New corticioid taxa in Phanerochaetaceae (Polyporales, Basidiomycota) from East Asia

The species diversity, taxonomy, and phylogeny of five corticioid genera of Phanerochaetaceae, namely, Hyphodermella, Roseograndinia, Phlebiopsis, Rhizochaete, and Phanerochaete, in East Asia are studied by using the morphological and molecular methods. Phylogenetic analyses were performed separately for the Donkia, Phlebiopsis, Rhizochaete, and Phanerochaete clades based on ITS1-5.8S-ITS2 and nrLSU sequence data. In total, seven new species were found, two new combinations are suggested, and a new name is proposed. In the Donkia clade, Hyphodermella sensu stricto was strongly supported with two new lineages, namely H. laevigata and H. tropica, which were recovered. Hyphodermella aurantiaca and H. zixishanensis are members of Roseograndinia, while R. jilinensis is proved to be a later synonym of H. aurantiaca. In the Phlebiopsis clade, P. cana sp. nov. was found on the bamboo from tropical Asia. In the Rhizochaete clade, four new species, R. nakasoneae, R. subradicata, R. terrestris, and R. yunnanensis were recovered based mainly on molecular analyses. In the Phanerochaete clade, P. subsanguinea nom. nov. is proposed to replace Phanerochaete rhizomorpha C.L. Zhao & D.Q. Wang, which is an invalid name because it was published after Phanerochaete rhizomorpha C.C. Chen, Sheng H. Wu & S.H. He, representing another species. Descriptions and illustrations are provided for the new species, and discussions are given for new taxa and names. Identification keys to Hyphodermella species worldwide and Rhizochaete species in China are given separately.


Introduction
The species diversity, taxonomy, and phylogeny of the large phlebioid clade, which includes three families, namely, Phanerochaetaceae, Irpicaceae and Meruliaceae, have been intensively studied in recent years, and the number of taxa has been dramatically increased (Floudas and Hibbett, 2015;Miettinen et al., 2016;Justo et al., 2017;Nakasone et al., 2017Nakasone et al., , 2021Chen et al., 2018bChen et al., , 2020Chen et al., , 2021Chen et al., , 2022Ma and Zhao, 2019;Huang and Zhao, 2020;Gu and Zhao, 2021;Zhao et al., 2021;Li et al., 2022). To date, 60 genera of poroid, corticioid, and hydnoid fungi are recognized in the three families, which mostly cause white rot on both angiosperms and gymnosperms Nakasone et al., 2021;Lira et al., 2022). Among corticioid fungi, Phanerochaete s.l. and Phlebia s.l. are the two largest groups in the clade, which have been divided into many small genera with the aid of molecular systematics.
East Asia, especially the tropic areas, has been shown to be rich in the species diversity of the corticioid fungi of the phlebioid clade Huang and Zhao, 2020;Chen et al., 2021;Gu and Zhao, 2021;Li et al., 2021Li et al., , 2022Zhao et al., 2021). Although many new taxa were described from this region, the species diversity, especially for the cryptic species, has not been completely understood, and the generic positions of some species need to be further studied . In this study, we carried out complete taxonomic and phylogenetic studies on the newly collected specimens and some newly described taxa of corticioid fungi in Phanerochaetaceae from East Asia. Seven new species in Hyphodermella, Phlebiopsis, and Rhizochaete were found, and two new combinations of Roseograndinia and a new name for Phanerochaete are proposed. These results are continuations and supplements to the research of phlebioid fungi in China.

Specimen collection
Field trips for specimen collection in several nature reserves and forest parks in China and other countries were carried out by the authors. In situ photos of the fungi were taken with a Canon EOS 70D camera (Canon Corporation, Japan). Fresh specimens were dried at 40 • C with a portable drier (manufactured in Finland). Dried specimens were labeled and then stored in a refrigerator at −40 • C for 2 weeks to kill the insects and their eggs before they were ready for morphological and molecular studies. Voucher specimens are deposited at the herbaria of Beijing Forestry University, Beijing, China (BJFC), the National Museum of Natural Science, Taichung, Taiwan (TNM), and the Center for Forest Mycology Research, Madison, Wisconsin, U. S.A. (CFMR). Herbarium code designations follow the Index Herbariorum.

