Research Article |
Corresponding author: Marcin Piątek ( m.piatek@botany.pl ) Academic editor: Kevin D. Hyde
© 2024 Marcin Piątek, Monika Stryjak-Bogacka, Paweł Czachura.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Piątek M, Stryjak-Bogacka M, Czachura P (2024) Emended Neodactylariales (Dothideomycetes): Szaferohypha gen. nov. and phylogenetically related genera. MycoKeys 111: 211-228. https://doi.org/10.3897/mycokeys.111.139620
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Epiphytic fungi evolved several times in Dothideomycetes, particularly within the orders Asterinales, Capnodiales, Microthyriales, and Zeloasperisporiales, but also in other, less obvious lineages. In this study, a new genus and species, Szaferohypha and S. enigmatica, isolated from the sooty mould community on the leaves of Symphoricarpos albus in Poland, are described based on morphology and phylogenetic analysis using sequences of four DNA loci (LSU, ITS, SSU, and rpb2). Due to single isolation, it is unclear whether Szaferohypha enigmatica represents a very rare or accidental inhabitant of sooty mould communities. Szaferohypha is assigned to the poorly known family Neodactylariaceae and order Neodactylariales, together with Beaucarneamyces, Neodactylaria, and Pseudoarthrographis. The order and family were originally circumscribed based on the features of the genus Neodactylaria. Therefore, they are emended by characters of Beaucarneamyces, Pseudoarthrographis, and Szaferohypha.
Ascomycota, emended descriptions, one new genus, one new species, sooty mould communities, taxonomy
The class Dothideomycetes is megadiverse and the largest class of fungi in the phylum Ascomycota (
The high species diversity observed in Dothideomycetes is reflected by the wide geographical range and diversity of lifestyles of its members. They are known from all areas of the world and habitats, even capable of colonizing extreme habitats such as cold deserts (
Recently, we isolated an enigmatic fungus from a sooty mould colony on Symphoricarpos albus in southern Poland, which showed affinities to members of the poorly known order Neodactylariales (
The strain was isolated from the sooty mould community on Symphoricarpos albus leaves planted in municipal greenery in southern Poland (see
After growth of cultures for about one month, genomic DNA was extracted from a portion of mycelium using the DNeasy® Plant Mini Kit (Qiagen, Germany). To conduct molecular studies, four genetic loci were amplified, namely ITS1-5.8S-ITS2 rDNA (= ITS), 28S D1–D2 rDNA (= LSU), a small subunit rDNA (= SSU), and a protein-coding gene—a partial DNA-directed RNA polymerase II second largest subunit (rpb2). To amplify the loci mentioned above, four different primer pairs were used: ITS1 and LR5 for a fragment containing ITS and LSU (
The affinities of obtained ITS, LSU, SSU, and rpb2 sequences of the isolated fungus were performed in the NCBI’s GenBank nucleotide database using the megablast search tool (
The concatenated multilocus dataset (LSU, ITS, SSU, and rpb2) included sequences of 154 representatives of most of the orders of the class Dothideomycetes, including all representatives of Neodactylariales, and a member of the class Arthoniomycetes (Schismatomma decolorans) used as an outgroup. The concatenated alignment contained 4483 characters (LSU: 1082, ITS: 750, SSU: 1761, rpb2: 890, including alignment gaps). The best-fit substitution models selected for single-gene alignments were as follows: GTR+I+G4 for both ITS and LSU, TrNef+I+G4 for SSU, and TPM3uf+I+G4, TPM2uf+I+G4, and TIM2+I+G4 for rpb2 (three codons). The phylogenetic tree resulting from maximum likelihood analysis is shown in Fig.
Phylogenetic tree of selected representatives of the orders of Dothideomycetes, including all sequenced species of Neodactylariales, obtained from a maximum likelihood analysis of the combined multi-locus alignment (LSU, ITS, SSU, rpb2). The position of Szaferohypha enigmatica is indicated in bold. Numbers above branches indicate maximum likelihood bootstrap (MLB) support values > 50%. Schismatomma decolorans AFTOL-ID 307 was used as an outgroup. The scale bar represents the expected number of changes per site.
Asexual morph from human-associated organs or saprobic on plant debris or epiphytic on living leaves. Conidiophores acroauxic, macronematous or micronematous, mononematous, branched or unbranched, or reduced to conidiogenous cells. Conidiogenous cells mono- and polyblastic, sympodially extended or not. Conidia solitary or in branched or unbranched chains, hyaline or pale pigmented, smooth, verrucous, or echinulate. Chlamydospores sometimes present. Sexual morph not observed.
