Hyphodontia zhixiangii sp. Nov. (Schizoporaceae, Basidiomycota) from Uzbekistan

Abstract

Hyphodontia zhixiangii is described as a new species from three Uzbek specimens recently collected on Juniperus. This species is characterized by annual, resupinate basidiocarps with a grandinioid to odontioid hymenophore, a monomitic hyphal system with clamp-connected generative hyphae, frequent lagenocystidia and subcapitate septocystidia, and ellipsoid to broadly ellipsoid, thin-walled, smooth basidiospores measuring 4.6–5.5 × 3.3–4 μm. Morphologically, H. zhixiangii resembles H. alutaria and H. arguta. H. alutaria differs mainly in its colliculose hymenophore and slightly smaller basidiospores measuring 4.5–5 × 3–3.5 μm. H. arguta differs in the absence of septocystidia and bearing longer aculei measuring 0.5–2 µm in length. In the ITS-based phylogeny, H. zhixiangii nested within the Hyphodontia clade as a distinct lineage. Three ITS sequences labeled as H. arguta did not cluster together. As it is not known if any of these sequences were obtained from specimens collected in Sweden, the neotype locality, it is impossible to decide which one, if any, represents the genuine H. arguta

Full text

Phytotaxa 299 (2): 273–279
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Copyright © 2017 Magnolia Press Article PHYTOTAXA
ISSN 1179-3155 (print edition)
ISSN 1179-3163 (online edition)
Accepted by Genevieve Gates: 3 Mar. 2017; published: 21 Mar. 2017
https://doi.org/10.11646/phytotaxa.299.2.12
273
Hyphodontia zhixiangii sp. nov. (Schizoporaceae, Basidiomycota) from Uzbekistan
YU-HE KAN1,2, YUSUFJON GAFFOROV3, TONG LI1,2 & LI-WEI ZHOU1*
1CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang 110016, China
2University of Chinese Academy of Sciences, Beijing 100049, China
3Laboratory of Mycology, Institute of the Gene Pool of Plants and Animals, Academy of Sciences of the Republic of Uzbekistan, Tashkent
100053, Uzbekistan
*Corresponding author’s e-mail: liwei_zhou1982@163.com (LWZ)
Abstract
Hyphodontia zhixiangii is described as a new species from three Uzbek specimens recently collected on Juniperus. This spe-
cies is characterized by annual, resupinate basidiocarps with a grandinioid to odontioid hymenophore, a monomitic hyphal
system with clamp-connected generative hyphae, frequent lagenocystidia and subcapitate septocystidia, and ellipsoid to
broadly ellipsoid, thin-walled, smooth basidiospores measuring 4.6–5.5 × 3.3–4 μm. Morphologically, H. zhixiangii resem-
bles H. alutaria and H. arguta. H. alutaria differs mainly in its colliculose hymenophore and slightly smaller basidiospores
measuring 4.5–5 × 3–3.5 μm. H. arguta differs in the absence of septocystidia and bearing longer aculei measuring 0.5–2
µm in length. In the ITS-based phylogeny, H. zhixiangii nested within the Hyphodontia clade as a distinct lineage. Three
ITS sequences labeled as H. arguta did not cluster together. As it is not known if any of these sequences were obtained from
specimens collected in Sweden, the neotype locality, it is impossible to decide which one, if any, represents the genuine H.
arguta.
Key words: Central Asia, corticioid fungi, taxonomy, wood-inhabiting fungi
Introduction
Hyphodontia J. Erikss. (1958:101), with H. pallidula (Bres.) J. Erikss. (1958:104) as the generic type, was introduced
by Eriksson (1958). In the last monograph on this genus, 53 species were considered to be members of Hyphodontia
(Langer 1994). However, Hjortstam & Ryvarden (2009) applied a narrower concept of Hyphodontia after excluding
some species from this genus. Nine species are accepted in Hyphodontia, and as defined by Riebesehl et al. (2015),
this genus is morphologically characterized by resupinate basidiocarps, smooth to hydnoid or poroid hymenophores, a
monomitic to pseudodimitic hyphal system, generative hyphae with clamp connections, a presence of lagenocystidia
and sometimes capitate cystidia, and ellipsoid to ovoid, thin-walled, smooth basidiospores. The latest key to
Hyphodontia sensu lato indicates that the presence of lagenocystidia or short cylindrical cystidia apically encrusted
makes Hyphodontia distinct from other genera (Yurchenko & Wu 2016). Moreover, phylogeny inferred from the
ITS dataset also supported Hyphodontia as a distinct clade within Hyphodontia sensu lato (Yurchenko & Wu 2014,
Riebesehl et al. 2015).
It is well-known that specimens of wood-inhabiting fungi sharing quite similar morphological characters may
actually represent different species (Dai et al. 2014, Zhou et al. 2016). As a country in Central Asia connecting Europe
and East Asia, Uzbekistan possesses several biosphere reserves. The knowledge of wood-inhabiting fungi in Uzbekistan
might be helpful in understanding the speciation and diversification of fungi in Europe and East Asia. However, the
diversity of wood-inhabiting fungi in this country is still underexplored (Gafforov et al. 2014). To fill the gap, a 10-day
field trip surveying wood-inhabiting fungi was performed in September 2016. Three specimens collected in center-east
of Uzbekistan were identified as belonging to a new species of Hyphodontia, which is illustrated and described in the
present paper.

