Corresponding author: Yu-Cheng Dai ( firstname.lastname@example.org )
Academic editor: Cvetomir Denchev
© 2017 Yuan Yuan, Xiao-Hong Ji, Jia-Jia Chen, Yu-Cheng Dai.
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: Yuan Y, Ji XH, Chen JJ, Dai YC (2017) Three new species of Megasporia (Polyporales, Basidiomycota) from China. MycoKeys 20: 37-50. https://doi.org/10.3897/mycokeys.20.11816
Megasporia is a newly established polypore genus characterized by resupinate fruiting bodies with big pores, a dimitic hyphal structure with generative hyphae bearing clamp connections, more or less dextrinoid and cyanophilous skeletal hyphae, cylindrical, hyaline, thin-walled, smooth basidiospores, and growth mostly on fallen angiosperm branches. Species number is extremely rich in subtropical and tropical Asia. Three new species, namely M. rimosa, M. tropica and M. yunnanensis are described from China, and their illustrated descriptions are given. Differences between these new species and phylogenetically related and morphologically similar species are discussed. A key to the known species of Megasporia is provided.
Phylogeny, Polyporaceae, taxonomy, white-rot fungi
Megasporia B.K. Cui et al. was recently derived from Megasporoporia Ryvarden & J.E. Wright, nested within the core polyporoid clade (
During the study of polypores from southern China, six specimens collected on fallen angiosperm branches were examined, phylogenetic relationships were analyzed based on ITS and nLSU rDNA sequences data, and three new species of Megasporia were discovered. The aim of this work demonstrates the diversity of Megasporia in China. Illustrated descriptions of these species and a key to known species in the genus are provided in the present paper.
Specimens examined were deposited in the herbarium of the Institute of Microbiology, Beijing Forestry University (BJFC). Macro-morphological descriptions were based on field notes and herbarium specimens. Color terms follow
A CTAB rapid plant genome extraction kit (Aidlab Biotechnologies Co., Ltd, Beijing) was used to obtain total genomic DNA from dried specimens, according to the manufacturer’s instructions with some modifications (
Sequences generated in this study were aligned with additional sequences downloaded from GenBank (Table
A list of species, specimens and GenBank accession numbers of sequences used in this study.
|Abundisporus violaceus||MUCL 38617||FJ411100||FJ393867|
|Cinereomyces lindbladii||Larsson 12078||FN907906||FN907906|
|Datronia mollis||RLG 6304sp||JN165002||JN164791|
|Dichomitus eucalypti||Oslo 910674||JQ780412||JQ780441|
|D. squalens||Cui 9639||JQ780407||JQ780426|
|Donkioporia expansa||MUCL 35116||FJ411104||FJ393872|
|Grammothele quercina||Dai 11768||JQ314364||JQ780423|
|Grammothelopsis subtropica||Cui 9035||JQ845094||JQ845097|
|Lentinus tigrinus||DSH 93-181||AY218419||AF518627|
|Megasporia cystidiolophora||Cui 2688||JQ780389||JQ780431|
|M. ellipsoidea||Cui 5222||JQ314367||JQ314390|
|M. ellipsoidea||Cui 13685||KY449433||KY449444|
|M. guangdongensis||Cui 9130||JQ314373||JQ780428|
|M. hengduanensis||Cui 8076||JQ780392||JQ780433|
|M. hexagonoides||Dai 16449||KY449434||KY449445|
|M. hexagonoides||Yuan 4233||KY449435||KY449446|
|M. major||Cui 10253||JQ314366||JQ780437|
|M. rimosa||Dai 15357||KY449436||KY449447|
|M. tropica||Cui 13660||KY449437||KY449448|
|M. tropica||Cui 13740||KY449438||KY449449|
|M. violacea||Cui 6601b||JQ780395||JQ780434|
|M. violacea||Cui 13607||KY449439||KY449450|
|M. violacea||Cui 13648||KY449440||KY449451|
|M. yunnanensis||Cui 12594||KY449441||KY449452|
|M. yunnanensis||Cui 12614||KY449442||KY449453|
|M. yunnanensis||Dai 13870||KY449443||KY449454|
|Megasporoporia bannaensis||Dai 12306||JQ314362||JQ314379|
|M. minor||Dai 12170||JQ314363||JQ314380|
|Megasporoporiella lacerata||Yuan 3880||JQ314377||JQ314395|
