Uneven distribution of mating type alleles in Iranian populations of Cercospora beticola, the causal agent of Cercospora leaf spot disease of sugar beet

Cercospora beticola, the causal agent of Cercospora leaf spot disease on sugar beet, is thought to be exclusively asexual because no teleomorph has yet been found. The possibility of a clandestine sexual cycle in the Iranian population of Cercospora beticola was evaluated by analyzing the distribution and frequency of the mating type alleles on a microspatial and a macrogeographical scale. A total of 89 single-conidial Cercospora beticola isolates were obtained from sugar beet fields in the Moghan, the Talesh and the Khoy regions. The isolates were identifed using a Cercospora beticola-specifc primer set in a PCR assay. A multiplex PCR method using previously designed mating type primers was used to study the distribution and the frequency of the mating type alleles. All isolates showed either the 805-bp fragment or the 442-bp fragment of the MAT1-1 and MAT1-2 genes, but no isolate had both fragments. The distribution of the mating type genes in the sampled areas was uneven. From three sugar beet fields sampled in the Moghan region, two fields had only MAT1-1 isolates; while in the third field all isolates had only the MAT1-2 allele. In the Talesh region only MAT1-1 isolates occurred, and in the Khoy region the mating type alleles were uniformly distributed amongst the isolates. The skewed distribution of mating type alleles in Northwestern Iran was in line with the lack of a sexual cycle for this species and may also indicate that sugar fields in the Moghan region were infected by C. beticola populations of different origins

Biological and molecular characterisation of Pilidium lythri, an emerging strawberry pathogen in Iran

Strawberry production is hampered by numerous biotic factors including fungal pathogens. Symptoms of dark brown necrotic lesions on fruits, stems and leaves were observed in a survey of strawberry fields in the Kurdistan province of Iran. Symptomatic plant tissues were collected and several fungal isolates were recovered from these tissues. Based on a combination of morphological characteristics and sequence data for ITS and LSU ribosomal DNA, the isolates were identified as Pilidium lythri (previously named P. concavum or Hainesia lythri). A pathogenicity assay confirmed that all new isolates induced symptoms resembling those observed in the field, as well as two P. lythri isolates from olive included in the assay; no significant disease incidence or severity differences were detected between isolates. This is the first report of P. lythri on strawberry in Iran. Genetic diversity between Pilidium lythri isolates from strawberry (18 isolates) and olive (two isolates) was evaluated using RAPD and M13 markers. No polymorphism was detected within and among the isolates, indicating limited genetic variability probably due to lack of recombination events and/or recent introduction. Given recent outbreaks and the presence of the pathogen in most strawberry growing areas in the Kurdistan province, quickly applied and appropriate management programmes are necessary to prevent spread of the disease

Uneven distribution of mating type alleles in Iranian populations of <I>Cercospora beticola</I>, the causal agent of Cercospora leaf spot disease of sugar beet

Cercospora beticola, the causal agent of Cercospora leaf spot disease on sugar beet, is thought to be exclusively asexual because no teleomorph has yet been found. The possibility of a clandestine sexual cycle in the Iranian population of Cercospora beticola was evaluated by analyzing the distribution and frequency of the mating type alleles on a microspatial and a macrogeographical scale. A total of 89 single-conidial Cercospora beticola isolates were obtained from sugar beet fields in the Moghan, the Talesh and the Khoy regions. The isolates were identifed using a Cercospora beticola-specifc primer set in a PCR assay. A multiplex PCR method using previously designed mating type primers was used to study the distribution and the frequency of the mating type alleles. All isolates showed either the 805-bp fragment or the 442-bp fragment of the MAT1-1 and MAT1-2 genes, but no isolate had both fragments. The distribution of the mating type genes in the sampled areas was uneven. From three sugar beet fields sampled in the Moghan region, two fields had only MAT1-1 isolates; while in the third field all isolates had only the MAT1-2 allele. In the Talesh region only MAT1-1 isolates occurred, and in the Khoy region the mating type alleles were uniformly distributed amongst the isolates. The skewed distribution of mating type alleles in Northwestern Iran was in line with the lack of a sexual cycle for this species and may also indicate that sugar fields in the Moghan region were infected by C. beticola populations of different origins

