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An undescribed Colletotrichum species was isolated from leaf spots on Rubus idaeus (raspberry) in the summer of 2013 in the Jilin Province in northeast China. Based on morphology and ITS sequence data, it was identified as belonging to the Colletotrichum destructivum species complex. Phylogenetic analyses of combined ITS, GAPDH, ACT, CHS-1 and TUB2 sequence data revealed that the fungus represents a new species described here as Colletotrichum neorubicola sp. nov. Pathogenicity testing confirmed that this new species is pathogenic to R. idaeus.

Background Previous phylogenetic analyses of species within the genus Golovinomyces (Ascomycota, Erysiphales), based on ITS and 28S rDNA sequence data, revealed a co-evolutionary relationship between powdery mildew species and hosts of certain tribes of the plant family Asteraceae. Golovinomyces growing on host plants belonging to the Heliantheae formed a single lineage, comprised of a morphologically differentiated complex of species, which included G. ambrosiae, G. circumfusus, and G. spadiceus. However, the lineage also encompassed sequences retrieved from Golovinomyces specimens on other Asteraceae tribes as well as other plant families, suggesting the involvement of a plurivorous species. A multilocus phylogenetic examination of this complex, using ITS, 28S, IGS (intergenic spacer), TUB2 (beta-tubulin), and CHS1 (chitin synthase I) sequence data was carried out to clarify the discrepancies between ITS and 28S rDNA sequence data and morphological differences. Furthermore, the circumscription of species and their host ranges were emended. Results The phylogenetic and morphological analyses conducted in this study revealed three distinct species named, viz., (1) G. ambrosiae emend. (including G. spadiceus), a plurivorous species that occurs on a multitude of hosts including, Ambrosia spp., multiple species of the Heliantheae and plant species of other tribes of Asteraceae including the Asian species of Eupatorium; (2) G. latisporus comb. nov. (≡ Oidium latisporum), the closely related, but morphologically distinct species confined to hosts of the Heliantheae genera Helianthus, Zinnia, and most likely Rudbeckia; and (3) G. circumfusus confined to Eupatorium cannabinum in Europe. Conclusions The present results provide strong evidence that the combination of multi-locus phylogeny and morphological analysis is an effective way to identify species in the genus Golovinomyces.

Recently published phylogenetic analyses of the Golovinomyces orontii complex revealed that three different species of the genus Golovinomyces may occur on cucurbitaceous hosts, viz., G. bolayi, G. orontii s. str., and G. tabaci. Owing to its morphological characteristics, Erysiphe cucurbitacearum (≡ G. cucurbitacearum) was tentatively reduced to synonym with G. tabaci. However, final conclusions on the identity and status of E. cucurbitacearum, described from China on Cucumis sativus, as putative synonym of G. tabaci required a phylogenetic confirmation and epitypification with ex-epitype sequences. Therefore, a sample of G. cucurbitacearum collected on C. sativus in Xinjiang Uygur Autonomous Region, China, in 2014 (HMJAU-PM91862) has been sequenced and is designated as epitype of the latter species, since its holotype material (HMAS 40016, collected in 1954) turned out to be too old for molecular examinations. As a result of morphological examinations and phylogenetic analyses based on ex-epitype ITS and 28S rDNA sequences, the recently assumed synonymy of G. cucurbitacearum, found on C. sativus in China, with G. tabaci could be confirmed. In addition, two new host species of G. tabaci, viz., Trigonotis peduncularis (Boraginaceae) and Rubia cordifolia (Rubiaceae), were concurrently identified. Trigonotis peduncularis is the first verified boraginaceous host for G. tabaci.

In August 2014, leaf spots were found on Polygonatum odoratum in Jilin Province in China. The fungus isolated from the diseased leaves was identified as Colletotrichum spaethianum based on pathogenicity, morphology and molecular characterization. The fungus was re-isolated from lesions that developed on leaves after inoculation. This report is the first of a disease on P. odoratum caused by C. spaethianum.

Erysiphe longissima is a species of Erysiphe sect. Microsphaera endemic to China. Its asexual morph is poorly known and DNA sequence data are unrecorded since its first description in 1977. In 2016 and 2017, two powdery mildew samples with asexual and sexual morphs were collected on Caragana rosea at Jilin Agricultural University, Jilin Province, China. The morphological observations suggested that the two samples belonged to E. longissima. To study the phylogenetic position of E. longissima, a phylogenetic tree was constructed based on the combined ITS and 28S rDNA sequence data. This fungus was close to E. palczewskii in phylogeny and clearly distinguished from other species of Erysiphe sect. Microsphaera. To our knowledge, this is the first detailed record of the asexual morph and molecular data of E. longissima.