|M. pseudocavernulosa||Yuan 1270||JQ314360||JQ314394|
|M. rhododendri||Dai 4226||JQ314356||JQ314392|
|M. subcavernulosa||Cui 9252||JQ780378||JQ780416|
|Melanoderma microcarpum||Dai 9811||HQ678173||HQ678175|
|Perenniporia medulla-panis||Cui 3274||JN112792||JN112793|
|P. tephropora||Cui 8040||JN048763||HQ654118|
|Perenniporiella chaquenia||MUCL 49758||FJ411085||FJ393857|
|Polyporus brumalis||KHL 8558||AF347108||AF347108|
|Porogramme albocincta||TL 9894/03||JX109854||JX109854|
|Pseudofavolus cucullatus||WD 2157||AB587637||AB368114|
|Pycnoporus cinnabarinus||AFTOL-ID 772||DQ411525||AY586703|
|Pyrofomes demidoffii||MUCL 41034||FJ411105||FJ393873|
|Sebipora aquosa||Miettinen 8680||HQ659240||HQ659240|
Maximum parsimony phylogenetic analysis followed
The combined ITS and nLSU dataset included 45 sequences of ITS and 44 sequences of nLSU regions from 45 fungal samples representing 37 species. The dataset had an aligned length of 1919 characters in the dataset, of which 1330 characters are constant, 178 are variable and parsimony-uninformative, and 411 are parsimony-informative. Maximum parsimony analysis yielded 6 equally parsimonious trees (TL = 2082, CI = 0. 451, RI = 0.625, RC = 0.282, HI = 0.549), and one of the maximum parsimonious trees is shown in Figure
Strict consensus tree illustrating the phylogeny of Megasporia and its related species generated by maximum parsimony based on ITS+nLSU sequences. Branches are labeled with parsimony bootstrap proportions (before slanting line) high than 50% and bayesian posterior probabilities (after slanting line) more than 0.90.
Samples of Megasporia clustered together (89% ML and 1 BPPs, Figure
Differs from other Megasporia species by its extremely thin and cracked basidiocarp (less than 0.5 mm thick) when dry.
CHINA. Guangxi Auto. Reg., Shangsi County, Shiwandashan Nature Reserve, on fallen angiosperm branch, 06 June 2015, Y.C. Dai 15357 (BJFC019468).
Annual, resupinate, corky, without odor or taste when fresh, becoming hard corky and cracked upon drying, up to 17 cm long, 4 cm wide, and 0.4 mm thick at centre. Sterile margin thinning out, white when fresh, cream when dry, very narrow to almost lacking. Pore surface white to cream when fresh, cream when dry; pores angular, 3–4 per mm; dissepiments thick, entire. Subiculum pale buff, corky, up to 0.1 mm thick. Tubes cream, paler than subiculum, corky, up to 0.3 mm long.
Hyphal system dimitic; generative hyphae bearing clamp connections; skeletal hyphae weakly dextrinoid, CB+; tissues unchanged in KOH.
Generative hyphae infrequent, hyaline, thin-walled, occasionally branched, sometimes encrusted by crystals, 1.5–2.5 µm in diam; skeletal hyphae dominant, thick-walled with a narrow to medium lumen, moderately branched, mostly flexuous, interwoven, slightly gelatinized, sometimes encrusted by crystals, 2.5–3.5 µm in diam.
Generative hyphae hyaline, thin-walled, occasionally branched, 1.5–2.5 µm in diam; skeletal hyphae dominant, thick-walled with a narrow lumen, unbranched, more or less straight, subparallel along the tubes, 2–3 µm in diam. Hyphal pegs absent, dendrohyphidia present along hymenium, cystidia absent; cystidioles present, mostly ventricose, thin-walled, smooth. Basidia broadly clavate to pear-shaped, with four sterigmata and a basal clamp connection, 20–28 × 5–7.5 µm; basidioles in shape similar to basidia, but smaller. Small tetrahedric or polyhedric crystals frequently present among subhymenium and hymenium.
Basidiospores cylindrical, hyaline, thin-walled, smooth, sometimes with one or two guttula, IKI–, CB–, (16.5–)16.8–20.2(–21) × (4.1–)4.3–5.5(–5.9) μm, L = 18.49 μm, W = 4.88 μm, Q = 3.97 (n = 30/1).
Rimosa (Lat.): referring to the cracked hymenophore when dry.
Differs from other Megasporia species by strongly dextrinoid skeletal hyphae, and by lacking dendrohyphidia, cystidioles and hyphal pegs.
