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Research Article
New species of Tropicoporus (Basidiomycota, Hymenochaetales, Hymenochaetaceae) from India, with a key to Afro-Asian Tropicoporus species
expand article infoSugantha Gunaseelan‡, Kezhocuyi Kezo‡, Samantha C. Karunarathna§|, Erfu Yang§, Changlin Zhao#, Abdallah M. Elgorban¤, Saowaluck Tibpromma§, Malarvizhi Kaliyaperumal‡
‡ University of Madras, Chennai, India
§ Qujing Normal University, Yunnan, China
| National Institute of Fundamental Studies (NIFS), Kandy, Sri Lanka
¶ Chiang Mai University, Chiang Mai, Thailand
# Southwest Forestry University, Kunming, China
¤ King Saud University, Riyadh, Saudi Arabia

Corresponding author: Sugantha Gunaseelan ( suganthagunaseelan@gmail.com )

Corresponding author: Malarvizhi Kaliyaperumal ( malar.kaliyaperumal@gmail.com )

Academic editor: Ajay Kumar Gautam
© 2024 Sugantha Gunaseelan, Kezhocuyi Kezo, Samantha C. Karunarathna, Erfu Yang, Changlin Zhao, Abdallah M. Elgorban, Saowaluck Tibpromma, Malarvizhi Kaliyaperumal.
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: Gunaseelan S, Kezo K, Karunarathna SC, Yang E, Zhao C, Elgorban AM, Tibpromma S, Kaliyaperumal M (2024) New species of Tropicoporus (Basidiomycota, Hymenochaetales, Hymenochaetaceae) from India, with a key to Afro-Asian Tropicoporus species. MycoKeys 102: 29-54. https://doi.org/10.3897/mycokeys.102.117067
Open Access

Abstract

The Inonotus linteus complex, predominantly reported from East Asia, Mesoamerica and Caribbean countries, was circumscribed into Tropicoporus as one of the new genera, based on morphological and phylogenetic data. The present paper describes four new species of Tropicoporus from India. Morphological characteristics and phylogenetic analyses, based on ITS and nLSU data, delimited the new species, which are named T. cleistanthicola, T. indicus, T. pseudoindicus and T. tamilnaduensis. The pairwise homoplasy index (PHI) test was done to confirm the distinctive nature of the new species. The traits of Indian species remain distinct from one another, except for the pileate basidiome with the mono-dimitic hyphal system, cystidioles and broadly ellipsoid basidiospores. Descriptions, illustrations, PHI test results and a phylogenetic tree to show the position of the new species are provided. In addition, an identification key to Tropicoporus in Asia and an African species is given.

Key words

DNA, Inonotus linteus complex, mushroom, new species, taxonomy, wood decaying fungi

Introduction

The morpho-taxonomy and phylogenetic analyses, based on the nLSU and ITS genetic markers, revealed that the Inonotus linteus complex comprises two clades and are respectively treated as two new genera, Sanghuangporus and Tropicoporus (Zhou et al. 2015). Tropicoporus is characterised by their annual to perennial, resupinate, effused-reflexed to pileate basidiome with glabrous, uncracked to radially cracked pilear surface, homogeneous to duplex context, with or without a black line. A mono-dimitic or dimitic hyphal system with simple septate generative hyphae, presence or absence of cystidioles, presence of hymenial setae with smooth, fairly thick-walled to thick-walled, yellowish, subglobose to ellipsoid basidiospores are microscopic characteristic features of Tropicoporus (Zhou et al. 2015; Wu et al. 2022).

A total of forty-eight Tropicoporus species have been recorded in MycoBank with fifteen new species and thirty-three new combinations (as of 12 January 2024). Two new species, namely Tropicoporus excentrodendri L.W. Zhou & Y.C. Dai and T. guanacastensis L.W. Zhou, Y.C. Dai & Vlasák have been delimited, based on nLSU and ITS datasets (Zhou et al. 2015). In addition, Tropicoporus boehmeriae (L.W. Zhou & F. Wu) Y. C. Dai & F. Wu, T. drechsleri Salvador-Montoya & Popoff, T. flabellatus V.R.T. Oliveira, J.R.C. Oliveira-Filho, Xavier de Lima & Gibertoni, T. nullisetus Xavier de Lima, V.R.T. Oliveira & Gibertoni, T. stratificans Y.C. Dai & F. Wu. and T. texanus A.A. Brown, D.P. Lawr. & K. Baumgartner were reported across the world, based on the morphological and molecular data (Wu et al. 2015; Coelho et al. 2016; Salvador-Montoya et al. 2018; Brown et al. 2019; Lima et al. 2022). Recently, seven new species viz., T. angustisulcatus Y.C. Dai & F. Wu, T. hainanicus Y.C. Dai & F. Wu, T. lineatus Y.C. Dai & F. Wu, T. minus Y.C. Dai & F. Wu, T. ravidus Y.C. Dai & F. Wu, T. substratificans Y.C. Dai & F. Wu and T. tenuis Y.C. Dai & F. Wu with twenty-four new combinations were reported, based on the combined dataset of ITS and nLSU sequences (Wu et al. 2022). Of the forty-eight legitimate Tropicoporus species, only T. nullisetus was reported without setae (Lima et al. 2022).

