Research Article |
Corresponding author: Shuang-Hui He ( heshuanghui@bjfu.edu.cn ) Academic editor: R. Henrik Nilsson
© 2018 Shi-Liang Liu, 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:
Liu S-L, He S-H (2018) Taxonomy and phylogeny of Dichostereum (Russulales), with descriptions of three new species from southern China. MycoKeys 40: 111-126. https://doi.org/10.3897/mycokeys.40.28700
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Nine species of Dichostereum were subjected to phylogenetic analyses, based on a combined dataset of ITS1-5.8S-ITS2-nrLSU-tef1 sequences. The morphology of specimens collected from China and Australia were studied. Three species, D. austrosinense, D. boidinii and D. eburneum, collected from southern China, are described and illustrated as new to science, based on the morphological and molecular evidence. Dichostereum austrosinense is characterised by the relatively large gloeocystidia (80–130 × 8–15 µm) and basidiospores (7.3–8 µm in diam.) with large warts and crests. Dichostereum boidinii is distinguished by its thick basidiomata and relatively small basidiospores (5.5–6.5 µm in diam.) with large warts and crests. Dichostereum eburneum is unique in having pale basidiomata growing on bark of living Castanopsis, abundant crystals in the context and basidiospores with dense and large ornamentations. A key to the 5 species of Dichostereum in China is given.
Amyloid basidiospores, corticioid fungi, dichohyphae, Peniophoraceae , Vararia
Dichostereum Pilát, typified with D. durum (Bourdot & Galzin) Pilát, is a small and well-delimited corticioid genus in Russulales. It is characterised by resupinate basidiomata with smooth or grandinioid hymenophore, dimitic hyphal system with dextrinoid dichohyphae and clamped generative hyphae, gloeocystidia and ellipsoid or subglobose, ornamented basidiospores with a strong amyloid reaction in Melzer’s reagent (
Dichostereum was once treated as a subgenus of Vararia P. Karst. (Peniophoraceae, Russulales) by some mycologists since the two genera are very similar in morphology except that the latter has smooth basidiospores (
Previously, two species, Dichostereum boreale (Pouzar) Ginns & M.N.L. Lefebvre (= D. granulosum) and D. pallescens (Schwein.) Boidin & Lanq., were reported in temperate China (
Voucher specimens were deposited in the herbaria of Beijing Forestry University, Beijing, China (
The CTAB plant genome rapid extraction kit DN14 (Aidlab Biotechnologies Co. Ltd, Beijing) was used for DNA extraction and PCR amplification from dried specimens or cultures. The ITS, partial nrLSU and tef1 markers were amplified with the primer pairs ITS5/ITS4 (
The molecular phylogeny was inferred from a combined dataset of ITS1-5.8S-ITS2-nrLSU-tef1 sequences of representative members of Peniophoraceaesensu
Species and sequences used in the phylogenetic analyses. Newly generated sequences are set in bold. Holotypes are marked with *.
Taxa | Voucher | Locality | ITS | nrLSU | tef1 |
---|---|---|---|---|---|
Asterostroma bambusicola | He 4132 | Thailand | KY263865 | KY263871 | MH669240 |
A. cervicolor | He 4020 | China | KY263859 | KY263869 | – |
Baltazaria eurasiaticogalactina | CBS 666.84 | France | – | AY293211 | – |
B. octopodites | FLOR 56449 | Brazil | MH260025 | MH260047 | – |
Dichostereum austrosinense | He 4871* | China | MH538317 | MH538334 | – |
He 4316 | China | MH538316 | MH538335 | – | |
He 3551 | China | MH538314 | – | MH550363 | |
D. boidinii | He 5026* | China | MH538324 | MH538330 | – |
He 1662 | China | MH538309 | – | MH550360 | |
He 4410 | China | MH538315 | MH538331 | MH550361 | |
He 462 | China | MH538311 | – | – | |
Dai 16117 | China | MH538312 | MH538327 | MH550362 | |
D. durum | Fungi Gallici 1985 | France | AF506429 | AF506429 | – |
D. eburneum | He 5374* | China | MH538318 | MH538337 | MH550366 |
D. effuscatum | GG 930915 | France | AF506390 | AF506390 | – |
FP 101758 Sp | USA | MH538323 | MH538336 | MH550367 | |
CBS 516.80 | USA | – | AF323739 | – | |
D. granulosum | NH 7137 | Canada | AF506391 | AF506391 | – |
FP 133479 Sp | USA | MH538321 | MH538333 | MH550368 | |
He 1887 | China | MH538313 | MH538332 | – | |
D. pallescens | Kropp 2 | USA | MH538320 | MH538326 | MH550365 |
CBS 717.81 | USA | – | AF518614 | – | |
He 3266 | China | MH538310 | MH538325 | MH550364 | |
D. aff. pallescens | KHL 10258 | Puerto Rico | AF506428 | AF506428 | – |
D. rhodosporum | Dai 18625A | Australia | MH538319 | MH538329 | MH550370 |