Neodactylaria Guevara-Suarez, Deanna A. Sutton, Wiederh. & Gené.
Because of the inclusion of genera Beaucarneamyces, Pseudoarthrographis, and Szaferohypha in Neodactylariales (
Mycelium superficial or immersed, composed of branched, septate, hyaline to subhyaline hyphae. Conidiophores macronematous or micronematous, mononematous, straight or flexuous, septate, unbranched, or reduced to conidiogenous cells. Conidiogenous cells terminal or intercalary, monoblastic or polyblastic, sympodial or not, with short-cylindrical denticles or without denticles. Conidial secession schizolytic. Conidia solitary or in branched or unbranched chains, smooth or finely echinulate. Chlamydospores sometimes present. Sexual morph not observed.
Neodactylaria Guevara-Suarez, Deanna A. Sutton, Wiederh. & Gené.
The order Neodactylariales contains one family, Neodactylariaceae, that is emended by features of genera Beaucarneamyces, Pseudoarthrographis, and Szaferohypha. The original description of this family (
Named after Polish botanist and palaeobotanist Professor Władysław Szafer (1886–1970), the first director of the W. Szafer Institute of Botany, Polish Academy of Sciences.
Colonies erumpent, spreading, umbonate, grayish-brown, with a velvety surface caused by abundant aerial mycelium, margin undulate. Mycelium composed of branched, septate, hyaline, subhyaline, pale brown, or brown, smooth or verrucose, usually thick-walled hyphae. Conidiophores micronematous, reduced to conidiogenous cells, rarely macronematous. Conidiogenous cells terminal, rarely lateral, monoblastic, hyaline, subhyaline, pale brown, or brown. Conidia globose, subglobose, rarely broadly ellipsoid, hyaline, subhyaline, or brown, aseptate, rarely with 1–2 septa or muriformly septate, smooth or finely verrucose, thick-walled, sometimes produced intercalary.
Szaferohypha enigmatica Piątek, Stryjak-Bogacka & Czachura.
Refers to the uncertain taxonomic position of this fungus after the first molecular analyses.
Poland • Małopolska Province, Tarnów County: Tarnów–Piaskówka, municipal greenery, isolated from sooty mould community on Symphoricarpos albus leaves, 1 Oct. 2018, leg. M. Piątek, W. Bartoszek & P. Czachura (holotype
Mycelium composed of branched, septate, hyaline, subhyaline, pale brown, or brown, smooth or verrucose, usually thick-walled hyphae, 2–4 µm, sometimes with oil guttules; wall ca. 0.5 µm thick. Conidiophores micronematous, reduced to conidiogenous cells, rarely macronematous. Conidiogeneous cells terminal, rarely lateral, monoblastic, hyaline, subhyaline, pale brown, or brown, 3.5–13.5 × 2.5–4.5 µm. Conidia globose, subglobose, rarely broadly ellipsoid, hyaline, subhyaline, or brown, aseptate, rarely with 1–2 septa or muriformly septate, smooth or finely verrucose, thick-walled, 6.5–15 × 6–13.5 µm, sometimes germinating into hypha or produced intercalary, wall ca. 0.5–1.5 µm thick.
Colonies on MEA erumpent, spreading, umbonate, grayish, reaching 1 mm diam. after 4 weeks at 6 °C, 4 mm diam. after 4 weeks at 15 °C, and 8 mm diam. after 4 weeks at 25 °C, with a velvety surface caused by abundant aerial mycelium, margin entire. Reverse black. Colonies on PDA erumpent, spreading, umbonate, grayish-brown, reaching 3 mm diam. after 4 weeks at 6 °C, 4 mm diam. after 4 weeks at 15 °C, and 7 mm diam. after 4 weeks at 25 °C, with a velvety surface caused by abundant aerial mycelium, margin finely undulate. Reverse black.
Colonies photographed after 15 weeks of growth, depicted in Fig.
Morphology of cultures of Szaferohypha enigmatica (strain G191 = CBS 152426) after 4 weeks of growth at 25 °C a–c general view, upper side and reverse side of colony on MEA d–f general view, upper side and reverse side of colony on PDA g general view of 15-week-old colony on MEA (to show difference in morphology) h general view of 15-week-old colony on PDA (to show difference in morphology).