Tropicoporus linteus (also known as Phellinus linteus) is used as a renowned Chinese medicine. Due to the presence of P. linteus polysaccharides (PLPs), it may play a vital role in anti-aging, anti-bacterial, anti-inflammation, anti-tumour, anti-oxidant, hepatoprotective and hypoglycaemic processes (Chen et al. 2019). On the other hand, Tropicoporus tropicalis has been reported to cause diseases in humans (Sutton et al. 2005; Haidar et al. 2017; Gupta et al. 2022).

In India, hymenochaetoid fungi from Himachal Pradesh were studied (Kaur et al. 2022). Fourteen hymenochaetoid members were documented from Tamil Nadu (Natarajan and Kolandavelu 1998). Nevertheless, studies on Indian hymenochaetoid fungi, based on molecular data have not been attempted, which makes it difficult to understand their evolutionary history, phylogenetic relationships and accuracy of species delimitation. This study is the first attempt to describe new Tropicoporus species from India, based on morphology and molecular evidence. In addition, an identification key to Afro-Asian Tropicoporus is given.

Materials and methods

Morphological analyses

Eight specimens were collected from parts of Eastern Ghats and the plain region of Tamil Nadu, southern India. Macro-morphological characteristics such as shape, size of basidiome, perennial or annual, colour, texture, margin (acute or obtuse), context (homogenous, duplex with or without black line), tube layer (colour, length, stratification) and pores (size and shape) were examined in the fresh sample and recorded. Colour descriptions were based on the Methuen Handbook (Kornerup and Wanscher 1978). To analyse the micro-morphological characteristics, free-hand sections of dry specimens were mounted in water, 5% potassium hydroxide (KOH) (v/w), cotton blue (CB) and Melzer’s reagent (IK). Sections were studied and photos were taken at magnification up to 1000× using a LABOMED OPTIC-CX BINO LED microscope. The drawings were made using LABOMED CxL2 compound microscope. Microscopic measurements and illustrations were made in 5% KOH solution. Basidiospores measurements (as minimum-mean-maximum) and Q values (length/width ratios) were recorded. The following abbreviations are used: IKI ̄ (inamyloid), IKI+ (amyloid), CB ̄ (acyanophilous), CB+ (cyanophilous), L = mean spore length (arithmetic average of all spores), W = mean spore width (arithmetic average of all spores), Q = (variation in the L/W ratios; and basidium length excludes the lengths of the sterigmata) and n = number of spores measured. For measuring the spores, an average of 50 spores were considered. Specimens in this study were deposited in the Madras University Botany Laboratory (MUBL), Centre for Advanced Studies in Botany, University of Madras, India.

Genomic DNA extraction, PCR amplification and sequencing

Extraction of total genomic DNA from mycelium and dried basidiome followed the protocol of Doyle and Doyle (1987), modified by Góes-Neto et al. (2005). The ITS and nLSU regions were amplified and sequenced with the primers ITS1/ITS4 and LR0R/LR7, respectively (Vilgalys and Hester 1990; White et al. 1990). The polymerase chain reaction (PCR) procedure for ITS was as follows: initial denaturation at 95 °C for 3 min, followed by 32 cycles at 95 °C for 30 s, 52 °C for 30 s and 72 °C for 1 min and a final extension of 72 °C for 3 min. The PCR procedure followed for nLSU was as follows: initial denaturation at 94 °C for 1 min, followed by 34 cycles at 94 °C for 30 s, 45 °C for 30 s and 72 °C for 1.5 min and final extension at 72 °C for 10 min. The PCR products were sequenced at Eurofins Genomics India Pvt. Ltd., Karnataka, India.

