Biodiversity Data Journal :
Taxonomic Paper
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Corresponding author: Kevin D. Hyde (kdhyde3@gmail.com)
Academic editor: Danny Haelewaters
Received: 21 Apr 2021 | Accepted: 05 Aug 2021 | Published: 07 Sep 2021
© 2021 Vinodhini Thiyagaraja, Robert Lücking, Damien Ertz, Milan C. Samarakoon, Dhanushka N. Wanasinghe, Samantha C. Karunarathna, Ratchadawan Cheewangkoon, Kevin D. Hyde
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:
Thiyagaraja V, Lücking R, Ertz D, Samarakoon MC, Wanasinghe DN, Karunarathna SC, Cheewangkoon R, Hyde KD (2021) Mendogia diffusa sp. nov. and an updated key to the species of Mendogia (Myriangiaceae, Dothideomycetes). Biodiversity Data Journal 9: e67705. https://doi.org/10.3897/BDJ.9.e67705
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Mendogia belongs to Dothideomycetes and its members are epiphytic on living bamboo culms or palms and distributed in tropical regions. Currently, the genus comprises seven species. Another collection resembling Mendogia was collected from the leaves of Fagales sp. in Thailand. Morphological characteristics and multilocus phylogenetic analyses, using ITS, LSU and SSU sequences, showed that the fungus is new to science, described herein as Mendogia diffusa. Mendogia diffusa is characterised by apothecial ascostromata, a carbonised epithecium, dark brown setae on the ascostromatal surface, hyaline paraphysoids, ovoid to clavate asci and oblong to elliptical, muriform ascospores. The fungus has a dark pigmented surface and is occasionally facultatively associated with patches of green algae, but not actually lichenised. Instead, the fungus penetrates the upper leaf surface, forming dark pigmented isodiametric cells below the epidermis.
Re-examination of specimens of M. chiangraiensis, M. macrostroma and M. yunnanensis revealed the absence of algal associations. The status of Mendogia philippinensis (= M. calami) and M. bambusina (= Uleopeltis bambusina) was established, based on morphological comparisons and previous studies. Comprehensive morphological descriptions with phylogenetic analyses support M. diffusa as a novel species in Myriangiaceae. An updated key to the known species of the genus is also provided.
one new species, morphology, multilocus phylogeny, saprotroph, taxonomy
Dothideomycetes is the largest class in Ascomycota, comprising 19,000 species, including saprotrophs, pathogens, endophytes, epiphytes, fungicolous, lichenised and lichenicolous taxa (
Mendogia was introduced by
This study introduces a new species of Mendogia that appeared unusual due to its growth on leaves and its occasional, facultative association with patches of green algae. We conducted a detailed investigation to resolve the identity of our newly-collected material, including morphological and chemical assessments. The phylogenetic position of the taxon was investigated, based on Maximum Likelihood and Bayesian analyses of combined ITS, LSU and SSU sequences. We further re-examined herbarium collections of Mendogia chiangraiensis, M. macrostroma and M. yunnanensis to test potential associations with algae. Additionally, morphological comparisons between closely-related taxa have led to reclassify several species in Mendogia (M. philippinensis (= M. calami) and M. bambusina (= Uleopeltis bambusina)). We, therefore, provided an updated key to the genus.
The fungal material was collected in Phayao, Thailand. Herbarium specimens of Mendogia chiangraiensis, M. macrostroma and M. yunnanensis were loaned from Mae Fah Luang University Herbarium (MFLU), Chiang Rai, Thailand. Fungal structures on the substrate were observed with a stereomicroscope and micro-morphological features were examined and photographed using a Nikon Eclipse E600 fluorescence microscope with a Canon 750D digital camera. Hand sections of the ascomata were mounted in water, 5% potassium hydroxide (KOH), 5% Lugol's solution and Trypan blue. All microscopic measurements were measured in water and images were made with Tarosoft Image Frame Work (0.9.0.7) and processed with Adobe Photoshop CS6 Extended 10.0 software (Adobe Systems, San Jose, CA, USA). The newly-proposed synonymies were established, based on revision of available data from previous studies. The holotype specimen of M. diffusa was deposited in the Mae Fah Luang University (MFLU) Herbarium, Chiang Rai, Thailand.