CHINA. Hainan Prov., Wuzhishan County, Wuzhishan Nature Reserve, on fallen angiosperm branch, 10 Nov 2015, B.K. Cui 13660 (BJFC022532).
Annual, resupinate, corky, without odor or taste when fresh, becoming hard corky to leathery upon drying, up to 5 cm long, 3 cm wide, and 1.5 mm thick at centre. Sterile margin thinning out, cream when dry, up to 1 mm wide. Pore surface clay-pink to fawn when dry; pores round, 2–3 per mm; dissepiments thin, entire to lacerate. Subiculum cream, corky, up to 0.5 mm thick. Tubes clay-pink, slightly darker than subiculum, corky, up to 1 mm long.
Hyphal system dimitic; generative hyphae bearing clamp connections; skeletal hyphae strongly dextrinoid, CB+; tissues unchanged in KOH.
Generative hyphae infrequent, hyaline, thin-walled, occasionally branched, 2.5–3 µm in diam; skeletal hyphae dominant, thick-walled with a narrow to medium lumen, unbranched, more or less flexuous, loosely interwoven, 3–4 µm in diam.
Generative hyphae hyaline, thin-walled, occasionally branched, 1.5–2 µm in diam; skeletal hyphae dominant, thick-walled with a narrow lumen, occasionally branched, more or less straight, subparallel along the tubes, 2–3 µm in diam. Hyphal pegs, dendrohyphidia and cystidia absent; cystidioles present, subulate, thin-walled, smooth. Basidia broadly clavate, with four sterigmata and a basal clamp connection, sometimes with a big guttule, 20–25 × 7–9.5 µm; basidioles pear-shaped, slightly smaller than basidia. Small tetrahedric or polyhedric crystals frequently present among subhymenium and hymenium.
Basidiospores cylindrical, hyaline, thin-walled, smooth, mostly with a big guttula, IKI–, CB–, (14.2–)14.7–18.8(–19.7) × (4.9–)5–6.5(–7.1) μm, L = 16.55 μm, W = 5.65 μm, Q = 2.83–3.04 (n = 60/2).
CHINA. Hainan Prov., Ledong County, Jianfengling Forest Park, on fallen angiosperm branch, 21 Nov 2015, B.K. Cui 13740 (BJFC022533).
Tropica (Lat.): referring to the species occurring in the tropics.
Differs from other Megasporia species by brownish tints on pore surface and lacking tetrahedric or polyhedric crystals.
CHINA. Yunnan Province, Kunming, Wild Duck Lake Park, on fallen angiosperm branch, 28 July 2014, Y.C. Dai 13870 (BJFC017600).
Annual, resupinate, corky, without odor or taste when fresh, becoming hard corky upon drying, up to 3 cm long, 2 cm wide, and 2 mm thick at centre. Sterile margin thinning out, white when dry, up to 1 mm wide. Pore surface white to cream but with brownish tints when dry; pores round, 2–3 per mm; dissepiments thin, lacerate. Subiculum white, corky, up to 1 mm thick. Tubes cream, corky, up to 1 mm long.
Hyphal system dimitic; generative hyphae bearing clamp connections; skeletal hyphae weakly dextrinoid, CB+; tissues unchanged in KOH.
Generative hyphae frequent, hyaline, thin-walled, occasionally branched, 2–3 µm in diam; skeletal hyphae dominant, thick-walled with a wide to narrow lumen, occasionally branched, mostly flexuous, interwoven, 3–4 µm in diam.
Generative hyphae infrequent, hyaline, thin-walled, occasionally branched, 2–3 µm in diam; skeletal hyphae dominant, thick-walled with a wide to medium lumen, occasionally branched, flexuous, interwoven, 2.5–3.5 µm in diam. Hyphal pegs and cystidia absent, dendrohyphidia present; cystidioles present, mostly ventricose, thin-walled, smooth. Basidia broadly clavate, with four sterigmata and a basal clamp connection, 30–35 × 9–11 µm; basidioles in shape similar to basidia, but smaller. Tetrahedric or polyhedric crystals absent.
Basidiospores cylindrical, hyaline, thin-walled, smooth, IKI–, CB–, (15.1–)16.5–20.8(–21.5) × (5.1–)5.5–7.1(–7.5) μm, L = 18.38 μm, W = 6.19 μm, Q = 2.88–3.02 (n = 90/3).
CHINA. Yunnan Province, Nanhua County, Dazhongshan Nature Reserve, on fallen angiosperm branch, 11 Sept 2015, B.K. Cui 12594 (BJFC022530). Chuxiong, Zixishan Nature Reserve, on fallen branch of Rhododendron, 12 Sept 2015, B.K. Cui 12614A (BJFC022531).