Phylogenetic analyses

The dataset comprised ITS and nLSU sequences of Fulvifomes, Inonotus, Phellinus, Phylloporia, Sanghuangporus and Tropicoporus retrieved from GenBank (NCBI), along with the outgroup (Fomitiporella caryophylli, CBS 448.76) and the newly-generated sequences (deposited at GenBank (Sayers et al. 2023); for accession numbers, see Table 1). The dataset was aligned using MEGA X v.10.0.2 configured for Windows and edited manually to increase the alignment similarity (Kumar et al. 2018). The Maximum Likelihood (ML) tree was constructed using raxmlGUI 2.0 (Edler et al. 2020) with the best-fit evolutionary model estimated by jModelTest 2.1.10 with 1000 rapid bootstrap inferences (BS) (Guindon and Gascuel 2003; Darriba et al. 2012). Bayesian Inference (BI) was performed using MrBayes 3.2.7a with two independent runs and six chains of Metropolis-coupled Markov Chain Monte Carlo iterations for 2,000,000 generations and trees were sampled every 100 generations (Ronquist et al. 2012). A proportion of 0. 25% of all trees (nLSU+ITS, ITS, nLSU) were discarded as burn-in. The final alignments and the retrieved topologies were deposited in TreeBASE (http://purl.org/phylo/treebase/phylows/study/TB2:S31000).

Table 1.
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Names, strain numbers, countries of collection and the corresponding GenBank accession numbers of the sequences used in this study.

Species Strain numbers Country Accession numbers
ITS nLSU
Fomitiporella caryophylli CBS 448.76 – AY558611 AY558611
Fulvifomes centroamericanus T JV0611_III Guatemala KX960763 KX960764
F. elaeodendri CMW47825 South Africa MH599094 MH599134
F. nilgheriensis CBS 209.36 USA AY558633 AY059023
F. thailandicus T LWZ 2014073-11 Thailand KR905672 KR905665
Inonotus pachyphloeus Wu 0407.6 Taiwan KP030785 KP030770
Phellinus laevigatus CBS 122.40 USA MH856059 MH867554
P. populicola T CBS 638.75 Finland MH860960 MH872729
Phylloporia nodostipitata FLOR:51153 Brazil KJ639057 KJ631414
Sanghuangporus alpinus Cui12485 China MF772781 MF772799
S. baumii Cui 11769 China MF772784 MF772803
S. lonicericola Dai 8376 China JQ860308 MF772805
S. lonicerinus Dai 17093 China MF772788 MF772807
S. quercicola Dai 13947 China KY328309 MF772809
S. sanghuang Cui 14419 China MF772789 MF772810
S. vaninii DMR 95-1-T North America KU139198 KU139258
S. vitexicola Wu 2006-21 – MT906620 MZ437416
S. weigelae Dai 16077 China MF772794 MF772815
S. zonatus Dai 10841 China JQ860306 KP030775
Tropicoporus angustisulcatus Dai 17409 Brazil MZ484584 MZ437417
T. angustisulcatus T JV 1808/83 French Guiana MZ484585 MZ437418
T. boehmeriae T LWZ 20140729-10 Thailand KT223640 MT319393
T. boehmeriae LWZ 20140729-13 Thailand KT223641 MT319394
Dai 20522 China MZ484586 MZ437419
Dai 20617 China MZ484587 MZ437420
T. cleistanthicola T MUBL1089 India OR272292 OR272337
T. cleistanthicola MUBL1090 India OR272291 OR272336
T. cubensis MUCL 47113 Cuba JQ860324 KP030777
MUCL 47079 Cuba JQ860325 KP030776
T. dependens JV 0409/12-J USA KC778777 MF772818
T. detonsus CBS 617.89 – AF534077 AY059037
IDR 1300012986 USA KF695121 KF695122
T. drechsleri T CTES:570140 Argentina MG242439 MG242444
T. drechsleri CTES:570144 Argentina MG242437 MG242442
T. excentrodendri Yuan 6234 China KP030791 –
Yuan 6229 China KP030789 –
T. flabellatus T VRTO873 Brazil MT908376 MT906643
T. guanacastensis O 19228 Costa Rica KP030794 –
T. guanacastensis T JV 1408_25 Costa Rica KP030793 KP030778
T. hainanicus T Dai 17705 China MZ484588 MZ437421
T. indicus T MUBL1083 India OR272293 OR272338
T. indicus MUBL1084 India OR272294 OR272339
T. lineatus T Dai 21196 Malaysia MZ484594 MZ437426
T. linteus JV 0904/64 USA JQ860322 JX467701
T. linteus JV 0904/140 USA JQ860323 KP030780
T. minor T Dai 21139 China MZ484592 MZ437424
T. minus Dai 18487A China MZ484590 MZ437422
Dai 21183 China MZ484593 MZ437425
T. nullisetus T VXLF616 Brazil MN795129 MN812261
T. nullisetus VRTO195 Brazil MN795118 MN812254
T. pseudoindicus T MUBL1087 India OR272295 OR272340
T. pseudoindicus MUBL1088 India OR272296 OR272341
T. pseudolinteus JV0402/35-K Venezuela KC778781 MF772820
JV 0312/22.10-J Venezuela KC778780 –
T. ravidus T Dai 18165 China MZ484595 MZ437427
T. rudis O 915614 Rwanda KP030796 –
O 915617 Tanzania KP030797 MH101016
T. sideroxylicola JV 1207/4.3-J USA KC778783 –
T. sideroxylicola T JV 0409/30-J USA KC778782 –
T. stratificans T SMDB 14732 Brazil KM199689 –
T. stratificans VRTO884 Brazil MN795124 MN812266
T. substratificans T JV 1908/80 French Guiana MZ484597 MZ437429
T. tamilnaduensis T MUBL1085 India OR272297 OR272343
T. tamilnaduensis MUBL1086 India – OR272344
T. tenuis T Dai 19699 China MZ484598 MZ437430
T. tenuis Dai 19724 China MZ484599 MZ437431
T. texanus T CBS 145357 USA NR_168219 NG_068906
T. texanus TX8 USA MN108123 MN113949
T. tropicalis UTHSC 02-617 USA AY641432 –
UAMH 10376 USA AY599487 –

