Research Article |
Corresponding author: Sheng-Hua Wu ( shwu@mail.nmns.edu.tw ) Academic editor: R. Henrik Nilsson
© 2019 Sheng-Hua Wu, Chia-Ling Wei, Yu-Ting Lin, Chiung-Chih Chang, Shuang-Hui He.
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:
Wu S-H, Wei C-L, Lin Y-T, Chang C-C, He S-H (2019) Four new East Asian species of Aleurodiscus with echinulate basidiospores. MycoKeys 52: 71-87. https://doi.org/10.3897/mycokeys.52.34066
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Four new species of Aleurodiscus sensu lato with echinulate basidiospores are described from East Asia: A. alpinus, A. pinicola, A. senticosus, and A. sichuanensis. Aleurodiscus alpinus is from northwest Yunnan of China where it occurs on Rhododendron in montane habitats. Aleurodiscus pinicola occurs on Pinus in montane settings in Taiwan and northwest Yunnan. Aleurodiscus senticosus is from subtropical Taiwan, where it occurs on angiosperms. Aleurodiscus sichuanensis is reported from southwest China on angiosperms in montane environments. Phylogenetic relationships of these four new species were inferred from analyses of a combined dataset consisting of three genetic markers, viz. 28S, nuc rDNA ITS1-5.8S-ITS2 (ITS), and a portion of the translation elongation factor 1-alpha gene, TEF1.
China, corticioid fungi, Taiwan, taxonomy, wood-decaying fungi
The genus Aleurodiscus Rabenh. ex J. Schröt. belongs to the Stereaceae Pilát of the Russulales Kreisel ex P.M. Kirk, P.F. Cannon & J.C. David. However, whether to keep Aleurodiscus in a broad or a narrow sense has long been a puzzling issue in the taxonomy of Basidiomycota (
During a two-decade long, ongoing survey of corticioid fungi from mainland China and Taiwan, we have found four new species of Aleurodiscus with echinulate basidiospores based on morphological characters. In addition, phylogenetic analyses of a nuclear rDNA 28S D1–D2 domains (28S) dataset and analyses of a second dataset consisting of three genetic markers – nuc rDNA 28S D1–D2 domains (28S), nuc rDNA ITS1-5.8S-ITS2 (ITS), and translation elongation factor 1-alpha (TEF1) – are performed to complement our morphological observations and place the newly described species in a molecular phylogenetic framework.
Macroscopic and microscopic studies were based on dried specimens. Color names from
Dried specimens or the mycelial colonies cultured on MEA were used for DNA extraction, carried out with a Plant Genomic DNA Extraction Miniprep System (Viogene-Biotek Corp., New Taipei City, Taiwan). Liquid N and Tissue Lyser II (Qiagen, Hilden, Germany) were used to disrupt and homogenize the fungal tissues before DNA extraction process. The primer pairs ITS1/ITS4 or ITS1F/LR22 were used for the ITS region (
The newly generated sequences were added to the DNA sequence dataset employed by
List of species, specimens and sequences used in this study. Sequences generated in this study are shown in boldface.