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274 • Phytotaxa 299 (2) © 2017 Magnolia Press
Materials and methods
Morphological studies:—The specimens studied are deposited in the herbarium of the Institute of Applied Ecology,
Chinese Academy of Sciences (IFP) and Mycological Herbarium, Uzbek Academy of Sciences (TASM). The
morphological procedure followed Pan & Zhou (2016). Macromorphology was observed from fresh and dry specimens
using a stereomicroscope. Special color terms followed Anonymous (1969) and Petersen (1996). Micromorphology
was examined from specimen sections, mounted in Cotton Blue (CB), Melzer’s reagent or 5% potassium hydroxide
(KOH), using a Nikon Eclipse 80i microscope at magnification up to × 1000. All sizes were measured from the sections
mounted with CB. When presenting the variation of basidiospore sizes, 5% of the measurements were excluded from
each end of the range and are given in parentheses. In the text, L stands for mean basidiospore length (arithmetic
average of all basidiospores), W for basidiospore width (arithmetic average of all basidiospores), Q for the range of
variation in the ratios of L/W between the specimens studied, and n for the number of basidiospores measured from a
given number of specimens. Drawings were made with the aid of a drawing tube.
DNA amplification and sequencing:—The Phire® Plant Direct PCR Kit (Finnzymes Oy, Finland) was used for
obtaining molecular sequences according to the manufacturer’s instructions. A small piece of dried specimen was
directly used as PCR template. Primers ITS5 and ITS4 (White et al. 1990) were selected for the amplification of ITS
region with the following procedure: initial denaturation at 98°C for 5 min, followed by 39 cycles at 98°C for 5 s, 59°C
for 5 s and 72°C for 5 s, and a final extension at 72°C for 10 min. The PCR products were sequenced with primers ITS5
and ITS4 at the Beijing Genomics Institute, China. The new ITS sequences were deposited in GenBank (http://www.
ncbi.nlm.nih.gov/genbank; Fig. 1).
Phylogenetic analysis:—To explore the phylogenetic affinity of the three Uzbek specimens, their ITS sequences
and additional ITS sequences of Hyphodontia sensu lato from previous studies (Yurchenko & Wu 2014; Zhao et al.
2014; Riebesehl et al. 2015; Chen et al. 2016) were incorporated. Fibrodontia gossypina Parmasto (1968:207) was
selected as the outgroup taxon (Yurchenko & Wu 2014). The ITS dataset was aligned using MAFFT 7.110 (Katoh &
Standley 2013) with default parameters but the G-INS-i opinion (Katoh et al. 2005). The best-fit evolutionary model of
the resulting alignment was estimated as GTR + I + G using jModelTest 2.1.4 (Guindon & Gascuel 2003, Darriba et al.
2012). Following this model, Maximum Likelihood (ML) and Bayesian Inference (BI) methods were selected to carry
out phylogenetic analysis. ML method was performed using raxmlGUI 1.2 (Stamatakis 2006, Silvestro & Michalak
2012) under the auto FC option (Pattengale et al. 2010) in bootstrap (BS) replicates. The BI method was performed
using MrBayes 3.2 (Ronquist & Huelsenbeck 2003) with two independent runs, each including four chains, starting
from random trees and executing 10 000 000 generations. Trees were sampled every 1 000th generation, and the first
quarter of sampling trees was removed as burn-in, whereas the others were used to construct a 50% majority consensus
tree and for calculating Bayesian posterior probabilities (BPPs). The convergence of chains was checked using Tracer
1.5 (http://tree.bio.ed.ac.uk/software/tracer/).
Results
Molecular phylogeny
The ITS dataset had 73 sequences and resulted in an alignment with 842 characters for phylogenetic analysis. The BS
search of this alignment in ML method stopped after 200 replicates. In BI method, all chains converged after 10 000
000 generations, indicated by the effective sample sizes of all parameters above 3 000 and the potential scale reduction
factors approaching 1.000. These two methods constructed congruent topologies, and thus only the topology generated
by ML method is presented. The statistical values are labeled at the nodes, if the BS values and the BPPs were greater
than 50% and 0.8, respectively. The phylogeny (Fig. 1) shows that the three newly sequenced Uzbek specimens formed
a distinct lineage with strong supports (99%/1) and fell into the fully supported Hyphodontia clade. This lineage was
closely related to the moderately supported (85%/0.92) lineage that is represented by two collections of Hyphodontia
arguta (Fr.) J. Erikss. (1958:104).