T = Type material and “-” refers to the data unavailability. Sequences generated from the present study are indicated in bold.

Genealogical concordance phylogenetic species recognition analysis

Genealogical concordance phylogenetic species recognition analysis (GCPSR) by the pairwise homoplasy index (PHI) test was used to determine the recombination level within closely-related species (Bruen et al. 2006). The data were analysed by the software SplitsTree 4 (Bruen et al. 2006; Huson and Bryant 2006). The relationships between closely related taxa were visualised by constructing split graphs from concatenated datasets, using the LogDet transformation and splits decomposition options. If the PHI test value is (Φw) ≤ 0.05, it indicates significant recombination within the dataset. This is an important method to provide further evidence to justify a species. All results are shown in Fig. 1.

Figure 1. 

Split graphs show the results of the PHI test of the new species, Tropicoporus indicus, T. tamilnaduensis, T. pseudoindicus, T. cleistanthicola and their most closely-related species T. rudis, using LogDet transformation and split decomposition options. The PHI test result Φw ≤ 0.05 indicates that there is a significant recombination within the dataset.

Results

Phylogenetic analyses

In total, eight new sequences of the ITS and seven new sequences of the nLSU regions were generated and submitted to GenBank (Table 1). Additionally, 62 taxa (52 nLSU and 62 ITS sequences) were retrieved from GenBank (Table 1). The combined nLSU and ITS dataset were aligned and the multiple sequence alignment consists of 1,820 characters (914 for nLSU and 902 for ITS) of which 1,017 were constant, 962 were variable and 570 (31%) were parsimony informative. The best-fit evolutionary model (GAMMA+P-Invar Model) was estimated by jModelTest 2.1.10 for the combined datasets. The Maximum Likelihood (ML) trees were constructed using raxmlGUI 2.0 with 1,000 rapid bootstrap inferences (BS). The Bayesian analysis was run for 2,000,000 generations and the average standard deviation reached 0.010166. The phylogenetic topology was selected from Bayesian analysis. The Maximum Likelihood bootstrap values ≥ 60% and the Bayesian posterior probabilities ≥ 0.90 are summarised in Fig. 2.

Figure 2. 

Molecular phylogeny of four new Indian Tropicoporus species and other hymenochaetoid species inferred from combined ITS and nLSU sequences. The topology is from the Bayesian analysis. Maximum Likelihood bootstrap values and Bayesian posterior probabilities, above 60% and 0.9, respectively, are labelled at the nodes. The newly-generated sequences are coloured and bold; the type specimens are in bold.

Taxonomical descriptions of the four novel species of Tropicoporus

Tropicoporus cleistanthicola S. Gunaseelan & M. Kaliyaperumal, sp. nov.

MycoBank No: 849484
Figs 3, 4

Etymology

The specific epithet cleistanthicola (Lat.) refers to the host Cleistanthus collinus.

Diagnosis

Tropicoporus cleistanthicola is characterised by perennial, effused-reflexed to pileate, applanate to triquetrous basidiome with narrowly zonate, glabrous, meagrely warted pilear surface, acute margin, homogenous context, mono-dimitic hyphal system, presence of cystidioles and subglobose to broadly ellipsoid basidiospores measuring 4.7–5.4 × 4.2–4.9 μm.

Figure 3. 