Fungal species | Specimen or strain no. | DDBJ/GenBank/EMBL accession no. | ||
---|---|---|---|---|
ITS | 28S | TEF1 | ||
Acanthobasidium bambusicola | He2357 | KU559343 | KU574833 | – |
Acanthofungus rimosus# | Wu9601-1 | MF043521 | AY039333 | – |
Acanthophysellum cerussatum | He20120920-3 | KU559339 | KU574830 | KU992716 |
Aleurobotrys botryosus# | He2712 | KX306877 | KY450788 | – |
Aleurocystidiellum disciforme | He3159 | KU559340 | KU574831 | KU992721 |
Aleurocystidiellum subcruentatum# | He2886 | KU559341 | KU574847 | KU992720 |
Aleurodiscus alpinus | Wu1407-59 | MF043522 | MF043527 | – |
Aleurodiscus alpinus | Wu1407-55* | – | MF043526 | LC269190 |
Aleurodiscus alpinus | Wu1407-61 | MF043523 | MF043528 | – |
Aleurodiscus amorphus# | Ghobad-Nejhad-2464 | KU559342 | KU574832 | KU992717 |
Aleurodiscus amorphus# | KHL4240 | AF506397 | AF506397 | – |
Aleurodiscus bambusinus | He 4261 | KY706207 | KY706219 | LC430911 |
Aleurodiscus canadensis | Wu 1207-90 | KY706203 | KY706225 | – |
Aleurodiscus dextrinoideocerussatus | EL25-97 | AF506401 | AF506401 | – |
Aleurodiscus dextrinoideophyses | He 4105 | MH109050 | KY450784 | – |
Aleurodiscus effusus | He2261 | KU559344 | KU574834 | KU992719 |
Aleurodiscus gigasporus | Wu 0108-15 | KY706205 | KY706213 | – |
Aleurodiscus grantii | HHB-14417 | KU559363 | KU574821 | KU992708 |
Aleurodiscus grantii | HHB-14418 | KU559364 | KU574822 | – |
Aleurodiscus isabellinus | He 5283 | MH109052 | MH109046 | LC430912 |
Aleurodiscus mesaverdense | FP-120155 | KU559359 | KU574817 | – |
Aleurodiscus mirabilis | Dai13281 | KU559350 | KU574839 | KU992711 |
Aleurodiscus oakesii | He2243 | KU559352 | KU574840 | – |
Aleurodiscus oakesii | HHB11890-A-sp | KU559365 | KU574823 | – |
Aleurodiscus pinicola | Wu1106-16 | MF043524 | MF043529 | – |
Aleurodiscus pinicola | Wu1308-54* | MF043525 | MF043530 | LC269191 |
Aleurodiscus senticosus | Wu1209-7* | MH596849 | MF043531 | LC271169 |
Aleurodiscus senticosus | Wu1209-9 | MH596850 | MF043533 | LC269192 |
Aleurodiscus senticosus | Wu9610-1 | MH596851 | MF043532 | LC269193 |
Aleurodiscus sichuanensis | Wu0010-18* | MH596852 | MF043534 | LC269194 |
Aleurodiscus sichuanensis | He 4935 | LC430904 | LC430907 | – |
Aleurodiscus subroseus | He 4807 | MH109054 | MH109048 | – |
Aleurodiscus subroseus | He 4895 | LC430903 | LC430910 | LC430913 |
Aleurodiscus tenuissimus | He3575 | KX306880 | KX842529 | – |
Aleurodiscus thailandicus | He 4099 | KY450781 | KY450782 | – |
Aleurodiscus tropicus | He3830 | KX553875 | KX578720 | LC269195 |
Aleurodiscus verrucosporus | He 4491 | KY450786 | KY450790 | – |
Aleurodiscus wakefieldiae | He2580 | KU559353 | KU574841 | KU992710 |
Boidinia macrospora | Wu9202-21 | AF506377 | AF506377 | – |
Conferticium heimii | CBS321.66 | AF506381 | AF506381 | – |
Conferticium ravum | NH13291 | AF506382 | AF506382 | – |
Gloeocystidiellum aspellum | LIN625 | AF506432 | AF506432 | – |
Gloeocystidiellum porosum # | Wu 1608-176 | LC430905 | LC430908 | – |
Gloeocystidiopsis cryptacanthus | KHL10334 | AF506442 | AF506442 | – |
Gloeocystidiopsis flammea# | CBS324.66 | AF506437 | AF506437 | – |
Heterobasidion parviporum | 91605 | KJ651503 | KJ651561 | KU985089 |
Megalocystidium chelidonium | LodgeSJ110.1 | AF506441 | AF506441 | – |
Megalocystidium leucoxanthum# | HK9808 | AF506420 | AF506420 | – |
Megalocystidium wakullum | Oslo-930107 | AF506443 | AF506443 | – |
Neoaleurodiscus fujii# | He2921 | KU559357 | KU574845 | KU992709 |
Stereum complicatum | He2234 | KU559368 | KU574828 | KU992706 |
Stereum hirsutum# | Wu 1109-127 | LC430906 | LC430909 | – |
Stereum ostrea | SHe2067 | KU559366 | KU574826 | KU992703 |
Stereum sanguinolentum | He2111 | KU559367 | KU574827 | KU992705 |
Xylobolus frustulatus | He2231 | KU881905 | KU574825 | KU992704 |
The three-marker dataset was composed of 55 taxa and 2502 sites including gaps (of which 29% were parsimony-informative): 953 characters for 28S, 949 characters for ITS and 600 characters for TEF1. Missing sequences were treated as missing data (Table
alpinus (L.), referring to the occurrence at high elevations.