Morphological studies
Thin, freehand sections were made from dried basidiomes and mounted in 2% (w/v) aqueous potassium hydroxide (KOH) and 1% (w/v) aqueous phloxine. Amyloidity and dextrinoidity of basidiospores were checked in Melzer's reagent (IKI). Cyanophily of hyphal and basidiospore walls was observed in 1% (weight/volume) cotton blue in 60% (w/v) lactic acid (CB). Microscopic examinations were carried out with a Nikon Eclipse 80i microscope (Nikon Corporation, Japan) at magnifications up http://sweetgum.nybg.org/science/ih/ to 1,000×. Drawings were made with the aid of a drawing tube. The following abbreviations are used: IKI-= neither amyloid nor dextrinoid, CB-= acyanophilous, L = mean spore length, W = mean spore width, Q = L/W ratio, and n (a/b) = the number of spores (a) measured from the number of specimens (b). Color codes and names were followed as suggested by Kornerup and Wanscher (1978).

DNA extraction and sequencing
A CTAB plant genomic DNA extraction kit, DN14 (Aidlab Biotechnologies Co., Ltd, Beijing, China), was used to extract total genomic DNA from dried specimens, which was then amplified by the polymerase chain reaction (PCR), according to the manufacturer's instructions. The ITS1-5.8S-ITS2 region (ITS) was amplified with the primer pair ITS5/ITS4 (White et al., 1990) using the following protocol: initial denaturation at 95 • C for 4 min, followed by 34 cycles at 94 • C for 40 s, 58 • C for 45 s, 72 • C for 1 min, and the final extension at 72 • C for 10 min. The nrLSU D1-D2 region (nrLSU) was amplified with the primer pair LR0R/LR7 using the following procedure: initial denaturation at 94 • C for 1 min, followed by 34 cycles at 94 • C for 30 s, 50 • C for 1 min, 72 • C for 1.5 min, and the final extension at 72 • C for 10 min. DNA sequencing was performed at the Beijing Genomics Institute, and the sequences were deposited in GenBank (Table 1). BioEdit v. 7.0.5.3 (Hall, 1999) and Geneious Basic v.11. 1.15 (Kearse et al., 2012) were used to review the chromatograms and for contig assembly.

Phylogenetic analyses
Four separate datasets of concatenated ITS-nrLSU sequences of the Donkia, Phlebiopsis, Rhizochaete, and Phanerochaete clades in the Phanerochaeteaceae were analyzed. The clades recognition and ingroup and outgroup taxa selections were mainly discussed in the study by Chen et al. (2021). The Phanerochaete clade included only taxa in the core group of the genus. Rhizochaete radicata (Henn.) Gresl., Nakasone & Rajchenb. was selected as the outgroup for the Donkia and Phlebiopsis clades, while Phlebiopsis gigantea (Fr.) Jülich was used as the outgroup for the Rhizochaete and Phanerochaete clades. The ITS and nrLSU sequences were aligned separately using MAFFT v.7 (Katoh et al., 2017) with the G-INS-I iterative refinement algorithm and optimized manually in BioEdit v. 7.0.5.3. Then, the separate alignments were concatenated using Mesquite v. 3.5.1 (Maddison and Maddison, 2018).
/fmicb. .    New taxa are set in bold with type specimens indicated with an asterisk ( * ).
Frontiers in Microbiology frontiersin.org . /fmicb. . (TBR) branch-swapping algorithm with all characters given equal weight. Branch supports for all parsimony analyses were estimated by performing 1,000 bootstrap replicates with a heuristic search of 10 random-addition replicates for each bootstrap replicate. In ML analysis, statistical support values were obtained using rapid bootstrapping with 1,000 replicates, with default settings for other parameters. For BI, the best-fit substitution model was estimated with jModeltest v. 2.17 (Darriba et al., 2012). Four Markov chains were run for 1,000,000 for the three datasets of the Donkia, Phanerochaete, and Phlebiopsis clades and the 2,000,000 for the dataset of the Rhizochaete clade until the split deviation frequency value was lower than 0.01. Trees were sampled every 100th generation. The first quarter of the trees, which represented the burn-in phase of the analyses, were discarded, and the remaining . /fmicb. . trees were used to calculate posterior probabilities (BPP) in the majority rule consensus tree.