Tropicoporus cleistanthicola (MUBL1089 holotype) A basidiomata (Holotype) B pore surface C cross-section of basidiome (arrows indicating stratified tube layers) D hymenial setae E–H basidiospores: E basidiospores in water F basidiospores in KOH G basidiospore in cotton blue H basidiospore in Melzer’s reagent. Scale bars: 1 cm (A–C); 5 µm (D–H).

Type

India, Tamil Nadu, Thiruvannamalai District, Jawadhu Hills, 12°54'24"N, 78°87'75"E; 15 Nov 2019; Sugantha Gunaseelan; on a living angiosperm tree (Cleistanthus collinus); SMK-PMP11 (MUBL1089; Holotype); GenBank: OR272292 (ITS); OR272337 (nLSU).

Figure 4. 

Tropicoporus cleistanthicola (MUBL1089 holotype) A contextual hyphae B tramal hyphae C hymenial setae D cystidioles E basidioles F basidia G basidiospores. Scale bars: 5 µm.

Description

Basidiome perennial, pileate, solitary, hard corky and without distinctive odour or taste when fresh, woody hard and light in weight when dry. Pilei effused-reflexed to pileate, dimidiate, triquetrous in section, projecting up to 4 cm, 6.5 cm wide and 3 cm thick at the base; Pileal surface narrowly zonate, glabrous, meagrely warted near attachment, yellowish-brown (5E6; 5E8) to dark brown (6F5), turning dark brown (7F4) to greyish-brown (6F3). Margin acute, 1 mm thick, light brown (6D5). Pore surface brown (6E6) to dark brown (6F7); sterile margin up to 2 mm wide, light brown (6D5); pores circular, 5–7 per mm. Context homogenous, up to 1.5 cm thick, brown (6E8). Tubes up to 0.5 cm long, tube layers distinctly stratified, each stratum up to 2 mm, brown (6E7).

Hyphal structures

Hyphal system monomitic in the context and dimitic in the trama, tissue darkening with KOH without hyphal swelling.

Context

Generative hyphae, thin to thick-walled, hyaline to golden yellow, simple septate, rarely branched, 2–5 μm diam.

Trama

Generative hyphae, dominant, thin to thick-walled, hyaline to pale yellow, septate, occasionally branched, 2–4 μm diam. Skeletal hyphae thick-walled with narrow to wide lumen, yellowish-brown, aseptate, unbranched, 2–3.5 μm diam.

Hymenium

Hymenial setae dark brown, thick-walled, ventricose to subulate with sharp to blunt tips, 5–32 × 4–5.5 μm. Cystidia absent. Cystidioles hyaline, thin-walled, ventricose to fusoid with elongated tapering apical portion, 7–45 × 2–5 μm. Basidia clavate to broadly clavate, 7–15 × 2.7–6.2 μm, with four sterigmata and a simple septum at the base. Basidioles clavate, 5–13 × 3.5–6 μm. Basidiospores broadly ellipsoid to subglobose, pale yellow in water, turning golden yellow to brown in KOH, thick-walled, smooth, CB ̄, IKI ̄, (4.7–) 4.9–5.2 (–5.4) × (4.2–) 4.5–4.7 (–4.9) μm (n = 50/2), Q = 1.1 (Q range 1.05–1.2).

Habitat and distribution

Basidiomes were found on living trees of Cleistanthus collinus (Phyllanthaceae), distributed in Jawadhu Hills, Thiruvannamalai District, Tamil Nadu, India.

Additional material examined

India, Tamil Nadu, Thiruvannamalai District, Jawadhu Hills; 12°51'20"N, 78°73'71"E; 15 Nov 2019; Sugantha Gunaseelan; on a living angiosperm tree (Cleistanthus collinus); SMK-PMP14 (MUBL1090, Paratype); GenBank: OR272291 (ITS); OR272336 (nLSU).

Notes

The present phylogenetic study indicated that T. cleistanthicola is sister to T. rudis with significant support (92% ML/0.9 BPP). However, T. rudis has applanate basidiomes with fulvous, velvety, concentrically zonate, matted, rimose pilear surface, whereas T. cleistanthicola has triquetrous basidiome and glabrous pilear surface with infrequent warts without cracks. Tropicoporus cleistanthicola and T. rudis are comparable only in mono-dimitic hyphal system and T. rudis lacks cystidioles and has larger basidiospores (4.9−6 × 4−4.8 μm) (Wu et al. 2022). Despite sharing pileate basidiomes, mono-dimitic hyphal system and presence of cystidioles in T. linteus, T. cleistanthicola differs by having effused-reflexed to pileate, narrowly zonate, meagrely warted pilear surface (Tian et al. 2013; Wu et al. 2022). Tropicoporus cleistanthicola resembles T. angustisulcatus, T. dependens, T. excentrodendri, T. substratificans and T. lineatus by sharing pileate, triquetrous basidiomes with concentrically zonation and presence of cystidioles, but T. cleistanthicola differs by having a mono-dimitic hyphal system and spore size (4.7–5.4 × 4.2–4.9 μm) (Zhou et al. 2015; Wu et al. 2022). Tropicoporus cleistanthicola and T. drechsleri are similar in having pileate basidiomes and a mono-dimitic hyphal system with the presence of cystidioles, but T. cleistanthicola differs by having smaller pores (5–7 pores/mm) and larger basidiospores (Salvador-Montoya et al. 2018). Except for sharing a mono-dimitic hyphal system and indistinctly stratified tube layers, T. cleistanthicola differs from T. flabellatus and T. guanacastensis in pores (size and shape), basidiospore shape and absence of cystidioles (Zhou et al. 2015; Lima et al. 2022).