Resembles Aleurodiscus cupulatus Núñez & Ryvarden in having discoid basidiomes, clamped hyphae, similar gloeocystidia, absence of acanthophyses, branched or unbranched hyphidia, and echinulate basidiospores. Aleurodiscus cupulatus features much wider basidiospores than A. alpinus. It differs from its closest phylogenetic relative, A. sichuanensis, by having clamped hyphae, but lacks acanthophyses.
Basidiomes cupuloid or discoid, solitary, occasionally fused, adnate, 350–750 μm thick in section. Hymenial surface Buff, Pale Luteous or Luteous, subceraceous, covered with crystal masses, not cracked; margin concolorous or paler, incurved, filamentous.
Hyphal system monomitic; hyphae nodose-septate. Pileus hyphae subcolorless to brownish, straight, thick-walled, walls usually thinner towards apices, usually with excreted material near apices. Subiculum uniform, with dense to compact texture, 150–500 μm thick; hyphae near substrate more or less vertical, moderately ramified, colorless, 3.5–8 μm diam, with 0.7–1.5 μm thick walls, occasionally guttulate; hyphae near hymenial layer more or less vertical, moderately ramified, colorless, fairly straight, 2.5–5 μm diam, thin- or slightly thick-walled, anastomoses occasional. Hymenial layer thickening, subhymenium differentiated from subiculum, 200–250 μm thick, with dense texture; hyphae fairly vertical, colorless, guttulate, 2–4 μm diam, thin-walled. Crystals sparsely scattered throughout section. Gloeocystidia numerous, immersed or slightly projecting, tubular, sometimes with adventitious septa near basal parts, colorless, (50–)70–200 × 4.5–12.5 μm, thin-walled, guttulate, SA+. Hyphidia numerous, sometimes branched, 40–130 × 2–6.5 μm. Basidia narrowly clavate, occasionally with one or two small protuberances, 85–165 × 16–20 μm, slightly thick-walled (ca. 0.5 μm thick), 4-sterigmate. Basidiospores ellipsoid to narrowly ellipsoid, adaxially concave, finely aculeate, thin-walled, homogenous or guttulate, amyloid, CB–, mostly 22–26 × 11–14 μm. (22–)22.2–26(–27.8) × (11–)11.8–13.5(–14.8) μm, L = 24.2±1.7 μm, W = 12.6±2.2 μm, Q = 1.95 (n = 30) (holotype, Wu 1407-55); (22–)23–24.5(–26) × (10.2–)10.8–13(–14) μm, L = 23.8±1.0 μm, W = 11.8±1.0 μm, Q = 2.02 (n = 30) (Wu 1407-59).
On dead branches of Rhododendron and other angiosperms at very high elevations, China, Jul.
CHINA. YUNNAN PROVINCE: Shangrila County, Pudacuo National Park, Bita Lake, 27°43'N, 99°58'E, 3640 m, on branch of Rhododendron sp., 10 Jul 2014, S.H. Wu, Wu 1407-59 (
Microscopic structures of Aleurodiscus alpinus (holotype, Wu 1407-55) A profile of basidiocarp section B subhymenial and hymenial section C basidiospores (far right: in IKI) D subicular hyphae near substrate E pileus hyphae F subhymenial hyphae G hyphidia H branched hyphidia I gloeocystidia J basidia. Bars: 300 μm (A); 10 μm (B–J).
pinicola (L.), dwelling on Pinus, in reference to the substrate.