HYPHODONTIA ZHIXIANGII SP. NOV. Phytotaxa 299 (2) © 2017 Magnolia Press • 275
FIGURE 1. Phylogenetic position of Hyphodontia zhixiangii inferred from ITS dataset. The topology is generated by maximum likelihood
method. Bootstrap values and Bayesian posterior probabilities, if more than 50% and 0.8, respectively, are labeled at the nodes. The newly
sequenced specimens are in boldface.
Taxonomy
Hyphodontia zhixiangii L.W. Zhou & Yu.Sh. Gafforov, sp. nov. (Figs. 2, 3)
MycoBank MB 819659
Etymology:—Zhixiangii (Lat.): in memory of the corresponding author’s beloved father, Zhi-Xiang Zhou (周 智祥, December 1952–
November 2016), who was killed in a road traffic accident during the writing of the present paper.
Type:—UZBEKISTAN. Jizzakh Region, Zaamin District, Zaamin National Park, on the base of living Juniperus, 9 September 2016, LWZ
20160909-4 (holotype in IFP, isotype in TASM).
Description:—Basidiocarps annual, resupinate, inseparable from substrate, without odor or taste, soft corky when
fresh, brittle when dry, up to 15 cm long, 5 cm wide and 1 mm thick. Hymenophore grandinioid to odontioid. Aculei
cream to buff, subulate, 2–4 per mm, up to 0.8 mm long. Margin white, cottony, thinning, up to 1 mm wide. Subiculum
white to cream, up to 0.2 mm thick. Hyphal structure monomitic; generative hyphae with clamp connections; tissue
darkening but otherwise unchanged in KOH. Subiculum composed of generative hyphae, hyaline, slightly thick-
walled, frequently branched, loosely interwoven, cyanophilous, 2–3.5 μm in diam. Aculei tramal generative hyphae