D. sordulentum | FP 11735 Sp | USA | MH538322 | MH538328 | MH550369 |
Duportella tristicula | He 4775 | China | MH669235 | MH669239 | MH669245 |
Echinodontium tinctorium | HHB 12866 Sp | USA | KY172888 | KY172903 | MH550371 |
Gloiothele lactescens | EL 8-98 | Sweden | AF506453 | AF506453 | – |
G. lamellosa | KHL11031 | Venezuela | AF506454 | AF506454 | – |
Lachnocladium cf. brasiliense | CALD 161213-1 | Brazil | MH260037 | MH260055 | – |
L. schweinfurthianum | KM 49740 | Cameroon | MH260033 | MH260051 | – |
L. sp. | KHL10556 | Jamaica | AF506461 | AF506461 | – |
Parapterulicium subarbusculum | FLOR 56456 | Brazil | MH260026 | MH260026 | – |
FLOR 56459 | Brazil | MH260027 | MH260049 | – | |
Peniophora polygonia | He 3668 | China | MH669233 | MH669237 | MH669243 |
P. rufa | He 2788 | China | MH669234 | MH669238 | MH669244 |
Scytinostroma portentosum | EL11-99 | Sweden | AF506470 | AF506470 | – |
Vararia investiens | He 2104 | USA | – | MH669236 | MH669242 |
FP 151122 | USA | MH971976 | MH971977 | – | |
Vesiculomyces citrinus | He 3716 | China | KY860369 | KY860429 | MH669241 |
For both Maximum Likelihood (ML) and Bayesian Inference (BI), a partitioned analysis was performed with the following five partitions: ITS1, 5.8S, ITS2, nrLSU and tef1. The ML analysis was performed using RAxML v.8.2.10 (
The ITS-nrLSU-tef1 sequence dataset contained 37 ITS, 38 nrLSU and 18 tef1 sequences from 40 samples representing 26 ingroup taxa and the outgroup (Table
In the tree (Fig.
Phylogeny of Dichostereum and representatives of Peniophoraceae inferred from ITS-nrLSU-tef1 sequences. Topology is from ML analysis with maximum likelihood bootstrap support values (≥50, former), parsimony bootstrap support values (≥50, middle) and Bayesian posterior probability values (≥0.95, latter) shown along the branches. Different species of Dichostereum are indicated as coloured blocks. The new species are set in bold. Scale bar: 0.05 nucleotide substitutions per site.
CHINA. Guangxi Autonomous Region, Jinxiu County, Dayaoshan Nature Reserve, Shengtangshan, on fallen angiosperm trunk, 15 Jul 2017, He 4871 (holotype,
“austrosinense” referring to the distribution in southern China.
Perennial, resupinate, effused, closely adnate, inseparable from substrates, coriaceous to soft corky, at first as irregular small patches, later confluent up to 15 cm long, 4.5 cm wide, up to 1 mm thick. Hymenophore surface smooth, greyish-orange [5B(4–5)], brownish-yellow [5C(7–8)] to light brown [6D(4–8)], not cracking; margin abrupt, concolorous or darker than hymenophore surface.
Hyphal system dimitic. Context thickening, compact, composed of generative hyphae, dichohyphae, embedded basidiospores and scattered crystals. Generative hyphae rare, with clamp connections, hyaline, thin- to slightly thick-walled, 2–3 µm in diam. Dichohyphae dominant, hyaline to yellow, distinctly thick-walled, dichotomously branched with acute tips, weakly dextriniod. Catahymenium composed of dichohyphae, gloeocystidia, basidia and basidioles. Dichohyphae in this layer abundant, similar to those in the context, but strongly dextrinoid, more slender and more frequently branched, 20–50 μm across, 2–4 µm wide at lowest part. Gloeocystidia abundant, subcylindrical to subfusiform, hyaline, slightly thick-walled, with or without solidified contents, 80–130 × 8–15 µm. Basidia narrowly cylindrical, usually slightly sinuous, hyaline, thin-walled, with 4 sterigmata and a basal clamp connection, 50–80 × 5–8 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores abundant, subglobose with a distinct apiculus, hyaline to pale yellowish-brown in KOH, thick-walled, strongly amyloid, (7–) 7.3–8 (–9) µm in diam.; walls ornamented with large warts and crests.
CHINA. Hainan Province, Lingshui County, Diaoluoshan Nature Reserve, on fallen angiosperm trunk, 17 Mar 2016, He 3551 (
Dichostereum austrosinense is overall characterised by the relatively large gloeocystidia and basidiospores with large warts and crests. Dichostereum peniophoroides (Burt) Boidin & Lanq. is similar to D. austrosinense but differs in having wider gloeocystidia (7–22 µm), slightly larger basidiospores (7–9 µm) with larger ornamentations and a distribution in Caribbean regions (
CHINA. Hubei Province, Wufeng County, Breeding base of Magnolia, on angiosperm stump, 14 Aug 2017, He 5026 (holotype,
“boidinii” (Lat.), named to honour Dr. Jacques Boidin (Lyon, France) for his contribution to the taxonomy of Dichostereum.