Tropicoporus indicus S. Gunaseelan & M. Kaliyaperumal, sp. nov.

MycoBank No: 849482
Figs 5, 6

Etymology

The species epithet “indicus” (Lat.): referring to the species being collected from India.

Diagnosis

Tropicoporus indicus is characterised by applanate to meagrely triquetrous basidiome with concentrically zonate, sulcate, glabrous, deeply cracked to rimose pilear surface, homogenous context, acute margin, mono-dimitic hyphal system, presence of cystidioles, subglobose to broadly ellipsoid basidiospores measuring 5–6 × 4.2–4.9 μm.

Figure 5. 

Tropicoporus indicus (MUBL1083 holotype) A basidiomata (Holotype) B basidiome (SMK-MK2a- Isotype) C pore surface D cross-section of basidiome (arrows indicating stratified tube layers) E hymenial setae F cystidioles G–J basidiospores: G basidiospores in water H basidiospores in KOH I basidiospores in cotton blue J basidiospores in Melzer’s reagent. Scale bars: 1 cm (A–D); 5 µm (E–J).

Type

India, Tamil Nadu, Kallakurichi District, Kalvarayan Hills; 11°91'30"N, 78°57'86"E; 29 Sep 2022; Sugantha Gunaseelan; on living angiosperm tree of Albizia amara; SMK- MK2 (MUBL1083, Holotype); GenBank: OR272293 (ITS); OR272338 (nLSU).

Figure 6. 

Tropicoporus indicus (MUBL1083 holotype) A contextual hyphae B tramal hyphae C hymenial setae D cystidioles E basidioles F basidia G basidiospores. Scale bars: 5 µm.

Description

Basidiome perennial, pileate, woody and without distinctive odour or taste when fresh, hard when dry. Pilei applanate to meagrely triquetrous, projecting up to 5.5 cm, 7 cm wide and 4 cm thick at the base; pileal surface concentrically zonate, sulcate, glabrous, deeply cracked to rimose near attachment, dark brown (7E4), greyish-brown (7F3). Margin velutinate, 2 mm thick, acute, brown (6E7). Pore surface light brown (5D5) to yellowish-brown (5E7); pores circular, 4–6 per mm. Context homogenous, up to 0.8 cm thick, brown (6E8) to dark brown (6F8). Tubes woody hard, up to 2.5 cm long, brown (6E7); tube layers stratified, each stratum up to 0.5 cm long.

Hyphal structures

Hyphal system monomitic in the context and dimitic in the trama, tissue darkening with KOH without swelling

Context

Generative hyphae, thin to thick-walled, hyaline to golden yellow, simple septate, rarely branched, 2–5 μm diam.

Trama

Generative hyphae dominant, thin to thick-walled, hyaline to pale yellow, septate, occasionally branched, 2–4.5 μm diam. Skeletal hyphae thick-walled with narrow to wide lumen, yellowish-brown, aseptate, unbranched, 2–4 μm diam.

Hymenium

Hymenial setae dark brown, thick-walled, ventricose to subulate with sharp to blunt tips, 7–28 × 3–5 μm. Cystidia absent. Cystidioles hyaline, thin-walled, ventricose to fusoid with elongated tapering apical portion, 5–21 × 3–5 μm. Basidia clavate to broadly clavate, 7–17 × 3–6 μm, with four sterigmata and a simple septum at the base. Basidioles clavate, 5–14 × 3–5 μm. Basidiospores broadly ellipsoid to subglobose, pale yellow in water, turning golden yellow to brown in KOH, thick-walled, smooth, CB ̄, IKI ̄, (5–) 5.3–5.8 (– 6) × (4.2–) 4.7–4.9 μm (n = 50/2), Q = 1.16 (Q range 1.05–1.3).

