Serpula dendrocalami C.L. Zhao, 2019

Wang, Xiang-Hua, Das, Kanad, Bera, Ishika, Chen, Yu-Hui, Bhatt, Rajendra Prasad, Ghosh, Aniket, Hembrom, Manoj Emanuel, Hofstetter, Valérie, Parihar, Arvind, Vizzini, Alfredo, Xu, Tai-Min & Zhao, Chang-Lin, 2019, Fungal Biodiversity Profiles 81 - 90, Cryptogamie, Mycologie 20 (5), pp. 57-95 : 88-94

90. Serpula dendrocalami C.L. Zhao , sp. nov.

( Figs 22-26 )

Differs from other Serpula species by the larger, pileate basidiocarps with poroid hymenophore and a dimitic hyphal system with wider, encrusted generative hyphae in context (3-6.5 Μm) and subglobose, bright yellow, thick-walled basidiospores measuring as 4.5-5.5´3.5-4 Μm.

TYPUS. — China. Yunnan Prov., Puer, Taiyanghe Forestry Park , on root of the living bamboo of Dendrocalamus , 30.IX.2017, C.L. Zhao, Zhao 3321 ( SWFC) .

MYCOBANK. — MB 830774.

GENBANK. — MK863397 - MK863407 (ITS); MK863391 - MK863396 (LSU).

ETYMOLOGY. — dendrocalami (Lat.) . — referring to the host, the bamboo genus Dendrocalamus .

ADDITIONAL SPECIMENS EXAMINED. — China. Yunnan Prov.: Puer, Taiyanghe Forestry Park, on root of living bamboo of Dendrocalamus , 30.IX.2017, C.L. Zhao, Zhao 3111, 3113, 3136, 3203, 3318, 3447, 4805; Jingdong Co., Wuliangshan National Nature Reserve, on root of living bamboo of Dendrocalamus , 2.X.2017, C.L. Zhao, Zhao 3521, 3607, 3626, 3632 (SWFC).

DESCRIPTION

Basidiocarps

Annual, pileate, solitary or gregarious, fleshy and more or less watery when fresh, becoming corky and brittle upon drying, distinctly light in weight when dry.

Pileus

Sessile, flabelliform to semicircular, projecting up to 20 cm, 15 cm wide, 2.5 cm thick at centre. Pileal surface cream to pale brown when fresh and brown upon drying, smooth, and uneven.

Hymenial surface

Poroid, slightly meruloid towards margin, yellowish brown when fresh, yellowish brown to brown, paler towards margin, darker towards centre upon drying; pores angular, 2-3/mm; dissepiments thin. Sterile margin wide, cream to yellowish brown, up to 5 mm wide.

Context

Cream, spongy, up to 2 cm thick.

Tubes

Yellowish brown to brown, up to 5 mm long.

Type of rot

Brown rot.

Hyphal system

Dimitic; generative hyphae with clamp connections, IKI-, CB-, tissues unchanged in KOH.

Context

Generative hyphae dominant, hyaline, thin-walled, occasionally branched, interwoven, 3-6.5 Μm in diameter, frequently encrusted with crystals; skeletal hyphae hyaline, thick-walled with a lumen, branched, 0.8-3 Μm in diam.

Tubes

Generative hyphae hyaline, thin-walled, occasionally branched, interwoven, 2.5-5 Μm in diameter, frequently encrusted with crystals; skeletal hyphae absent. Cystidia and cystidioles absent. Basidia clavate to pyriform, with four sterigmata and a basal clamp connection, 25-35 × 7-8.5 Μm; basidioles in shape similar to basidia, but slightly smaller.

Basidiospores

Subglobose, bright yellow, thick-walled, smooth, IKI-, cyanophilous, (4-)4.5-5.5(-6) × 3.5-4(-4.5) Μm, L = 5.13 Μm, W = 3.83 Μm, Q = 1.26-1.42 (n = 360/12).

NOTES

Wood-rotting fungi is an extensively studied group of Basidiomycota ( Gilbertson & Ryvarden 1987; Núñez & Ryvarden 2001; Bernicchia & Gorjón 2010; Dai 2012; Ryvarden & Melo 2014), but the Chinese wood-rotting fungi diversity is still not well known. This is especially the case for the subtropical and tropical zones, from which many recently described taxa of wood-rotting fungi were described ( Chen & Shen 2014; Zhao et al. 2014; Zhou 2015; Qin et al. 2016; Song et al. 2016).

Serpula (Pers.) Gray ( Serpulaceae , Boletales ) is a genus typified by S.lacrymans (Wulfen)J.Schröt ( Gray 1821) , which is a small genus characterized by a combination of resupinate to effuse-reflexed, or pileate basidiocarps mostly with merulioid to poroid hymenophore, a dimitic hyphal system with clamp connections on generative hyphae,presence of skeletal hyphae in the context, clavate basidia and ellipsoid to ovoid, smooth, thick-walled, brownish, not or weakly dextrinoid, cyanophilous basidiospores, and all causing a brown rot ( Gray 1821; Bernicchia & Gorjón 2010). So far about 17species have been accepted in the genus worldwide ( Gray1821; Karsten1884; Schröter 1888; Cooke 1957; Ginns 1971; Mata & Ryvarden 2007; Bernicchia & Gorjón 2010).

