Research Article |
Corresponding author: Ji-Chuan Kang ( jckang@gzu.edu.cn ) Academic editor: Andrew Miller
© 2022 Lakmali S. Dissanayake, Diana S. Marasinghe, Milan C. Samarakoon, Sajeewa S.N. Maharachchikumbura, Peter E. Mortimer, Kevin D. Hyde, Chang-Hsin Kuo, Ji-Chuan Kang.
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Citation:
Dissanayake LS, Marasinghe DS, Samarakoon MC, Maharachchikumbura SS, Mortimer PE, Hyde KD, Kuo C-H, Kang J-C (2022) Three new species of Iodosphaeria (Xylariomycetidae): I. chiayiensis, I. jinghongensis and I. thailandica. MycoKeys 86: 1-17. https://doi.org/10.3897/mycokeys.86.75801
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Three fungal specimens (two sexual and one asexual) were collected during fieldwork conducted in China, Taiwan and Thailand. Both sexual morphs share superficial, black ascomata surrounded by flexuous setae; 8-spored, unitunicate, cylindrical asci, with J+, apical ring, and ellipsoidal to allantoid, aseptate, guttulate ascospores. The asexual morph has ceratosporium-like conidia arising from aerial hyphae with a single arm and are usually attached or with 2–3 arms, brown, often with a subglobose to conical cell at the point of attachment. Morphological examinations and phylogenetic analyses of a combined LSU-ITS dataset via maximum likelihood and Bayesian analyses indicated that these three collections were new species. Iodosphaeria chiayiensis (sexual morph), I. thailandica (sexual morph) and I. jinghongensis (asexual morph) are therefore introduced as new species in this study. Iodosphaeria chiayiensis has small, hyaline and ellipsoidal to allantoid ascospores, while I. thailandica has large ascomata, cylindrical to allantoid asci and hyaline to pale brown ascospores.
Ceratosporium-like asexual morph, Sordariomycetes, taxonomy, three new taxa
Iodosphaeria was introduced by
This study introduces three novel Iodosphaeria species from China, Taiwan, and Thailand. Detailed morphological descriptions, illustrations and a key are provided, and phylogenetic affinities of the new taxa are discussed.
Dead leaves were collected from Dahu Forest (Chiayi City, Taiwan) during autumn (September 2019), from dead twigs in Jinghong City (Yunnan Province, China) during winter (December 2019) and from dead leaves at MRC (Mushroom Research Centre, Chiang Mai, Thailand) during the rainy season (September 2020). Specimens were treated following the methods outlined in
DNA extraction, PCR amplification and sequencing were carried out following the methods described in
Newly generated sequences were assembled and subjected to the standard BLAST search to identify the closest matches in GenBank. The accession numbers of taxa used in our analyses are shown in Table
Taxa used in the phylogenetic analyses and corresponding GenBank accession numbers.
Taxon | Specimen/Strain | GenBank accession numbers | References | |
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ITS | LSU | |||
Delonicicola siamense | MFLUCC 15-0670 T | MF167586 | MF158345 |
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Furfurella luteostiolata | CBS 143620 T | MK527842 | MK527842 | Voglmayr et al. (2019) |
Iodosphaeria chiayiensis | MFLU 21-0042 T | MZ918994 | MZ918992 | This study |
I. foliicola | NBM-F-07096 T | MZ509148 | MZ509160 |
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I. honghensis | MFLU 19-0719 T | MK737501 | MK722172 | Marasinghe et al. (2019) |
I. jinghongensis |
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MZ918989 | MZ923776 | This study |
I. phyllophila | PDD 56626 | MZ509149 | MZ509149 |
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I. phyllophila | FC 5099-2d | MZ509150 | N/A |
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I. phyllophila | ILLS00121493 T | MZ509151 | N/A |
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I. ripogoni | PDD 103350 | MZ509152 | MZ509152 |
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I. thailandica | MFLU 21-0041 T | MZ923759 | MZ923758 | This study |
I. tongrenensis | MFLU 15-0393 T | KR095282 | KR095283 |
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Oxydothis metroxylonicola | MFLUCC 15-0281 T | KY206776 | KY206765 |
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O. palmicola | MFLUCC 15-0806 T | KY206774 | KY206763 |
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O. phoenicis | MFLUCC 18-0270 T | MK088066 | MK088062 |
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Pseudosporidesmium knawiae | CBS 123529 T | FJ349609 | FJ349610 |
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P. lambertiae | CBS 143169 T | MG386034 | MG386087 |
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Vialaea insculpta | DAOM 240257 | KC181926 | KC181924 |
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V. mangiferae | MFLUCC 12-0808 T | KF724974 | KF724975 |
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V. minutella | BRIP 56959 | JX139726 | JX139726 |
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The combined LSU and ITS comprise 20 taxa including the outgroup taxa. The best scoring RAxML tree is shown in Figure with a final ML optimization likelihood value of -7278.703992. The matrix had 575 distinct alignment patterns, with 19.44% undetermined characters or gaps. Estimated base frequencies were: A = 0.245534, C = 0.244177, G = 0.286855, T = 0.223434 substitution rates AC = 1.190714, AG = 2.269637, AT = 1.889784, CG = 1.069908, CT = 5.997198, GT = 1.000000; proportion of invariable sites I = 0.39717; gamma distribution shape parameters α = 0.578305. Both trees (ML and BYPP) were similar in topology and did not differ in species relationships, which is in agreement with multi-gene phylogenies of previous studies (Marasinghe et al. 2019;
In the combined multi-gene phylogenetic analysis, Iodosphaeriaceae received 100% ML and 1.00 BYPP support values (Figure
The specific epithet chiayiensis refers to the city name where the fungus was collected.