Habitat and distribution

Basidiomes were found on living trees of Fabaceae members (Albizia amara and Prosopis cineraria), distributed in Kalvarayan Hills, Kallakurichi District, Tamil Nadu, India.

Additional material examined

India, Tamil Nadu, Kallakurichi District, Kalvarayan Hills; 11°90'39"N, 78°55'69"E; on a living angiosperm tree (Prosopis cineraria); 29 Sep 2022; Kezhocuyi Kezo; SMK-MK2a (MUBL1084, Paratype); GenBank: OR272294 (ITS); OR272339 (nLSU).

Notes

Phylogenetically, Tropicoporus indicus was recovered in the T. linteus clade. Tropicoporus indicus is similar to T. linteus by sharing, pileate, dimidiate basidiomes, concentrically sulcate pilear surface, zonate context, smaller pores (5–7/mm), a mono-dimitic hyphal system and presence of cystidioles. While varying in the nature of cracks, T. linteus has more or less cracked basidiomes, T. indicus has irregular deep cracks in basidiomes, with larger basidiospores (T. linteus 4.8−5.7 × 3.8–4.8 μm and T. indicus 5–6 × 4.2–4.9 μm) (Tian et al. 2013; Wu et al. 2022). Tropicoporus indicus and T. rudis share a mono-dimitic hyphal system, but T. indicus differs from T. rudis in having zonate, sulcate, deeply cracked to rimose basidiomes and larger pores (4–6/mm). In these regards, T. rudis is characterised by fulvous, velvety, concentrically zonate, matted, rimose basidiome and smaller pores (6–7/mm) (Wu et al. 2022). Tropicoporus indicus differs from T. angustisulcatus, T. excentrodendri, T. lineatus and T. substratificans in having mono-dimitic hyphal system and a cracked basidiome (Zhou et al. 2015; Wu et al. 2022). Tropicoporus indicus and T. flabellatus are similar in having a mono-dimitic hyphal system, but differ significantly by having concentrical zones, sulcate, glabrous, deeply-cracked to rimose pilear surface with larger pores (4–6/mm) and broadly ellipsoid to subglobose spores (5–6 × 4.2–4.9 μm). Tropicoporus flabellatus, in contrast, has a velutinate pilear surface, uncracked basidiomes with smaller pores (7–9/mm) and smaller basidiospores (4.5–5 × 3.5–4 μm) (Lima et al. 2022). Tropicoporus indicus and T. guanacastensis are similar in having sulcate, cracked basidiome, stratified tube, mono-dimitic hyphal system and ventricose setae. However, the former differs in larger pores (4–6/mm) and larger basidiospores (T. indicus 5–6 × 4.2–4.9 μm vs. T. guanacastensis 4.1–5 × 3.1–4 μm) (Zhou et al. 2015). Tropicoporus indicus and T. drechsleri share concentrically sulcate deeply-cracked pilei with mono-dimitic hyphal system, larger pores (< 6/mm) and presence of cystidioles, but the South American species differs in basidiospore size (4–5.5 × 3–4.5 μm) (Salvador-Montoya et al. 2018).

Tropicoporus pseudoindicus S. Gunaseelan & M. Kaliyaperumal, sp. nov.

MycoBank No: 849483
Figs 7, 8

Etymology

The species pseudoindicus signifies the close morphological and phylogenetic relationships with the species Tropicoporus indicus.

Diagnosis

Tropicoporus pseudoindicus is characterised by applanate to meagrely ungulate to triquetrous basidiome with broadly zonate, distinctly cracked by radial fissures, sulcate pilear surface, duplex context with black line, acute to obtuse margin, pores 6–8/mm, mono-dimitic hyphal system, presence of cystidioles, subglobose to broadly ellipsoid basidiospores measuring 4–5.2 × 3.7–4.7 μm.

Figure 7. 

Tropicoporus pseudoindicus (MUBL1085 holotype) A basidiomata (Holotype) B pore surface C cross-section of basidiome (arrows indicating stratified tube layers and duplex context with black line) D hymenial setae E–H basidiospores: E basidiospores in water F basidiospores in KOH G basidiospores in cotton blue H basidiospores in Melzer’s reagent. Scale bars: 1 cm (A–C); 5 µm (D–H).

Type

India, Tamil Nadu, Kallakurichi District, Kalvarayan Hills; 11°86'98"N, 78°55'68"E; 29 Sep. 2022; Sugantha Gunaseelan; on a living angiosperm tree (Albizia amara); SMK-MK4 (MUBL1087, Holotype); GenBank: OR272295 (ITS); OR272340 (nLSU).

Figure 8. 