The E.Z.N.A. Forensic DAT (D3591 – 01, Omega Bio–Tek, Guangzhou, China) kit was used to extract DNA, following the manufacturer’s instructions. DNA samples that were intended for use as a template for PCR were stored at 4°C for use in regular work; long-term storage was at -20°C. The small and large subunits (SSU, LSU) of the nuclear ribosomal RNA gene, as well as the internal transcribed spacer (ITS) region were amplified with primer pairs NS1/NS4 (
The newly-generated sequences were BLAST-searched against the NCBI GenBank standard nr/nt database (https://blast.ncbi.nlm.nih.gov/BLAST.cgi). Sequences of closely-related taxa for Myriangiales were downloaded from GenBank. We failed to generate sequences for the translation elongation factor 1-alpha (TEF1) using the primer pair EF1-983F/EF1-2218R with the PCR conditions recommended in
Taxa used in this study for the phylogenetic analyses of combined SSU, ITS and LSU sequence data and their GenBank accession numbers. The newly-generated sequences are given in black boldface.
GenBank Accessions Number | ||||
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Species | Strain | ITS | LSU | SSU |
Anhellia nectandrae | VIC 31767 | NR_111700 | NG_042604 | - |
Columnosphaeria fagi | CBS 171.93 | KT693737 | AY016359 | AY016342 |
Dothidea insculpta | CBS 189.58 | AF027764 | NG_027643 | DQ247810 |
Dothidea sambuci | DAOM 231303 | NR_111220 | NG_027611 | NG_012432 |
Dothiora cannabinae | CBS 737.71 | NR_144904 | DQ470984 | NG_062696 |
Elsinoe brasiliensis | CPC 18528 | NR_148130 | JN940394 | NG_064989 |
Elsinoe caleae | CBS 221.50 | NR_148131 | NG_064001 | - |
Elsinoe centrolobii | CBS 222.50 | NR_148132 | KX886969 | NG_062717 |
Elsinoe citricola | CPC 18535 | NR_148133 | KX886970 | JN940559 |
Elsinoe embeliae | CBS 472.62 | NR_148136 | KX886974 | - |
Elsinoe erythrinae | CPC 18542 | KX887214 | KX886977 | JN940550 |
Elsinoe eucalypticola | CBS 124765 | NR_132834 | KX886978 | - |
Elsinoe eucalyptorum | CBS 120084 | NR_155080 | KX886979 | - |
Elsinoe euphorbiae | CBS 401.63 | NR_148137 | KX886980 | - |
Elsinoe fagarae | CBS 514.50 | NR_148138 | KX886981 | - |
Elsinoe fawcettii | CBS 139.25 | NR_148139 | KX886982 | - |
Elsinoe krugii | CPC 18531 | NR_148150 | KX886998 | NG_064987 |
Elsinoe lagoa-santensis | CBS 518.50 | NR_148151 | KX887002 | - |
Elsinoe leucopogonis | CPC 32097 | NR_159836 | NG_064551 | - |
Elsinoe leucospermi | CBS 111207 | NR_148154 | KX887005 | - |
Elsinoe lippiae | CBS 166.40 | NR_148155 | NG_063985 | - |
Elsinoe mangiferae | CBS 226.50 | NR_148156 | KX887012 | - |
Elsinoe perseae | CBS 406.34 | NR_148160 | NG_063977 | - |
Elsinoe phaseoli | CBS 165.31 | NR_148161 | KX887026 | NG_062718 |
Elsinoe quercus-ilicis | CBS 232.61 | NR_148164 | - | - |
Elsinoe sesseae | CPC 18549 | KX887288 | KX887051 | JN940561 |
Elsinoe sicula | CBS 398.59 | NR_148170 | KX887052 | - |
Elsinoe solidaginis | CBS 191.37 | NR_148171 | KX887053 | - |
Elsinoe tectificae | CBS 124777 | NR_148172 | KX887055 | - |
Elsinoe terminaliae | CBS 343.39 | NR_148173 | KX887056 | - |
Elsinoe terminaliae | CPC 18538 | JN943497 | JN940371 | JN940560 |