Aleurodiscus pinicola and Acanthobasidium penicillatus Burt share the features of moniliform gloeocystidia, acanthophyses with apical spines, dendrohyphidia, basidia with lateral protuberances, and aculeate basidiospores; the latter, however, has clamped hyphae and narrower basidiospores 18–27 × 12–14 (–17) μm. Aleurodiscus pinicola also resembles A. oakesii (Berk. & M.A. Curtis) Pat., however, the latter occurs on deciduous trees and has smaller basidiospores (15–20 × 13–17 μm).
Basidiomes discoid, each one up to 3.5 × 3 mm, adnate, membranaceous-subceraceous, 180–400 μm thick in section. Hymenial surface Buff or Pale Luteous, smooth, occasionally cracked; margin whitish, incurved, filamentous.
Hyphal system monomitic; most hyphae simple-septate, a few hyphal septa in junction of hymenium and subiculum with clamp connections. Subiculum uniform, with fairly dense dense texture, 60–160 μm thick; hyphae more or less vertical at resupinate parts, ± horizontal at marginal curved parts, moderately ramified, more or less interwoven, colorless, 2.5–6 μm diam, slightly thick-walled or containing thick walls up to 2 μm thick, sometimes with small oily drops, anastomoses occasional, some basal hyphae brownish yellow, with thicker walls than those elsewhere. Hymenial layer thickening, subhymenium more or less differentiated from subiculum, with dense texture, 100–270 μm thick; hyphae more or less vertical, colorless, sometimes with a short branch, usually containing minute oily drops, 2.5–5.5 μm diam, thin-walled. Crystal masses scattered throughout hymenial layer. Gloeocystidia numerous, mostly immersed or slightly projecting, cylindrical, usually strongly moniliform toward apices, usually forked, with numerous minute oily drops, colorless, 65–200 × 8.2–15.5 μm, thin- to slightly thick-walled, SA–. Acanthophyses numerous, clavate to broadly clavate, fusiform, stalked, colorless, apical parts with numerous protuberances, 50–100 × 5–30 μm, up to 1.2 μm thick walls, aculei 1–7 × 1–2 μm. Dendrohyphidia numerous, 37–90 × 3–4.8 μm. Hyphidia numerous, 35–80 × 2.4–4.2 μm. Basidia clavate, middle parts usually with several protuberances, 65–130 × 20–32 μm, up to 1.2 μm thick walls, 4-sterigmate. Basidiospores broadly ellipsoid to subglobose, adaxially flattened, aculeate, thin- to thick-walled, up to 3 μm thick walls, with a distinct apiculus, homogenous or with several oil-drops, amyloid, CB–, mostly 22.5–27.5 × 19–24 μm. (22.5–)23.5–27.2(–29) × (18.2–)19.2–22.8(–24) μm, L = 25.4±1.3 μm, W = 20.7±1.6 μm, Q = 1.23 (n = 30) (holotype, Wu 1308-54); (22.2–)23–26.5(–28) × (18.2–)20–22.5(–25.5) μm, L = 24.8±1.3 μm, W = 21.2±1.5 μm, Q = 1.17 (n = 30) (Wu 1106-14).
Microscopic structures of Aleurodiscus pinicola (holotype, Wu 1308-54) A profile of basidiocarp section B subicular hyphae of basidiocarp section C subhymenial and hymenial section D generative hyphae E hyphidia F dendrohyphidia G acanthophyses H gloeocystidia I basidia J basidiospores (left: in IKI, right: in KOH). Scale bars: 200 μm (A); 10 μm (B–J).
On Pinus branches at high elevations, China and Taiwan, Jun to Aug.
TAIWAN. Taichung, Siaosyueshan, Tienchih, 24°17'N, 121°01'E, 2580 m, on branch of Pinus armandii, 8 Jun 2011, S.H. Wu, Wu 1106-14 (
senticosus (L.) = full of thorns, referring to the surface of basidia and cystidia.