Saprobic on dead leaves of an unidentified host. Sexual morph: Ascomata 150–190 × 160–200 μm (x̅ = 170 × 180 μm, n = 10), globose to subglobose, superficial, black, solitary to gregarious, consisting of numerous long, flexuous setae. Setae 3–5 μm wide, arising from cells at the peridium surface, brown, unbranched, septate, apex flattened. Ostiole periphysate, apapillate. Peridium 50–55 μm wide (x̅ = 53.4 μm, n = 10), comprises two layers of textura angularis cells, outer layer of dark brown to black thick-walled cells, and an inner layer of flattened, light brown. Paraphyses 2–4 μm wide, shorter than asci, hyaline, embedded in a gelatinous matrix. Asci 60–90 × 8–10 μm (x̅ = 72.9 × 9.2 μm, n = 30), 8-spored, unitunicate, cylindrical, shortly pedicellate, apex rounded, with a J+ apical ring. Ascospores 15–20 × 4–6 μm (x̅ = 17.2 × 5.2 μm, n = 30), overlapping uni-seriate, ellipsoidal to allantoid, aseptate, hyaline, guttulate. Asexual morph: Undetermined
Iodosphaeria chiayiensis (
Taiwan, Chiayi, Fanlu Township area, on dead leaves of an undetermined species, 10 September 2019, D.S Marasinghe, DTF018 (
Iodosphaeria chiayiensis resembles I. polygoni which has globose to sub globose, superficial, solitary to gregarious ascomata, cylindrical, short pedicellate asci with J+, apical rings and ellipsoidal to allantoid, aseptate, guttulate ascospores. However, I. chiayiensis differs from I. polygoni in having smaller ascomata (150–190 × 160–200 μm vs. 270–475 × 250–500 μm) and shorter asci (60–90 × 8–10 μm vs. 150–180 × 10–13 μm) (
The specific epithet jinghongensis refers to the city name where the fungus was collected.
Saprobic on dead twigs of an unidentified host. Sexual morph: Undetermined. Asexual morph: Colonies on natural substrate effuse, punctiform, scattered, blackish brown, mycelium mostly superficial, non-branched, hyaline, smooth hyphae. Conidiophores micronematous, smooth, flexuous, pale brown. Conidia ceratosporium-like, arising from aerial hyphae, solitary, dry, composed of a central cell and 2–3 arms. Arms 70–93 × 9–14 μm (x̅ = 79.8 × 12.1 μm, n = 20), wide at the tip 5–8 μm (x̅ = 6.9 μm), radiating from the centrally located attachment point, multi-septate (9–10), each septum with a central pore, brown, often with a sub-globose to conical cell at the point of attachment, dehiscence scar circular 3–4 μm diam. (x̅ = 3.5 μm).
China, Yunnan Province, Xishuangbanna Dai Autonomous Prefecture, Jinghong City, Jinghaxiang (21°780617'N, 101°056122'E), on a dead twig of undetermined species, 19 December 2019, D.N. Wanasinghe, DW060 (
Iodosphaeria jinghongensis is similar to I. ripogoni in having septate, brown, subglobose to conical conidia with 2–3 arms (Figure
The specific epithet thailandica refers to the country where the fungus was collected.