Elsinoe theae | CBS 228.50 | NR_148174 | KX887058 | - |
Elsinoe tiliae | CBS 350.73 | KX887296 | KX887059 | - |
Elsinoe veneta | CBS 164.29 | NR_148175 | NG_059194 | NG_062714 |
Elsinoe verbenae | CPC 18561 | NR_148176 | NG_059208 | NG_064988 |
Endosporium aviarium | UAMH 10530 | NR_111286 | NG_059195 | NG_016524 |
Endosporium aviarium | UAMH 10531 | EU304352 | EU304353 | - |
Endosporium populi-tremuloidis | UAMH 10529 | EU304347 | EU304348 | EU304346 |
Mendogia diffusa | MFLU 20-0541 | MW854639 | MW854637 | MW854638 |
Mendogia chiangraiensis | MFLU 19-0005 | MK433591 | - | MK433594 |
Mendogia macrostroma | MFLU 13-0642 | NR_154192 | KU863104 | NG_065082 |
Mendogia yunnanensis | MFLU 19-0006 | - | MK433593 | MK433601 |
Myriangium citri | MAaK | KU720544 | KU720541 | - |
Myriangium citri | MAsS1 | KU720543 | KU720539 | - |
Myriangium citri | MAsS2 | KU720542 | KU720540 | - |
Myriangium duriaei | CBS 260.36 | MH855793 | NG_027579 | AY016347 |
Myriangium hispanicum | CBS 300.34 | MH855532 | MH867034 | - |
Myriangium haraeanum | CBS 247.33 | MH855426 | KX887067 | - |
Myriangium sp. | HK | KR909171 | - | - |
Sydowia polyspora | CBS 116.29 | MH 855019 | DQ678058 | DQ678005 |
Phylogenetic analyses of both individual and combined aligned data were performed under Maximum Likelihood (ML) and Bayesian Inference (BI) criteria. Multiple alignments were automatically performed for each locus with MAFFT v. 7 (http://mafft.cbrc.jp/alignment/server/index.html,
Saprotrophic on dead leaves. Thallus absent (Fig.
Mendogia diffusa (MFLU 20-0541, holotype) a–e. Vertical sections of ascomata in water (upper surface); f. Vertical section of an ascoma in water (lower surface); fh, hair-like structure on leaf; g. Ascomata in trypan blue; h, i. (a1, a2) Algae; j. Paraphysoids in water; k–m. Asci in water; n. Asci in 5% KOH stained with Lugol's solution; o1–o8. Ascospores in water. Scale bars: (a–g) = 200 μm, (h–j) = 5 μm, (k–n) = 30 μm, (g–j) = 30 μm, (o1–o8) = 10 μm
Referring to the morphology of the fungus with ascostromata that are diffuse and spread extensively on the leaves.
On dead leaves of Fagales sp. Thus far, only known from Thailand, Phayao Province, Phu Sang District.
Mendogia diffusa is the first reported species in the genus from dead dicotyledonous leaves. Other species were mostly reported from bamboo culms, with the exception of M. manaosensis that is reported from palm leaves (
Basionym: Pleiostomella philippinensis Syd. & P. Syd., Annls mycol. 15(3/4): 221 (1917); Type: The Philippines, Biliran, 1914, RC McGregor 18371 (S-F61491).
Syn. nov.: Mendogia calami H.B. Jiang, Phookamsak and K.D. Hyde, in Jiang, Phookamsak, Xu, Karunarathna, Mortimer and Hyde, Mycol. Progr. 19: 47 (2020); Type: The Philippines, Mt. Makiling, S. A. Reyes 3367a, (S-F48343).
Mendogia calami was recently introduced from leaves of Calamus sp. in the Philippines (
Syn. nov.: Uleopeltis bambusina Syd. & P. Syd., Annls mycol. 12(6): 565 (1914)
Ital. 1 (Fasc. 3): 159 (1862). Type: The Philippines, Luzon, Bulacan Prov., Angat, 1913, M Ramos, Bur. Sci. 21852 (GZU, S-F5988).