Macroscopically featured in having a more or less cracked hymenophore, resulting from the fusion of numerous basidiome patches. Microscopically its basidia are diagnostic in having large lateral echinulate bladder-like swollen structure. Morphologically it resembles Xylobolus spp., although the latter cause a white-pocket rot in wood and have smooth basidiospores.
Basidiomes resupinate, beginning as small orbicular patches, gradually extending and fusing together then becoming effused, adnate, membranaceous, 250–600 μm thick in section. Hymenial surface Buff or Light Buff, slightly tuberculate, with a more or less cracked hymenophore; margin paler, usually determinate, occasionally thinning and byssoid.
Hyphal system monomitic; hyphae simple-septate, colorless. Subiculum with dense texture, 200–350 μm thick; hyphae next to substrate more or less horizontal, slightly interwoven, colorless, moderately ramified, at the junction of basidiocarp patches more or less vertical, 2–4(–5) μm diam, walls up to 1.5 μm thick. Hymenial layer thickening, with dense texture, 150–250 μm thick, not clearly differentiated from the subiculum; hyphae mainly vertical, colorless, 2–4 μm diam, thin- to slightly thick-walled. Gloeocystidia numerous, immersed or slightly projecting, cylindrical or tubular, with stalked bases, apically sometimes forked, sometimes with one or more constrictions near apices or slightly moniliform, colorless, 45–135 × 5–12 μm, with walls up to 1.5 μm thick, SA–. Acanthophyses numerous, subclavate or clavate, basal parts thin-walled, thick-walled toward apices, colorless, median to apical parts echinulate, 25–65 × 4–13 μm (spines excluded). Hyphidia numerous, 35–65 × 2–4 μm. Basidia clavate, 60–82 × 10–15 μm, with walls up to 2 μm thick, 4-sterigmate, usually with large lateral echinulate bladder-like swollen structure. Basidiospores broadly ellipsoid to subglobose, adaxially flattened, aculeate, with 1–3 μm thick walls, homogeneous or sometimes with several oily drops, amyloid, CB–, mostly 13.5–16.5 × 11–13 μm. (13–)13.5–15.8(–17) × (10–)11.2–12.5(–13) μm, L = 14.8±1.00 μm, W = 11.8±0.6 μm, Q = 1.25 (n = 30) (holotype, Wu 1209-7); (13–)14–16(–17.2) × (10–)11.2–13(–15) μm, L = 15.1±1.0 μm, W = 11.9±1.0 μm, Q = 1.26 (n = 30) (GC 1604-46).
Microscopic structures of Aleurodiscus senticosus (holotype, Wu 1209-7) A profile of basidiocarp section B basal of basidiocarp section C section of hymenium D subicular hyphae E gloeocystidia F acanthophyses G basidiospores (left: in KOH, right: in IKI) H hyphidia I basidia. Scale bars: 200 μm (A); 10 μm (B–I).
On angiosperm branches, Taiwan, Apr to Sep.
Taiwan, New Taipei City, Wulai, 24°51'N, 121°33'E, 448 m, on angiosperm branch, 10 Sep 2012, S.H. Wu, Wu 1209-9 (
sichuanensis (L.), referring to Sichuan Province, the type locality.
Aleurodiscus sichuanensis resembles A. oakesii in having acanthophyses, simple-septate generative hyphae, and gloeocystidia occasionally with protuberances. However, clamped hyphae are rarely present in A. oakesii. Protuberances of acanthophyses of A. oakesii are antler-like, while aculei of acanthophyses in A. sichuanensis are fairly small. Basidiospores of A. sichuanensis are D-shaped or broadly ellipsoid, while those of A. oakesii are ovoid-ellipsoid and slightly smaller (18–27 ×12–14(–17) μm). Aleurodiscus sichuanensis, however, is most closely related to A. alpinus and differs from it by having acanthophyses and simple-septate hyphae.
Basidiomes resupinate, effused, adnate, membranaceous-subceraceous, 150–350 μm thick in section. Hymenial surface smooth, Buff or Buff Yellow, occasionally cracked; margin concolorous, determinate.