New secondary metabolites produced by the phytopathogenic fungus Wilsonomyces carpophilus

wo new metabolites possessing the unusual 1-oxa-7-azaspiro[4.4]non-2- ene-4,6-dione core (2, 3) along with the recently described pseurotin A3 (1) were isolated from the pathogenic fungus Wilsonomyces carpophilus(previously named Stigmina carpophila). The producer organism was obtained from Prunus armeniaca collected in Iran and was identified by morphological and molecular phylogenetic methods. The structures of the isolated compounds were elucidated on the basis of extensive NMR spectroscopic analysis, high-resolution mass spectrometry and ECD analysis. The compounds were screened for their antimicrobial, cytotoxic, nematicidal and biofilm inhibition activities but, no significant effect was observed. To the best of our knowledge, this is the first report on the isolation of secondary metabolites produced by W. carpophilus

Pseudocercospora sophoricola M. Bakhshi, Arzanlou, sp. nov.

Pseudocercospora sophoricola M. Bakhshi, Arzanlou, Babai-ahari & Crous, sp. nov. (Fig. 7) MycoBank MB 809998 Type:— IRAN. Zanjan Province: Tarom, Guilankeshe, on Sophora alopecuroides L. (Fabaceae), October 2011, M. Bakhshi (holotype IRAN 16463 F, culture ex-type CCTU 1037 = CBS 136020). Description in planta:— Leaf spots distinct, amphigenous, circular to subcircular, 1–6 mm diam., pale brown in centre, with raised, dark brown to black border. Mycelium internal. Caespituli predominantly hypophyllous, dark brown on leaves. Stromata moderately developed, substomatal to intraepidermal, semi-immersed, globular, 10–30 μm diam. Conidiophores medium brown, arranged in moderately dense fascicles, smooth, unbranched, straight, doliiform or lageniform to short cylindrical, 0–1-septate, (8–)13–16(–22) × (3–)4.5–5(–6) μm, predominantly reduced to conidiogenous cells, apex subtruncate. Conidiogenous cells medium brown, smooth, proliferating sympodially, tapering to flat-tipped apical loci, loci unthickened to slightly thickened and somewhat darkened, 1–3 μm diam. Conidia solitary, medium to dark brown, guttulate, thick-walled, sometimes constricted at septa, subcylindrical to obclavate, apex obtuse to sub obtuse, base obconically truncate, straight to gently curved, conspicuously 1–8-septate, (20–)50–70(–110) × (2.5–)3.5–4(–5) μm; hila unthickened to slightly thickened and somewhat darkened and refractive, 1–2.5 μm diam. Cultural characteristics:— Colonies on MEA slow growing, reaching 15 mm diam. after 20 days at 25 ºC in the dark; surface velvety, smooth to folded, erumpent with sparse aerial mycelium and even margins. Dark brown to black on the surface, black underneath. Habitat/Distribution:— Known to inhabit Sophora alopecuroides, Zanjan Province, Iran. Etymology:— Named after the host genus from which it was collected, Sophora. Other material examined:— IRAN. Zanjan Province: Tarom, Guilankeshe, on Sophora alopecuroides, October 2011, M . Bakhshi (CCTU 1037.2). Notes:— Pseudocercospora sophoricola must be regarded as a new species based on its distinct phylogenetic position (Fig. 2). In the individual gene trees, it is distinguished in the ITS (sister taxon to P. ocimi-basilici), ACT (sister taxon to P. udagawana) and TEF1-α (sister taxon to P. udagawana) phylogenies. In the combined tree (Fig. 2), it is a sister taxon to P. udagawana. Pseudocercospora sophoricola is morphologically well distinguished from P. sophorae (Guo & Liu 1991) in having narrower stromata, wider conidiophores which are mostly reduced to conidiogenous cells, slightly thickened and somewhat darkened conidiogenous loci and medium to dark brown, somewhat wider and longer, distinctly septate conidia. Furthermore, P. sophorae forms in vivo superficial hyphae with solitary conidiophores. This is the first species of the genus Pseudocercospora described from Sophora alopecuroides.Published as part of Bakhshi, Mounes, Arzanlou, Mahdi, Babai-Ahari, Asadollah, Groenewald, Johannes Z. & Crous, Pedro W., 2014, Multi-gene analysis of Pseudocercospora spp. from Iran, pp. 245-264 in Phytotaxa 184 (5) on page 256, DOI: 10.11646/phytotaxa.184.5.1, http://zenodo.org/record/514680