Saprobic on dead leaves of unidentified host. Sexual morph: Ascomata 250–285 × 250–295 μm (x̅ = 267.3 × 272 μm, n = 10), globose to subglobose, superficial, black, solitary to gregarious, consisting of numerous long, flexuous setae. Setae 4.5 μm wide, arising from cells at the peridium surface, dark brown to brown, unbranched, septate. Ostiole periphysate, apapillate. Peridium 40–50 μm wide (x̅ = 44.6 μm, n = 10), comprising two layers of cells of textura angularis, outer layer of dark brown to black thick-walled cells and an inner layer of flattened, hyaline cells. Paraphyses 5–8 μm wide, length as longer than asci, septate, hyaline, branched, embedded in a gelatinous matrix. Asci 65–100 × 8–10 μm (x̅ = 84.3 × 8.9 μm, n = 30), 8-spored, unitunicate, cylindrical, short pedicellate, apex rounded, with a J+ apical ring. Ascospores 20–35 × 2–4 μm (x̅ = 29.1 × 3.2 μm, n = 30), overlapping uni-seriate, cylindrical to allantoid, aseptate, hyaline to pale brown, guttulate, slightly curved. Asexual morph: Undetermined.
Iodosphaeria thailandica (
Thailand, Chiang Mai, Mushroom Research Centre, on dead leaves of an undetermined species, 11 September 2020, D.S Marasinghe, DMRC011 (
Iodosphaeria thailandica shares similar characteristics with I. honghensis in having globose to subglobose, superficial, solitary to gregarious ascomata, cylindrical, short pedicellate, J+, apical ring and cylindrical to allantoid asci with aseptate, guttulate ascospores (Marasinghe et al. 2019). However, I. thailandica differs from I. honghensis in having long, narrow (20–35 × 2–4 μm) and hyaline to pale brown ascospores versus short, broad (18.5–22.5 × 4.5–6.5 μm) and hyaline ascospores. In the phylogenetic analyses, I. thailandica is distinct from other species in the genus by 100 % ML and 1.00BYPP and sister to the I. chiayiensis. Iodosphaeria thailandica has larger ascomata (250–285 × 250–295 μm), cylindrical to allantoid asci and hyaline to pale brown ascospores, while the ascomata of I. chiayiensis are smaller (150–190 × 160–200 μm) and ascospores are hyaline and ellipsoidal to allantoid. Iodosphaeria thailandica is the first report of Iodosphaeria from Thailand.
1 | Asci with a distinct apical ring | 2 |
– | Asci lacking a distinct apical ring | 10 |
2 | Apical ring not staining blue in Melzer’s reagent | I. arundinariae |
– | Apical ring staining blue in Melzer’s reagent | 3 |
3 | Ascomata immersed to erumpent | I. aquatica |
– | Ascomata superficial | 4 |
4 | Ascospores guttulate | 5 |
– | Ascospores eguttulate | 8 |
5 | Ascospores ellipsoidal | 6 |
– | Ascospores cylindrical | 7 |
6 | Ascomata 270–475 × 250–500 μm | I. polygoni |
– | Ascomata 150–190 × 160–200 μm | I. chiayiensis |
7 | Ascospores 18.5–22.5 × 4.5–6.5 μm, hyaline | I. honghensis |
– | Ascospores 20–35 × 2–4 μm, hyaline to pale brown | I. thailandica |
8 | Asci shorter than 150 μm | 9 |
– | Asci longer than 150 μm | I. tongrenensis |
9 | Ascospores allantoid | 11 |
– | Ascospores ellipsoidal | I. podocarpi |
10 | Ascospores with a mucilaginous sheath | I. ripogoni |
– | Ascospores without a mucilaginous sheath | I. hongkongensis |
11 | Paraphyses of similar length to asci | I. foliicola |
– | Paraphyses longer than asci | I. phyllophila |
Iodosphaeria is seldom collected. In 15 years of studying fungi in Hong Kong, only a single collection was found despite intensive collection efforts (
The asexual morphs of this genus were recorded as selenosporella- or ceratosporium-like (
Ji-Chuan Kang thanks the National Natural Science Foundation of China (NSFC Grants Nos. 31670027 & 31460011) and the Open Fund Program of Engineering Research Center of Southwest Bio-Pharmaceutical Resources, Ministry of Education, Guizhou University (No. GZUKEY 20160705). Shaun Pennycook is thanked for the nomenclatural advice. Dhanushka Wanasinghe is thanked for the specimen collections and for providing sequence data. Peter Mortimer thanks the National Science Foundation of China (grant no. 41761144055) and High-End Foreign Experts” in the High-Level Talent Recruitment Plan of Yunnan Province (2021). Austin G. Smith at World Agroforestry (ICRAF), Kunming Institute of Botany, China, is thanked for English editing.