothallism and sexual reproduction. The mating type genes MAT1-1 and MAT1-2 were explored using specific primers and multiplex PCR. The results indicated an equal frequency of mating types (1:1) in the investigated A. flavus isolates, indicating heterothallism, and possible sexual reproduction. The cross-cultures on Mixed Cereal Agar (MCA) and Aspergillus Complete Medium (ACM) induced the sexual phase. After 6 to 11 months, 33.16% of the crosses led to sexual reproduction and the sexual reproductive organ of the fungus appeared at the contact lines of the crosses. Scanning Electron Microscopy (SEM) analyses revealed multiple asci and ascospores, which were produced in the pseudoparenchymatous stromata. Ascospore production was more efficient in ACM than in the MCA. Our findings place the Iranian A. flavus in the genus Petromyces, as Petromyces flavus.

Due to the variety of vegetation and high humidity, the Northern provinces of Iran are the habitat of many medicinal mushrooms. Genetic variation of medicinal mushrooms in Iran is poorly studied. 30 isolates of Trametes versicolor were collected from different localities in Guilan, Golestan, and Mazandaran provinces (North of Iran). The genetic diversity was evaluated by ISSR marker. 86 bands were observed using eight polymorphic primers. Cluster analysis showed that the isolates divided into 18 groups at a level of 0.22 similarity coefficient. SI indices were 0.335, 0.305 and 0.217 in Guilan, Golestan, and Mazandaran populations respectively. 96% genetic variation was observed within populations. The diverse geographic origin of the isolates is an influential factor in the high intra-population genetic diversity of the fungus.

In this study, twenty-one isolates of the genus Colletotrichum with straight conidia were isolated from leaf spots on wild Poaceae plants in three provinces of Iran, including East Azarbaijan, Golestan, and Guilan. Based on morphology, the isolates belonged to three morphotypes. Representative isolates were studied by a polyphasic approach, which included morphology, and phylogeny inferred from multi-locus sequences including the nuc rDNA ITS1-5.8S-ITS2 (ITS), partial sequences of the β-tubulin (TUB2), and actin (ACT) genomic regions. Three distinct species were identified namely C. chrysophilum, C. destructivum and C. orientalis.  Colletotrichum chrysophilum and C. orientalis are new records for the Funga of Iran. This study provides new insights into the host range and geographical distribution of these identified species.

The genus Trichoderma consists of globally distributed fungi. Among them, T. harzianum, is one of the most commonly collected Trichoderma species, which had been known as an aggregate species. In the present study, using a Trichoderma selective medium, 20 isolates belonging to 5 Trichoderma species of the Harzianum clad were isolated from soil samples collected from diverse geographical regions of Khorramabad County, Iran. Comparing the cultural and phenotypic criteria combined with molecular tests of the tef1 gene sequences of isolated fungi, five species namely, T. afroharzianum, T. atrobrunneum, T. guizhouense, T. harzianum and T. pholiotae were identified and their descriptions and figures are presented in this paper. T. harzianum had the highest frequency among the 5 species. T. pholiotae is reported for the first time from Iran.

The necrotrophic fungus Parastagonospora nodorum, the causal agent of stagonospora nodorum blotch (SNB), is responsible for significant economic losses of wheat worldwide. Despite the presence of a high number of TF-encoding genes within the genome of P. nodorum, very little is known about their expression profile and their functions during cellular and biological processes. In this study, ten putative TF genes in P. nodorum isolate SN15 were selected, four of which shared homology with well-known fungal TFs involved in pathogenesis, and the other six genes were located in putative secondary metabolite biosynthetic gene clusters (BGCs). The expression profile of these candidate TF genes was investigated using both semi-quantitative and quantitative RT-PCR assays under in vitro and in planta conditions. The results revealed that six candidate TF genes exhibited the highest expression levels in the minimal media lacking both nitrogen and carbon sources as well as during the early stages of infection. These findings suggest that these six candidate TFs may play an important role in the pathogenicity of P. nodorum.

Persian oak is the most important forest tree in Fars province (Iran). In order to identify the composition of Alternaria species associated with healthy and declined Persian oak trees in Fars Province, Iran, fungal isolates were recovered from twigs, trunks and leaves of healthy and declining Persian oak trees from early September to late March 2021-2022. Fungal species were identified based on both morphological and as well as molecular characteristics of the DNA sequence data of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and plasma membrane ATPase genes. In total, 29 Alternaria isolates were obtained, which were identified as Alternaria alternata, Alternaria consortialis and Alternaria chlamydospora. Alternaria alternata showed the highest frequency approximately 51.72% and were isolated from both healthy and declining oak trees. Alternaria chlamydospora and A. consortialis were obtained only from healthy oak trees without declining symptoms with 41.38% and 6.89% frequencies,, respectively. Pathogenicity tests were conducted using all isolates in three replicates. Inoculation of different Alternaria alternata, Alternaria consortialis and Alternaria chlamydospora isolates on Persian oak seedlings did not show any symptoms after 60 days in greenhouse conditions. This is a new report of Alternaria species including A. alternata, A. consortialis and A. chlamydospora as endophytic fungi on Persian oak tree in Fars province of Iran.