Novel primers improve species delimitation in Cercospora

The genus Cercospora includes many important plant pathogens that are commonly associated with leaf spot diseases on a wide range of cultivated and wild plant species. Due to the lack of useful morphological features and high levels of intraspecific variation, host plant association has long been a decisive criterion for species delimitation in Cercospora. Because several taxa have broader host ranges, reliance on host data in Cercospora taxonomy has proven problematic. Recent studies have revealed multi-gene DNA sequence data to be highly informative for species identification in Cercospora, especially when used in a concatenated alignment. In spite of this approach, however, several species complexes remained unresolved as no single gene proved informative enough to act as DNA barcoding locus for the genus. Therefore, the aims of the present study were firstly to improve species delimitation in the genus Cercospora by testing additional genes and primers on a broad set of species, and secondly to find the best DNA barcoding gene(s) for species delimitation. Novel primers were developed for tub2 and rpb2 to supplement previously published primers for these loci. To this end, 145 Cercospora isolates from the Iranian mycobiota together with 25 additional reference isolates preserved in the Westerdijk Fungal Biodiversity Institute were subjected to an eight-gene (ITS, tef1, actA, cmdA, his3, tub2, rpb2 and gapdh) analysis. Results from this study provided new insights into DNA barcoding in Cercospora, and revealed gapdh to be a promising gene for species delimitation when supplemented with cmdA, tef1 and tub2. The robust eight-gene phylogeny revealed several novel clades within the existing Cercospora species complexes, such as C. apii, C. armoraciae, C. beticola, C. cf. flagellaris and Cercospora sp. G. The C. apii s. lat. isolates are distributed over three clades, namely C. apii s. str., C. plantaginis and C. uwebrauniana sp. nov. The C. armoraciae s. lat. isolates are distributed over two clades, C. armoraciae s. str. and C. bizzozeriana. The C. beticola s. lat. isolates are distributed over two clades, namely C. beticola s. str. and C. gamsiana, which is newly described

Cytotoxic, antimicrobial and antiviral secondary metabolites produced by the plant pathogenic fungus Cytospora sp. CCTU A309.

Chemical analysis of extracts from cultures of the plant pathogenic fungus Cytospora sp. strain CCTU A309 collected in Iran led to the isolation of two previously unreported heptanedioic acid derivatives namely (2R,3S) 2-hydroxy-3-phenyl-4-oxoheptanedioic acid (1) and (2S,3S) 2-hydroxy-3-phenyl-4-oxoheptanedioic acid (2) as diastereomers, four previously undescribed prenylated p-terphenyl quinones 3-6 in addition to five known metabolites. Their structures were elucidated on the basis of extensive spectroscopic analysis and high-resolution mass spectrometry. For metabolites 1 and 2, the absolute configurations at C-2 were deduced from comparison of the 1H NMR difference of their (S)- and (R)-phenylglycine methyl ester derivatives while the relative configurations were tentatively assigned by a J-based analysis and confirmed by comparison of 13C chemical shifts to literature data. The isolated compounds were tested for their cytotoxic, antimicrobial (including biofilm inhibition), antiviral, and nematicidal activities. While only moderate antimicrobial effects were observed, the terphenyl quinone derivatives 3-6 and leucomelone (10) exhibited significant cytotoxicity against the mouse fibroblast L929 and cervix carcinoma KB-3-1 cell lines with IC50 values ranging from 2.4 to 26 μg/mL. Furthermore, metabolites 4-6 showed interesting antiviral activity against hepatitis C virus (HCV)

Tetrasubstituted α-pyrone derivatives from the endophytic fungus, Neurospora udagawae

Two new -pyrone derivatives, udagawanones A (1) and B (2), along with the known compounds (Z)-4-hydroxy-3-(3-hydroxy-3-methylbut-1-en-1-yl)benzoic acid (3), isosclerone (4), cyclo-(L-Leu-L-Pro) (5), and cyclo-(L-Pro-L-Tyr) (6), were isolated from cultures of the endophyte Neurospora udagawae. Their structures were elucidated by extensive spectroscopic methods and single crystal X-ray diffraction. Both compounds feature oxidized functionalities at the C-2 position not previously observed in other tetrasubstituted -pyrones from fungi. Compound 1 exhibited moderate antibacterial (vs. Staphylococcus aureus) and antifungal (vs. Rhodoturula glutinis) activities and cytotoxicity against KB3.1 cells