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hyaline, slightly thick-walled, moderately branched, subparallel along the aculei, cyanophilous, 2–4 μm in diam.
Lagenocystidia frequent, hyaline, slightly thick- to thick-walled, 20–30 × 3–6 μm; subcapitate septocystidia frequent,
hyaline, thin- to thick-walled, with two or three septa, 35–70 × 4–6 μm. Basidia cylindrical to suburniform, thin-walled,
with four sterigmata and a clamp connection at base, 15–20 × 4–7 μm; basidioles similar in shape to basidia, but
smaller. Basidiospores ellipsoid to broadly ellipsoid, hyaline, thin-walled, smooth, mostly with a guttule, inamyloid,
non dextrinoid, acyanophilous, (4.3–)4.6–5.5(–6) × (3.2–)3.3–4(–4.3) μm, L = 5.04 μm, W = 3.75 μm, Q = 1.33–1.37
(n = 90/3).
Other specimens (paratypes) examined:—UZBEKISTAN. Jizzakh Region, Zaamin District, Zaamin National
Park, on stump of Juniperus, 9 September 2016, LWZ 20160909-8 (IFP, a duplicate in TASM), LWZ 20160909-9 (IFP,
a duplicate in TASM).
FIGURE 2. Basidiocarps of Hyphodontia zhixiangii (holotype). Bar = 1 cm. Photo by Li-Wei Zhou.
Discussion
Hyphodontia zhixiangii is characterized by annual, resupinate basidiocarps with a grandinioid to odontioid hymenophore,
a monomitic hyphal system with clamp-connected generative hyphae, frequent lagenocystidia and subcapitate
septocystidia, and ellipsoid to broadly ellipsoid, thin-walled, smooth basidiospores measuring 4.6–5.5 × 3.3–4 μm.
These characters indicate H. zhixiangii belongs to Hyphodontia sensu Riebesehl et al. (2015). The phylogeny inferred
from ITS dataset also indicates that H. zhixiangii is in the Hyphodontia clade (Fig. 1).
Hyphodontia zhixiangii resembles H. alutaria (Burt) J. Erikss. (1958:104) in the cream to buff basidiocarps,
cyanophilous generative hyphae, frequent presence of lagenocystidia and subcapitate septocystidia (Eriksson & Ryvarden
1976). These characters make them distinct from other species of Hyphodontia (Yurchenko & Wu 2016). Hyphodontia
alutaria differs from H. zhixiangii mainly in its colliculose hymenophore and slightly smaller basidiospores measuring
4.5–5 × 3–3.5 μm (Eriksson & Ryvarden 1976). Hyphodontia alutaria was originally collected from Vermont, USA
(Burt 1925) and is considered to be a cosmopolitan species (Yurchenko & Wu 2016). However, we failed to find an
examination of specimens of H. alutaria from Central Asia in any well-known monograph or paper. Moreover, the
current ITS-based phylogeny clearly separated H. zhixiangii from two Nordic specimens of H. alutaria (Fig. 1).
Three ITS sequences of Hyphodontia arguta have been used in recent phylogenetic analyses (Yurchenko & Wu
2014, Riebesehl et al. 2015). Phylogenetically, all of them nested within the Hyphodontia clade, but did not cluster
together (Fig. 1). Two of them formed a moderately supported lineage and had a close relationship with H. zhixiangii,
while the third one represented a distinct lineage (Fig. 1). These three sequences were obtained from specimens
collected outside of Sweden, where the neotype of H. arguta was selected (Langer 1994). Therefore, it is impossible to
decide which one, if any, represents the genuine H. arguta before further morphological examinations, which is beyond
the scope of the present paper. Morphologically, H. arguta does not bear septocystidia (Eriksson & Ryvarden 1976,
Langer 1994), which makes it distinct from H. zhixiangii. In addition, H. arguta has longer aculei measuring 0.5–2
µm in length (Eriksson & Ryvarden 1976). The presence of septa in septocystidia might be overlooked, especially
in immature specimens; therefore certain Central Asian specimens of H. arguta deposited in herbaria might actually

HYPHODONTIA ZHIXIANGII SP. NOV. Phytotaxa 299 (2) © 2017 Magnolia Press • 277
represent H. zhixiangii. Future studies on global samples labeled as H. arguta, especially those from Sweden, will help
reveal the real diversity of this species group.
The main morphological differences among Hyphodontia alutaria, H. arguta and H. zhixiangii are compared in
Table 1.
We conclude that Hyphodontia zhixiangii is a new species of Hyphodontia based on the morphological and
phylogenetic evidence presented.
FIGURE 3. Microscopic structures of Hyphodontia zhixiangii (holotype). a: Basidiospores. b: Basidia and basidioles. c: Lagenocystidia.
d: Subcapitate septocystidia. e: Hyphae from trama. f: Hyphae from subiculum. Bar = 10 μm. Drawings by Li-Wei Zhou.

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TABLE 1. Morphological comparison of Hyphodontia alutaria, H. arguta and H. zhixiangii based on Eriksson & Ryvarden
(1976), Langer (1994) and the present study.
Species Hymenophore Septocystidia Basidiospores (L × W, µm)
H. alutaria Colliculose 0–3 septa 4.5–5 × 3–3.5
H. arguta Odontioid (0.5–2 mm) 0-septate 4.5–6 × 3.5–4
H. zhixiangii Grandinioid to odontioid (up to 0.8 mm) 2–3 septa 4.6–5.5 × 3.3–4
Acknowledgements
The research was financed by the National Natural Science Foundation of China (Project No. 31570014) and Youth
Innovation Promotion Association CAS (No. 2017240). Dr. Yusufjon Gafforov acknowledges the Committee for
coordination science and technology development under the Cabinet of Ministers of Uzbekistan for financial support
of research project (#P3-2014-0830174425).
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