Uleopeltis was introduced to accommodate U. manaosensis and later the second species U. bambusina added to this genus (
Key to the species of Mendogia |
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1 | Ascomata scattered in dense, pseudostromatic, irregularly stellate groups over an effuse, thallus-like, dark structure, with thin covering layer, interascal hyphae forming distinct paraphysoids, asci 45–70 × 25–35 μm, ascospores 15–25 × 6–10 μm, on dead dicotyledonean leaves, Thailand | Mendogia diffusa |
– | Ascomata one to many immersed in sharply delimited, rounded ascostromata, without associated thallus-like structure, interascal hyphae, asci and ascospores variable, on living bamboo culms or palm leaves | 2 |
2 | Ascospores narrowly oblong, transversely septate, 30–55 × 3.5–4.5 μm, interascal hyphae forming sparsely branched paraphysoids, asci cylindrical-clavate, 85–120 × 10–12 μm, Brazil | Mendogia manaosensis (≡ Uleopeltis manaosensis) |
– | Ascospores broadly oblong to somewhat tapering, muriform, interascal hyphae variable, asci broadly oblong to obclavate | 3 |
3 | Ascostromata with distinct chambers appearing peritheciiform in cross section, but forming dense, concentric structures, with the asci in a single layer formed at the bottom of the chambers (type II), interascal hyphae forming more or less distinct paraphysoids, asci 45–55 × 16–20 μm, ascospores 14–18 × 5–6.5 μm, on living palm leaves, Philippines | Mendogia philippinensis (≡ Pleiostomella philippinensis) (≡ Mendogia calami) |
– | Ascostromata indistinctly chambered (arthothelioid) or asci in concentric structures mostly towards the periphery, with the asci irregularly dispersed in irregular layers (type I), on bamboo culms (rarely on palm leaves) interascal hyphae forming indistinct paraphysoids or textura angulate | 4 |
4 | Interascal hyphae forming indistinct paraphysoids, asci developing in concentric structures mostly towards the periphery, 17–25 μm broad, ascospores 15–28 × 7–11 μm, without gelatinous caps, on bamboo culms or palm leaves, USA, Brazil, Indonesia, Philippines | Mendogia bambusina (≡ Uleopeltis bambusina) |
– | Interascal hyphae forming a textura angulata, asci and ascospores variable | 5 |
5 | Ascostromata 5–20 mm diam., asci 70–85 × 28–35 μm, ascospores 20–27 × 9–11 μm, without gelatinous sheath or caps, on bamboo culms, Thailand | Mendogia macrostroma |
– | Ascostromata 1–5 mm diam., asci and ascospores variable in size, but ascospores with thin gelatinous sheath and distinct gelatinous caps | 6 |
6 | Asci 55–75 × 25–30 μm, ascospores 19–23 × 8–11 μm, on bamboo culms, China | Mendogia yunnanensis |
– | Asci 75–165 × 30–40 μm, ascospores 25–35 × 12–16 μm, on bamboo culms, Thailand | Mendogia chiangraiensis |
The genera of Myriangiaceae were well recovered, as studied in
Mendogia has previously been recorded from monocotyledons, but, in the present case, was collected on a dicotyledon, indicating many more species are likely to be discovered. Other species currently recognised in Mendogia (see key above) differ from the new species in the sharply delimited ascostroma (
Phylogeny of Myrangiales reconstructed from a multilocus dataset with SSU, LSU, ITS1, 5.8S and ITS2. The topology is the result of ML inference performed with IQ-TREE. ML bootstrap support values ≥ 65% and Bayesian posterior probabilities ≥ 0.95 are presented above each branch. Ex-type strains are shown in black bold; the new species is highlighted in blue bold font.
Mendogia diffusa was found on dead leaves and the fungal structures penetrate the upper epidermis of the leaf surface, turning the epidermal cells into a dark pigmented layer (Fig.
We thank the Thailand Research Fund (“The future of specialist fungi in a changing climate: baseline data for generalist and specialist fungi associated with ants, Rhododendron species and Dracaena species DBG6080013” and “Impact of climate change on fungal diversity and biogeography in the Greater Mekong Sub-region RDG6130001”) and “The 2019 high-end foreign expert introduction plan to Kunming Institute of Botany (granted by the Ministry of Science and Technology of the People’s Republic of China (Grant Number G20190139006)) for funding this research. Kevin D. Hyde thanks Chiang Mai University for the award of Visiting Professor. S.C. Karunarathna would like to thank the CAS President’s International Fellowship Initiative (PIFI) young staff under grant number: 2020FYC0002 and the National Science Foundation of China (NSFC) under the project code 31851110759, the CAS President’s International Fellowship Initiative (PIFI) under the following grant: 2018PC0006 and the National Science Foundation of China (NSFC, project code 31851110759). We also thank Udeni Jayalal, Nalin Wijayawardene, Diana Sandamali and Danushka Sandaruwan for their support during this research. We thank Shaun Pennycook, for helping in the nomenclature. Dhanushka Wanasinghe would like to thank CAS President’s International Fellowship Initiative (PIFI) for funding his postdoctoral research (number 2021PC0008), the National Science Foundation of China and the Chinese Academy of Sciences for financial support under the following grants: 41761144055, 41771063 and Y4ZK111B01.