Yunnanensis (Lat.): referring to the locality (Yunnan Province, China) where the species was found.
In this study, seven previously accepted species of Megasporia (M. cystidiolophora (B.K. Cui & Y.C. Dai) B.K. Cui & Hai J. Li, M. ellipsoidea (B.K. Cui & P. Du) B.K. Cui & Hai J. Li, M. guangdongensis B.K. Cui & Hai J. Li, M. hengduanensis B.K. Cui & Hai J. Li, M. hexagonoides (Speg.) B.K. Cui, Y.C. Dai & Hai J. Li, M. major (G.Y. Zheng & Z.S. Bi) B.K. Cui, Y.C. Dai & Hai J. Li and M. violacea (B.K. Cui & P. Du) B.K. Cui, Y.C. Dai & Hai J. Li) were referred to morphological examination and phylogenetic analysis. Three new Megasporia species, M. rimosa, M. tropica and M. yunnanensis, are described based on morphological differences and molecular phylogenetic analysis. Sampled specimens of Megasporia formed a well-supported lineage (89% ML and 1.0 BPPs), indicating that all are phylogenetically distinct from other genera, as suggested by the combined ITS and nLSU dataset (Figure
Among the accepted Megasporia species, M. hexagonoides and M. major have big basidiospores (16.6–21.8 × 5.2–6.8 μm, 15.2–20 × 5.5–7.1 μm,
It seems that species of Megasporia prefer small branches rather than big logs; all specimens of the genus having been collected mostly on fallen branches and dead branches on living trees, and such branches being not strongly decayed. The basidiocarps of the genus are usually not very big and usually form small patches, although some patches may be merged finally. All the species of Megasporia have been found on angiosperm wood (never on gymnosperms), and they have a distribution in subtropical and tropical forests, especially in open environments, e.g. fallen branches along roads or paths. In addition, the species diversity of the genus is very rich in subtropical and tropical Asia, many more undescribed taxa are found from our samples based on phylogenetic analyses, but all these samples are sterile as a common feature of the genus, and the best season for producing basidiospores on these taxa are unknown.
Although Megasporoporiella, Megasporoporia and Megasporia are very similar, we found some difference among these genera both in morphology and ecology. The main difference is that Megasporoporia has di-trimitic hyphal structure and strongly dextrinoid skeletal hyphae, while dimitic hyphal structure and weakly to moderately dextrinoid skeletal hyphae are in Megasporoporiella and Megasporia. In addition, Megasporoporiella has a distribution in temperate region, while Megasporia in subtropical to tropics.
|1||Pores 0.5–1.5 per mm||2|
|–||Pores 2–7 per mm||4|
|2||Basidiospores ellipsoid, gloeocystidia present||M. ellipsoidea|
|–||Basidiospores cylindrical, gloeocystidia absent||3|
|3||Pores 0.5–1 per mm, pore surface ash gray||M. hexagonoides|
|–||Pores 1–1.5 per mm, pore surface cream||M. major|
|4||Basidiospores < 15 μm in length, hyphal pegs present||5|
|–||Basidiospores > 15 μm in length, hyphal pegs absent||8|
|5||Pores 5–7 per mm, pores violet when fresh; dendrohyphidia present||M. violacea|
|–||Pores 2–5 per mm, pores cream to buff when fresh; dendrohyphidia absent||6|
|6||Pores 2–3 per mm, skeletal hyphae moderately dextrinoid||M. hengduanensis|
|–||Pores 3–5 per mm, skeletal hyphae strongly dextrinoid||7|
|7||Basidiospores 3.4–4.5 μm in width, cystidioles collapsed||M. guangdongensis|
|–||Basidiospores 4.1–5.6 μm in width, cystidioles not collapsed||M. cystidiolophora|
|8||Basidiocarp < 0.5 mm thick and cracked when dry||M. rimosa sp. nov.|
|–||Basidiocarp > 1 mm thick and not cracked when dry||9|
|9||Tetrahedric or polyhedric crystals present, dendrohyphidia absent||M. tropica sp. nov.|
|–||Tetrahedric or polyhedric crystals absent, dendrohyphidia present||M. yunnanensis sp. nov.|
We thank Prof. Bao-Kai Cui (Beijing) for providing important materials for our study. The research is supported by the Fundamental Research Funds for the Central Universities (Project No. 2016ZCQ04).