Recently, several molecular studies addressed the genus Serpula ( Binder & Hibbett 2006; Larsson 2007; Binder et al. 2010; Zhao et al. 2017). Binder & Hibbett (2006) suggested that the genus Serpula clustered into the Serpulaceae in Boletales where it grouped with Coniophora marmorata Desm. and Tapinella atrotomentosa (Batsch) Šutara. Larsson (2007) introduced a phylogenetic classification for corticioid fungi at the family level confirming that the genus Serpula was nested into the Boletales clade where it grouped with Coniophora olivacea (Fr.) P. Karst. and Pseudomerulius aureus (Fr.) Jülich. A few years later, Binder et al. (2010) included five species of Serpula in a study focusing on early branching clades in Agaricomycetidae . Again, these Serpula clustered with Leucogyrophana montana (Burt) Domański and T. atrotomentosa in the order Boletales . In their six-gene phylogenetic overview of Basidiomycota, Zhao et al. (2017) demonstrated that the type species of Serpula , S. lacrymans , clustered with Coniophora arida (Fr.) P. Karst. and Gyrodontium sacchari (Spreng.) Hjortstam in the Boletales .

In our phylogenetic analyses ( Figs. 19-21 ), Serpula dendrocalami sisters to S. similis in the phylogeny with strong supports (100% BS, 100% BP, 1.00 BPP,) but the latter differs from S.dendrocalami by its smaller basidiocarps projecting up to 3 cm, 5 cm wide, 5 mm thick at centre ( Dai 2004) with pruinose or tomentose margin, the meruloid folded hymenium, and 1 mm thin context with numerous crystals that are not incrusting the hyphae, and smaller basidiospores measuring 4-5 × 3-3.5 Μm ( Ginns 1971). In addition, its habitat is linked to sandy soil.

Two other species in the genus Serpula from China are similar to the new taxon: S. himantioides (Fr.) P. Karst. and S. lacrymans (Wulfen) J. Schröt. The former differs from S. dendrocalami by the membranaceous basidiocarps with smooth hymenophore and larger basidiospores, 9-12 × 5-6 Μm ( Bernicchia & Gorjón 2010), and grows on stumps of Picea or Pinus . Serpula lacrymans is separated from S. dendrocalami by its resupinate to effuse-reflexed basidiocarps with rhizomorphs, and larger basidiospores, 9-10.1 × 4.6-5.9 Μm( Dai 2004, Bernicchia & Gorjón 2010) and grows on manufactured wood such as in old woody houses.

Figures

FIG. 22. — Maximum parsimony strict consensus tree illustrating the phylogeny of Serpula dendrocalami C.L. Zhao,sp. nov.,and related species in Serpula based on ITS sequences. Branches are labeled with parsimony bootstrap values (before slash) higher than 50% and Bayesian posterior probabilities (after slash) equal to and more than 0.95. The ITS dataset included sequences from 22 fungal specimens representing 8 taxa. The dataset had an aligned length of 905 characters in the dataset, of which 441 characters are constant, 163 are variable and parsimony-uninformative, and 301 are parsimony-informative. Maximum parsimony analysis yielded 1 equally parsimonious tree (TL = 795, CI = 0.815, HI = 0.185,RI = 0.897, RC = 0.731). Best model for ITS estimated and applied in the Bayesian analysis: GTR+I+G, lset nst = 6, rates = invgamma; prset statefreqpr = dirichlet (1,1,1,1). Bayesian analysis resulted in the same topology with an average standard deviation of split frequencies = 0.001810. Sampled specimens of the new species, Serpula dendrocalami sp. nov., formed a well-supported monophyletic lineage. The EZNA HP Fungal DNA Kit (Omega Biotechnologies Co., Ltd, Kunming) was used to obtain PCR products from dried specimens, according to the manufacturer’s instructions with some modifications. ITS region was amplified with primer pairs ITS5 and ITS4 (White et al. 1990). The PCR procedure for ITS was as follows: initial denaturation at 95 °C for 3 min, followed by 35 cycles at 94 °C for 40 s, 58 °C for 45 s and 72 °C for 1 min, and a final extension of 72 °C for 10 min. The PCR products were purified and directly sequenced at Kunming Tsingke Biological Technology Limited Company.All newly generated sequences were deposited at GenBank (Table 1). Branches are lab eled with parsimony bootstrap values (before slash) higher than 50% and Bayesian posterior probabilities (after slash) equal to and more than 0.95.