Perennial, resupinate to effused-reflexed with slightly elevated margin, closely adnate, inseparable from substrates, coriaceous to soft corky, up to 8 cm long, 4 cm wide, 1.5 mm thick. Hymenophore surface smooth, greyish-orange [6B(3–4)], brownish-orange [6C(4–6)] to light brown [6D(4–6)], not cracking; margin abrupt, concolorous or darker than hymenophore surface.
Hyphal system dimitic. Context thickening, compact, composed of generative hyphae, dichohyphae, embedded basidiospores and scattered crystals. Generative hyphae rare, with clamp connections, hyaline, thin-walled, 2–3 µm in diam. Dichohyphae dominant, hyaline to yellow, distinctly thick-walled, dextriniod. Catahymenium composed of dichohyphae, gloeocystidia, basidia and basidioles. Dichohyphae in this layer abundant, similar to those in the context, but strongly dextrinoid, more frequently branched with short terminal branches, 20–40 μm across, 2–4 µm wide at lowest part. Gloeocystidia abundant, fusiform to subulate, hyaline, slightly thick-walled, with solidified contents, 20–60 × 7–12 µm. Basidia subclavate to subcylindrical, hyaline, thin-walled, with 4 sterigmata and a basal clamp connection, 25–40 × 5–7 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores subglobose with a distinct apiculus, hyaline to pale yellowish-brown in KOH, thick-walled, strongly amyloid, (5–) 5.5–6.5 (–7) µm in diam.; walls ornamented with warts and crests.
CHINA. Anhui Province, Huangshan County, Huangshan Nature Reserve, on fallen angiosperm trunk, 21 Oct 2011, He 462 (
Dichostereum boidinii is widely distributed in southern China and mainly characterised by the thick, brownish basidiomata and relatively small basidiospores with large warts and crests. Dichostereum pallescens is similar to D. boidinii but differs in having slender dichohyphae and smaller and sparser ornamentations of basidiospores (
CHINA. Fujian Province, Wuyishan County, Wuyishan Nature Reserve, on bark of living Castanopsis, 6 Apr 2018, He 5374 (holotype,
“eburneum” referring to the white colour of hymenophore.
Perennial, resupinate, effused, closely adnate, inseparable from substrate, coriaceous, at first as irregular small patches, later confluent up to 7 cm long, 2 cm wide, 200–500 µm thick. Hymenophore surface smooth, white (5A1), orange white (5A2) to greyish-orange [5B(3–4)], cracking with age; margin thinning out, concolorous with hymenophore.
Hyphal system dimitic. Context thickening, compact, composed of generative hyphae, dichohyphae, embedded basidiospores and abundant crystals. Generative hyphae rare, with clamp connections, hyaline, thin- to slightly thick-walled, 2–3 µm in diam. Dichohyphae dominant, hyaline to yellow, distinctly thick-walled, dextriniod, frequently branched, aseptate, 1–2 µm in diam. Catahymenium composed of dichohyphae, gloeocystidia, basidia and basidioles. Dichohyphae in this layer abundant, hyaline to pale yellow, distinctly thick-walled, strongly dextriniod, dichotomously branched with acute terminal tips, 15–30 μm across, 2–4 µm wide at lowest part. Gloeocystidia abundant, fusiform to subclavate, hyaline, thin-walled, with solidified contents, 20–50 × 5–10 µm. Basidia subcylindrical with basal part slightly swollen, hyaline, thin-walled, with 4 sterigmata and a basal clamp connection, 30–45 × 6–9 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores subglobose with a distinct apiculus, hyaline to pale yellowish-brown in KOH, thick-walled, strongly amyloid, 6–7 (–8) µm in diam.; walls ornamented with dense, large warts and crests.
Dichostereum eburneum is characterised by the pale basidiomata on bark of living tree, the presence of abundant crystals in context and basidiospores with dense and large ornamentations. Ecologically and macroscopically, D. eburneum resembles Dendrothele Höhn. & Litsch., but the microscopic features are largely different (
1 | Hymenophore grandinioid; basidiospores ellipsoid | D. granulosum |
– | Hymenophore smooth; basidiospores subglobose | 2 |
2 | Basidiomata white; on bark of living Castanopsis | D. eburneum |
– | Basidiomata brownish; on dead wood | 3 |
3 | Gloeocystidia ≥80 μm long | D. austrosinense |
– | Gloeocystidia <80 μm long | 4 |
4 | Basidiospores 6.5–7.5 µm in diam, ornamentation sparse | D. pallescens |
– | Basidiospores 5.5–6.5 µm in diam, ornamentation dense | D. boidinii |
To date, 14 species of Dichostereum have been described worldwide including the three new species in the present paper (
The family Peniophoraceaesensu
The authors thank Drs. Rita Rentmeester and Karen Nakasone (Center for Forest Mycology Research, Northern Research Station, U.S. Forest Service, Madison, USA) for culture and literature loan. The authors acknowledge Dr. Yu-Cheng Dai (Beijing Forestry University, China) for providing specimens. This study was supported by the National Natural Science Foundation of China (Nos. 31670013 & 31470144) and the Fundamental Research Funds for the Central Universities (No. 2017PT09).