This is the twelfth contribution to the Fungal Diversity Notes series on fungal taxonomy, based on materials collected from many countries which were examined and described using the methods of morphology, anatomy, and strain culture, combined with DNA sequence analyses. 110 taxa are described and illustrated, including five new genera, 92 new species, eight new combinations and other taxonomic contributions (one new sequenced species, one new host and three new records) which are accommodated in 40 families and 1 incertae sedis in Dothideomycetes. The new genera are Amyloceraceomyces, Catenuliconidia, Hansenopezia, Ionopezia and Magnopulchromyces. The new species are Amyloceraceomyces angustisporus, Amylocorticium ellipsosporum, Arthrinium sorghi, Catenuliconidia uniseptata, Clavulina sphaeropedunculata, Colletotrichum parthenocissicola, Coniothyrium triseptatum, Cortinarius indorusseus, C. paurigarhwalensis, C. sinensis, C. subsanguineus, C. xiaojinensis, Diaporthe pimpinellae, Dictyosporella guizhouensis, Diplodia torilicola, Fuscoporia marquesiana, F. semiarida, Hansenopezia decora, Helicoarctatus thailandicus, Hirsutella hongheensis, Humidicutis brunneovinacea, Lentaria gossypina, L. variabilis, Lycoperdon lahorense, L. pseudocurtisii, Magnopulchromyces scorpiophorus, Moelleriella gracilispora, Neodevriesia manglicola, Neodidymelliopsis salvia, N. urticae, Neoroussoella magnoliae, Neottiella gigaspora, Ophiosphaerella chiangraiensis, Phaeotremella yunnanensis, Podosphaera yulii, Rigidoporus juniperinus, Rhodofomitopsis pseudofeei, Russula benghalensis, Scleroramularia vermispora, Scytinopogon minisporus, Sporormurispora paulsenii, Thaxteriellopsis obliqus, Tomentella asiae- orientalis, T. atrobadia, T. atrocastanea, T. aureomarginata, T. brevis, T. brunneoflava, T. brunneogrisea, T. capitatocystidiata, T. changbaiensis, T. citrinocystidiata, T. coffeae, T. conclusa, T. cystidiata, T. dimidiata, T. duplexa, T. efibulata, T. efibulis, T. farinosa, T. flavidobadia, T. fuscocrustosa, T. fuscofarinosa, T. fuscogranulosa, T. fuscopelliculosa, T. globospora, T. gloeocystidiata, T. griseocastanea, T. griseofusca, T. griseomarginata, T. inconspicua, T. incrustata, T. interrupta, T. liaoningensis, T. longiaculeifera, T. longiechinuli, T. megaspora, T. olivacea, T. olivaceobrunnea, T. pallidobrunnea, T. pallidomarginata, T. parvispora, T. pertenuis, T. qingyuanensis, T. segregata, T. separata, T. stipitata, T. storea, Trichoderma ceratophylletum, Tyromyces minutulus, Umbelopsis heterosporus and Xylolentia reniformis. The new combinations are Antrodiella descendena, Chloridium macrocladum, Hansenopezia retrocurvata, Rhodofomitopsis monomitica, Rh. oleracea, Fuscoporia licnoides, F. scruposa and Ionopezia gerardii. A new sequenced species (Graphis supracola), one new host (Aplosporella prunicola) and three new geographical records (Golovinomyces monardae, Paradictyoarthrinium diffractum and Prosthemium betulinum), are reported.

Additional file 1: Figure S1. Phylogenetic analysis of the ITS region of the Golovinomyces ambrosiae complex and G. circumfusus. The tree was constructed based on 73 sequences from tribe Golovinomyceteae. One sequence from Erysiphe kenjiana (accession number: MK452611) was used as an outgroup. Bootstrap values based on 1000 replications are indicated above the branches.

Additional file 4: Figure S4. Phylogenetic analysis of Golovinomyces ambrosiae complex and G. circumfusus based on the TUB2 region. The tree was constructed based on 43 sequences from tribe Golovinomyceteae and one sequence from Erysiphe kenjiana (accession number: MK452458) was used as an outgroup. Bootstrap values based on 1000 replications are indicated above/below the branches.

Additional file 5: Figure S5. Phylogenetic analysis of the CHS1 region of the Golovinomyces ambrosiae complex and G. circumfusus. The tree was constructed based on 49 sequences from tribe Golovinomyceteae. Three sequences from Neoërysiphe galeopisidis (accession numbers: MK452438, MK452439, MK452440) was used as an outgroup. Bootstrap values based on 1000 replications are indicated above/below the branches.

Additional file 2: Figure S2. Phylogenetic analysis of the 28S rDNA region of the Golovinomyces ambrosiae complex and G. circumfusus. The tree was constructed based on 74 sequences from tribe Golovinomyceteae. One sequence from Erysiphe kenjiana (accession number: MK452684) was used as an outgroup. Bootstrap values based on 1000 replications are indicated above the branches.

Lettuce (Lactuca sativa L. var. ramosa Hort.) is one of the most popular leafy vegetables in China, which contains abundant vitamin C and moderate iron. In August and October 2017, two different lettuce cultivars, heading type with green leaves (iceberg lettuce) and looseleaf type with red leaves, infected by powdery mildews were collected in Jilin Agricultural University (43.81°N; 125.41°E), Changchun, China. The disease incidence was approximately 60–70%. This disease initially formed small, amphigenous and indistinct white colonies, finally covering whole leaf surfaces, which caused leaf yellowing and withering and severely influences on yield and quality. Conidia were formed in short chains (catenescent) without fibrosin bodies. Chasmothecia were not observed on the collected samples. Based on the morphological characteristics of the fungus on lettuces, internal transcribed spacer (ITS) and 28S rDNA sequences and pathogenicity, the pathogen was identified as Golovinomyces orontii. It is the first report of G. orontii infections on lettuce in China. The information may be helpful for disease monitoring to lettuce growers and breeders.

Podosphaera paracurvispora, a new powdery mildew species of Podosphaera sect. Podosphaera, is described and illustrated on Pyrus ussuriensis in China. Podosphaera paracurvispora differs from P. clandestina and P. leucotricha which are common causal agents of Pyrus powdery mildew in having crescent-shaped ascospores, and from P. curvispora, endemic in Japan on Sorbus spp., in having much broader pale brown ascospores. The morphological characteristics and phylogenetic analyses strongly suggest that the fungus is a new, undescribed species.