Based on a megablast search of NCBI’s GenBank nucleotide database, the closest hits of the named species using the ITS sequence are Pseudoarthrographis phlogis (strain CPC 32759, GenBank MH327796; identities = 370/414 (89%), 11 gaps (2%)), Oncopodiella trigonella (strain FMR 10788, GenBank KY853455; identities = 356/408 (87%), 11 gaps (2%)), and Xylographa parallela (voucher Z. Palice 22099 (PRM), GenBank MK778618; identities = 344/396 (87%), seven gaps (1%)). The closest hits of the named species using the LSU sequence are Beaucarneamyces stellenboschensis (strain CPC 45687, GenBank PP791445; identities = 826/873 (95%), four gaps (0%)), Pseudoarthrographis phlogis (strain CPC 32759, GenBank NG_064540; identities = 835/883 (95%), no gaps), and Umbilicaria hypococcinea (strain A12, GenBank JQ739991; identities = 876/927 (94%), eight gaps (1%)). The closest hits using the SSU sequence are Cophinforma atrovirens (strain CSM_72, GenBank MF436134; identities = 857/870 (99%), no gaps), Gloeopycnis protuberans (specimen DAOM 745762, GenBank NG_067652; identities = 857/870 (99%), no gaps), and Botryosphaeria mamane (strain CBS 117444, GenBank KF531821; identities = 857/870 (99%), no gaps). The closest hits using the rpb2 sequence are Shiraia bambusicola (voucher SICAUCC 23-0005, GenBank OR424351; identities = 237/283 (84%), six gaps (2%)), Lindra obtusa (strain AFTOL-ID 5012, GenBank FJ238382; identities = 207/252 (82%), three gaps (1%)), and Natonodosa speciosa (strain CLM-RV86, GenBank MH745150; identities = 217/266 (82%), six gaps (2%)). In the case of SSU and rpb2, the sequences of these two regions are not available for representatives of the most closely related genera, namely Beaucarneamyces and Pseudoarthrographis.
Morphology of Szaferohypha enigmatica (strain G191 = CBS 152426, all on MEA) a, b subhyaline or brown, smooth or verrucose hyphae c–e subhyaline or brown intercalary conidia (figure e depicts the verrucose surface of the conidium) f hyphae and terminal conidia g–m hyaline or brown, lateral or terminal conidia emerging on conidiogenous cells (figure i depicts the verrucose surface of the conidium). Scale bars: 10 µm.
In this study, morphological and phylogenetic analyses were conducted to identify the enigmatic fungal strain isolated from sooty mould biofilm on the surface of Symphoricarpos albus leaves. In consequence, the isolated fungus is described as a new genus and species, Szaferohypha enigmatica, and assigned to the order Neodactylariales. Three genera were previously included in this order, namely Beaucarneamyces, Neodactylaria, and Pseudoarthrographis (
Beaucarneamyces, with type species B. stellenboschensis, was described from dead leaves of Beaucarnea stricta in South Africa and is characterized by hyaline conidiophores reduced to conidiogenous cells that are polyblastic with several apical denticles. Conidia in this genus are solitary, fusoid-ellipsoid, hooked, 3-septate, hyaline but with pale brown central cells (
Despite numerous strains obtained during our studies of sooty mould communities, only a single strain belonging to Szaferohypha enigmatica was isolated. It is therefore unclear whether this species represents a very rare or accidental inhabitant of these communities and its main habitat is elsewhere.
The order Neodactylariales, with one family Neodactylariaceae, was originally described to accommodate only one genus, Neodactylaria, containing two species in China and the USA (
Sooty mould communities are an underexplored source of rare and undescribed species, of which many are probably extremophilic since they live in extreme environments (
We are grateful to Wacław Bartoszek (Kraków, Poland) for help in the fieldwork.
The authors have declared that no competing interests exist.
No ethical statement was reported.
This study was funded by the National Science Centre, Poland, under the project 2017/27/B/NZ9/02902, and partly through the statutory funds of the W. Szafer Institute of Botany, Polish Academy of Sciences, Kraków.
MP: conceptualization, investigation, formal analyses, visualisation, writing—original draft preparation; MSB: investigation, formal analyses, visualisation, writing—review and editing; PC: investigation, visualisation, writing—review and editing. All authors have read and approved the final version of the manuscript.
Marcin Piątek https://orcid.org/0000-0002-4968-2861
Monika Stryjak-Bogacka https://orcid.org/0000-0003-2845-9975
Paweł Czachura https://orcid.org/0000-0002-3562-8776
The data that support the findings of this study are available in GenBank (https://www.ncbi.nlm.nih.gov/genbank/) and in culture collections and fungal herbaria, as shown in Suppl. material
List of species with strain/specimen and GenBank accession numbers used in phylogenetic analysis
Data type: docx