FIG. 23. — Maximum parsimony Strict consensus tree illustrating the phylogeny of Serpula dendrocalami C.L. Zhao,sp. nov.,and related species in Serpula based on nLSU sequences. Branches are labeled with parsimony bootstrap values (before slash) higher than 50% and Bayesian posterior probabilities (after slash) equal to and more than 0.95. The nLSU dataset included sequences from 16 fungal specimens representing 8 species. The dataset had an aligned length of 1411 characters,of which 1158 characters are constant, 69 are variable and parsimony-uninformative, and 184 are parsimony-informative. Maximum parsimony analysis yielded 4 equally parsimonious trees (TL = 321, CI = 0.854, HI = 0.146, RI = 0.947, RC = 0.808). Best model for the nLSU dataset estimated and applied in the Bayesian analysis: GTR+I+G, lset nst = 6, rates = invgamma; prset statefreqpr = dirichlet (1,1,1,1). Bayesian analysis and ML analysis resulted in a similar topology as MP analysis, with an average standard deviation of split frequencies = 0.003841 (BI). This phylogenetic analysis demonstrated that our species was closely related to S. similis (Berk. & Broome) Ginns. Nuclear LSU region was amplified with primer pairs LR0R and LR7 (http://www.biology.duke.edu/fungi/mycolab/primers.htm). The PCR procedure for nLSU was as follows: initial denaturation at 94 °C for 1 min, followed by 35 cycles at 94 °C for 30 s, 48 °C 1 min and 72 °C for 1.5 min, and a final extension of 72 °C for 10 min. The PCR products were purified and directly sequenced at Kunming Tsingke Biological Technology Limited Company. All newly generated sequences were deposited at GenBank (Table 1). Branches are labeled with parsimony bootstrap values (before slash) higher than 50% and Bayesian posterior probabilities (after slash) equal to and more than 0.95.

FIG. 24. — Maximum parsimony Strict consensus tree illustrating the phylogeny of Serpula dendrocalami C.L. Zhao,sp. nov.,and related species in Serpula based on combined ITS+nLSU sequences. Branches are labeled with parsimony bootstrap values (before slash) higher than 50% and Bayesian posterior probabilities (after slash) equal to and more than 0.95. This phylogenetic analysis shows that our new species formed a monophyletic entity with high support, 100% BS, 100% BP and 1.00 BPP,and grouped with S. similis. Sequences from 14 fungal specimens representing 8 species are included. The dataset had an aligned length of 2389 characters, of which 1638 characters are constant, 271 are variable and parsimony-uninformative, and 480 are parsimony-informative. Maximum parsimony analysis yielded 4 equally parsimonious trees (TL = 1144, CI = 0.832, HI = 0.168, RI = 0.891, RC = 0.741). Best model for the ITS+nLSU dataset estimated and applied in the Bayesian analysis: GTR+I+G, lset nst = 6, rates = invgamma; prset statefreqpr = dirichlet (1,1,1,1). Bayesian analysis and ML analysis resulted in a similar topology as MP analysis, with an average standard deviation of split frequencies = 0.001815 (BI). Branches are labeled with parsimony bootstrap values (before slash) higher than 50% and Bayesian posterior probabilities (after slash) equal to and more than 0.95.

FIG. 25. — Serpula dendrocalami C.L. Zhao, sp. nov. (holotype): basidiocarps. Scale bars: A, 5 cm; B, 4 cm.

FIG. 26. — Serpula dendrocalami C.L. Zhao, sp. nov. (holotype), microscopic structures: A, basidiospores; B, basidia and basidioles; C, a section of hymenium; D, hyphae from trama; E, hyphae from context; F, skeletal hyphae from context. Scale bars: A, 5 µm; B-F, 10 µm.

FIG. 19. — Phylogram generated from Maximum Likelihood approach (ML) in raxmlGUI 1.2 (Stamatakis et al.2008; Silvestro & Michalak 2012) with 1000 bootstrap replicates. One thousand bootstrap replicates were analyzed to obtain the nodal support values. Bootstrap support values (>70%) are shown above or below the branches at nodes. The Indian specimens of Russula clavatohyphata R.P. Bhatt, A. Ghosh, Buyck & K. Das, sp. nov., with GenBank Accession Numbers are shown in bold red.

FIG. 20. — Russula clavatohyphata R.P. Bhatt, A. Ghosh, Buyck & K. Das, sp. nov. (AG 15-756): A-D, fresh and sectioned basidiomata in the field and basecamp; E-G, radial section through pileipellis showing elements; H-K, transverse section through lamellae showing pleurocystidia; L, SEM micrograph of basidiospores. Scale bars: A, 50 mm; E-K, 10 µm; L, 3 µm.

FIG. 21. — Russula clavatohyphata R.P. Bhatt, A. Ghosh, Buyck & K. Das, sp. nov. (AG 15-756): A, sectioned basidiome; B, basidiospores; C, hyphal extremities at the pileus surface; D, pleurocystidia; E, cheilocystidia; F,basidia. Scale bars: A, 10 mm; B-F, 10 µm.