Hyphal system monomitic; hyphae simple-septate. Subiculum uniform, with dense texture, thin or up to 150 μm thick; hyphae interwoven, colorless, richly ramified, tortuous, usually full of small oily drops, 2.5–5.5 μm diam, thin-walled. Hymenial layer with dense texture, 100–200 μm thick; hyphae vertical, colorless, ± straight, 2.5–4.5 μm diam, thin-walled. Crystal masses scattered in subiculum, yellowish. Gloeocystidia numerous, immersed or projecting, yellowish or pale brownish yellow, cylindrical, narrowly clavate or tubular, with oily contents or homogeneous, SA+, basal or median portion occasionally with small aculei, 70–135 × 7–14 μm, with 0.5–1 μm thick walls. Acanthophyses numerous, irregularly cylindrical or narrowly clavate, sometimes subfusiform, colorless, apical parts with numerous aculei, 30–70 × 3–8(–12) μm (aculei excluded), thin-walled. Hyphidia numerous, occasionally branched, 35–85 × 2.5–4.5 μm. Basidia clavate, 4-sterigmate, 100–130 × 20–25 μm, with 0.8–1.2 μm thick walls. Basidiospores D-shaped or broadly ellipsoid, adaxially flattened, finely aculeate, thin-walled or 1–2 μm thick, sometimes with oily contents, amyloid, CB–, mostly 25.5–28.5 × 15–18 μm. (25–)26–28.2(–29) × (14.5–)15.2–17(–19) μm, L = 27.1±1.0 μm, W = 15.9±1.1 μm, Q = 1.71 (n = 30) (holotype, Wu 0010-18).
On dead branches of Quercus and other angiosperms at high elevations, China, Jul to Oct.
CHINA. SICHUAN PROVINCE: Wolungshan, Tengsheng, 2700 m, on angiosperm branch, 11 Oct 2000, S.H. Wu & S.C. Wu, Wu 0010-42 (
A number of phylogenetic studies of Aleurodiscus s.l. have been conducted in the past twenty years (
Aleurodiscus alpinus is reminiscent of Aleurodiscus s.s. (A. amorphus (Pers.) J. Schröt. and A. grantii Lloyd) due to the discoid basidiocarp and echinulate basidiospores, as well as the absence of acanthophyses. However, the gloeocystidia of Aleurodiscus s.s. are paraphysis-like, narrow and moniliform, while those of A. alpinus are much wider and not moniliform. In addition, A. alpinus has unbranched or branched hyphidia, which are lacking in Aleurodiscus s.s. Aleurodiscus alpinus formed a clade with A. sichuanensis (Fig.
Aleurodiscus pinicola presents protuberances in the basidia and this is reminiscent of Acanthobasidium. However, this feature is not limited to Acanthobasidium spp. For example, basidia of Aleurodiscus mirabilis (Berk. & M.A. Curtis) Höhn. and A. wakefieldiae Boidin & Beller occasionally possess protuberances, but they and A. pinicola do not belong to Acanthobasidium (Fig.
Aleurodiscus senticosus is macroscopically distinct in having more or less cracked hymenophore from the fusion of smaller basidiocarp patches; microscopically, its basidia bear a large, spiny, bladder-like structure that is unique among Aleurodiscus s.l. The present phylogenetic analyses (Fig.
Aleurodiscus sichuanensis cannot be accommodated in any segregate genus of Aleurodiscus s.l., according to the combined features of effused basidiocarp, simple-septate hyphae, acanthophyses, gloeocystidia with aculei, and echinulate basidiospores.
In conclusion, the status of each segregate genus of Aleurodiscus s.l. should be further examined by multi-gene analysis of more species to evaluate which ones can be recognized and which cannot. Although the four new species we introduce cannot be accommodated in any segregate genus of Aleurodiscus s.l. according to the present combined morphological and phylogenetic studies, they are still placed under the broad sense of Aleurodiscus at the present time.
This study was financed by Ministry of Science and Technology of R.O.C. (Grant no 104-2621-B-178-001-MY3). The authors are grateful to Ms. Siou-Zhen Chen (