Phylogenetic analyses
The dataset of the Donkia clade contained 39 ITS and 38 nrLSU sequences from 39 samples, representing 19 ingroup taxa and the outgroup (Table 1)     MycoBank: MB846336 Diagnosis-The species is recognized by a smooth hymenophore, the absence of cystidia and cystidioid hyphal ends, and small ellipsoid basidiospores.
Etymology-Refer to the smooth hymenophore.
/fmicb. . Notes-Hyphodermella tropica ( Figure 6) is characterized by coriaceous basidiomes with a grandinioid hymenophore, the presence of encrusted cystidioid hyphal ends, and broadly ellipsoid to ovoid basidiospores. In the phylogenetic tree (Figure 1), H. tropica formed a distinct lineage sister to H. pallidostraminea Bukharova & Volobuev and H. laevigata. Hyphodermella pallidostraminea from Russia differs from H. tropica by having a smooth to slightly tuberculate hymenophore, not encrusted cystidioid hyphal ends in hymenium, and narrower ellipsoid basidiospores (3-3.5 µm, Crous et al., 2021). Hyphodermella laevigata can be easily distinguished from H. tropica by the smooth hymenophore, the loose texture of the subiculum, and the lack of encrusted cystidioid hyphal ends. Hyphodermella brunneocontexta Duhem & Buyck from France is similar to H. tropica by sharing an odontioid hymenophore, encrusted cystidioid hyphal ends, and ellipsoid to ovoid basidiospores but differs in having a brown context with densely interwoven hyphae (Duhem and Buyck, 2011).  = Roseograndinia jilinensis C. C. Chen & Sheng H. Wu, Fungal Diversity 111: 396, 2021. [MB#840765] Notes-Both H. aurantiaca and R. jilinensis were recently described from China, and are similar to each other by sharing a smooth to tuberculate, reddish hymenophore, a compact context with a thickened subhymenium, the absence of cystidia, and relatively small ellipsoid basidiospores but differ in the size of the basidiospores according to the descriptions (3-4 × 2-2.8 µm of H. aurantiaca vs. 4.6-5.5 × 2.6-3.1 µm of R. jilinensis, Wang and Zhao, 2020;Chen et al., 2021). However, in our phylogenetic tree (Figure 1), the types of the two species clustered in a strongly supported lineage in the Roseograndinia clade (99/93/1) with the ITS sequence similarity reaching 99.5% (3 differences of 600 base pairs). Thus, based on the morphological and molecular evidence, the new combination R. aurantiaca is proposed herein, since the epithet "aurantiaca" has the priority. Notes-The species H. zixishanensis was recently described from Yunnan Province, southwestern China, based on morphological and molecular evidence . In our phylogenetic tree based on a more complete sampling, including many newly described taxa (Figure 1), the species was nested within the Roseograndinia clade, which was strongly supported as a monophyletic clade with three species and  independent of Hyphodermella. Morphologically, Roseograndinia zixishanensis has the typical characteristics of the genus by possessing ceraceous basidiomes with a smooth to tuberculate hymenophore, a monomitic hyphal system with simple-septate generative hyphae, and a lack of cystidia .

Phlebiopsis cana Yue Li & S.H. He, sp. nov.
MycoBank: MB846340 Diagnosis-The species is recognized by a smooth hymenophore with a gray to brownish gray hymenial surface, the presence of short lamprocystidia and short cylindrical basidiospores, and its growth on bamboo.
Etymology-Refer to the gray color of basidiomes.
Fruiting body-Basidiomes annual, resupinate, widely effused, closely adnate, inseparable from the substrate, and coriaceous, first as small patches and later confluent up to 11 cm long, 2 cm wide, and up to 40 µm thick in section. Hymenophore smooth, gray (4C1) to brownish gray (4D2), slightly darkening in KOH, and not cracked upon drying; the margin thinning out, adnate, indistinct, and concolorous with hymenophore surface when juvenile, and darkening with age; and context is gray.
Notes-Phlebiopsis cana (Figure 7) is characterized by having thin basidiomes with a gray, smooth hymenophore surface, short lamprocystidia, and cylindrical basidiospores. In the phylogenetic tree ( Figure 2), P. cana formed a lineage sister to P. xuefengensis J. Zou, which is an endophyte of Gastrodia elata from China. The descriptions of P. xuefengensis were based on cultures and not standard or comparable with P. cana (Li et al., 2021). Phlebiopsis cylindrospora Y. N. Zhao & S.H. He that was also found on bamboos in China is similar to P. cana by sharing short lamprocystidia and cylindrical basidiospores but differs in having hymenophores turning purple in KOH, generative hyphae encrusted with yellow, resinous granules, and slightly larger basidiospores (5.5-7.5 × 1.8-2.8 µm, Zhao et al., 2021). Another Phlebiopsis species on bamboo from Taiwan, P. yushaniae C.C. Chen & Sheng H. Wu, differs from P. cana by possessing white to cream basidiomes, possessing broadly ellipsoid to subglobose basidiospores (6.9-7.9 MycoBank: MB846341 Diagnosis-The species is recognized by a smooth hymenophore turning pinkish buff in KOH, the presence of thick-walled lamprocystidia, and broadly ellipsoid to ovoid basidiospores. Type-China, Hunan Province, Zhangjiajie, Zhangjiajie Forest Park, on a fallen angiosperm trunk, 7 July 2015, He 2291 (BJFC 020746, holotype).
Etymology-Named to honor Dr. Karen K. Nakasone (CFMR, USA), who contributed much to the taxonomy and phylogeny of Rhizochaete. Fruiting body-Basidiomes annual, resupinate, widely effused, loosely adnate, easily separated from substrate, and membranaceous to pellicular, first as small patches, later confluent up to 4 cm long, 2 cm wide, and up to 120 µm thick in section. Hymenophore smooth, light orange (6A5) to grayish orange (5B5), turning pinkish buff in KOH, not cracked upon drying; the margin thinning out, adnate, fimbriate, sterile, white when fresh, .
/fmicb. . and becoming pale yellow upon drying; hyphal cords are present, brownish yellow, and turning pinkish buff in KOH; and context is pale yellow.
Etymology-Refer to the morphological similarity and close phylogenetic relationship of R. radicata.
Fruiting body-Basidiomes annual, resupinate, widely effused, loosely adnate, easily separated from substrate, and membranaceous to pellicular, first as small patches, later confluent up to 6 cm long, 3 cm wide, and up to 200 µm thick in section. Hymenophore smooth,light orange (5A5) to grayish orange (5B5), turning reddish brown in KOH, and not cracked upon drying; the margin thinning out, adnate, fimbriate, sterile, white or pale orange when juvenile, and slightly darkening with age; hyphal cords present, brownish yellow, and turning reddish brown in KOH; and context is pale yellow.

Rhizochaete yunnanensis
Fruiting body-Basidiomes annual, resupinate, widely effused, loosely adnate, easily separated from the substrate, and membranaceous to pellicular, first as small patches, later confluent up to 5 cm long, 2 cm wide, and up to 160 µm thick in section. Hymenophore smooth, grayish yellow (4B4) to brownish orange (5B6), turning reddish brown in KOH, and not cracked upon drying; the margin thinning out, adnate, fimbriate, paler than hymenophore surface, and cream; hyphal cords yellow and turning reddish brown in KOH; and context is yellow.
Description-See   . Our morphological and phylogenetic studies on the representative specimens showed that the two names represented two distinct species (Figure 4). Therefore, we propose the new name P. subsanguinea (Figure 13) to replace P. rhizomorpha C.L. Zhao & D.Q. Wang.

Discussion
The phylogeny of the Phanerochaetaceae at the generic level is becoming much clearer with some new genera introduced for the independent lineages (Floudas and Hibbett, 2015;Miettinen et al., 2016;Yuan et al., 2017;Chen et al., 2018bChen et al., , 2021Ma and Zhao, 2019). At present, the family includes 23 genera, most of which are corticioid fungi . Although most of the newly described taxa in the family originated from East Asia, some groups in this area still need more systematic studies based on more complete samplings. Chen et al. (2021) used Roseograndinia for a distinct lineage of two new species, which are morphologically similar to the type, R. rosea (Henn.) Hjortstam & Ryvarden. Morphologically, the genus is similar to Hyphodermella, which differs by having encrusted cystidioid hyphal ends. Our phylogenetic analyses based on more samples of the two genera showed that two recently described species without cystidioid hyphal ends, Hyphodermella aurantica and H. zixishanensis, nested within the Roseograndinia. Meanwhile, two new species, H. laevigata and H. tropica, in the core clade of Hyphodermella were found, though the former species also lacks cystidioid hyphal ends. The poroid species, Hyphodermella poroides Y.C. Dai & C.L. Zhao, did not nest within the core group of the genus but clustered with Geliporus exilisporus (Y.C. Dai & Niemelä) Yuan, Jia J. Chen & S.H. He. However, their relationship was not well supported, and there are clear morphological differences between the two species (Yuan et al., 2017;Zhao et al., 2017). At present, we accept a broad concept of Hyphodermella to include nine species as follows: .

Author contributions
YL performed the phylogenetic analyses and did most of the measurements, descriptions, and illustrations. C-CC provided some specimens and sequences and revised the manuscript. S-HH designed the research, collected most of the specimens, and wrote and revised the manuscript. All authors contributed to the article and approved the submitted version.

Funding
Financial support was provided by the National Natural Science Foundation of China (Nos. 31870011 and 31750001).