Tropicoporus pseudoindicus (MUBL1085 holotype) A contextual hyphae B tramal hyphae C hymenial setae D cystidioles E basidioles F basidia G basidiospores. Scale bars: 5 µm.

Description

Basidiome perennial, pileate, woody and without distinctive odour or taste when fresh, hard and light in weight when dry. Pilei applanate, meagrely ungulate to triquetrous, dimidiate, projecting up to 5 cm, 8 cm wide and 3.5 cm thick at base; pileal surface broadly zonate, distinctly cracked by radial fissures, sulcate, brown (6E8), dark brown (7F4) to greyish-brown (6F3). Margin acute to obtuse, up to 3 mm thick, light brown (6D5). Pore surface brown (6E6) to dark brown (7E6); sterile margin brown (6E6), up to 2 mm wide; pores circular, 6–8 per mm. Context duplex with black line, woody hard, up to 1.2 cm thick, several black lines present along context, brown (6E7) to dark brown (7F6). Tubes up to 1.5 cm long, annual layers distinct, each stratum up to 0.3 cm, brown (7E8) to dark brown (6F8).

Hyphal structures

Hyphal system monomitic in the context and dimitic in the trama, tissue darkening with KOH without swelling.

Context

Generative hyphae, thin to thick-walled, hyaline to golden yellow, simple septate, rarely branched, 2–5 μm diam.

Trama

Generative hyphae, dominant, thin to thick-walled, hyaline to pale yellow, septate, occasionally branched, 2–4 μm diam. Skeletal hyphae, thick-walled with narrow to wide lumen, yellowish-brown, aseptate, unbranched, 2–3.5 μm diam.

Hymenium

Hymenial setae dark brown, thick-walled, ventricose to subulate with sharp to blunt tips, rarely with lateral appendage, 5–18 × 3–5.5 μm. Cystidia absent. Cystidioles hyaline, thin-walled, ventricose to fusoid with elongated tapering apical portion, 7–52 × 2.5–5.2 μm. Basidia clavate to broadly clavate, 7–15 × 2.7–6.2 μm, with four sterigmata and a simple septum at the base. Basidioles clavate, 5–13 × 3.5–6 μm. Basidiospores broadly ellipsoid to subglobose, pale yellow in water, turning golden yellow to brown in KOH, thick-walled, smooth, CB ̄, IKI ̄, (4–) 4.2–5 (–5.2) × (3.7–) 4–4.5 (–4.7) μm (n = 50/2) and Q = 1.14 (Q range 1.05–1.25).

Habitat and distribution

Basidiomes were found on living trees of Fabaceae members (Albizia amara and Peltophorum pterocarpum), distributed in Kalvarayan Hills, Kallakurichi District, Tamil Nadu, India.

Additional material examined

India, Tamil Nadu, Kallakurichi District, Kalvarayan Hills; 11°87'33"N, 78°42'78"E; 29 Sep 2022; Kezhocuyi Kezo; on a living angiosperm tree (Peltophorum pterocarpum); SMK-MK4a (MUBL1088, Paratype); GenBank: OR272296 (ITS); OR272341 (nLSU).

Notes

Tropicoporus pseudoindicus and T. drechsleri, share similar characteristics, such as applanate basidiomes with mono-dimitic hyphal system and the presence of cystidioles; however, T. pseudoindicus differs in having smaller pores (6–8/mm) and larger basidiospores (T. pseudoindicus 4–5.2 × 3.7–4.7 μm vs. T. drechsleri 4–5.5 × 3–4.5 μm) (Salvador-Montoya et al. 2018). Tropicoporus pseudoindicus resembles T. rudis in having a mono-dimitic hyphal system, presence of cystidioles, and basidiospore shape, but differs from T. rudis in having distinctly cracked, fissured to sulcate pilei, duplex context and smaller basidiospores (4–5.2 × 3.7–4.7 μm) (Vlasák et al. 2013). Tropicoporus pseudoindicus differs from T. guanacastensis in having cystidioles and subglobose to broadly ellipsoidal spores (T. pseudoindicus 4–5.2 × 3.7–4.7 μm vs. T. guanacastensis 4.1–5.0 × 3.1–4.0 μm) (Tian et al. 2013). Tropicoporus pseudoindicus and T. linteus share similar pileate basidiomes with sulcate pilear surface, smaller pores (5–7/mm), mono-dimitic hyphal system and presence of cystidioles. However, the former differs in basidiospore size (T. linteus 4.8−5.7 × 3.8–4.8 μm vs. T. pseudoindicus 4–5.2 × 3.7–4.7 μm) (Tian et al. 2013; Wu et al. 2022). Tropicoporus pseudoindicus and T. flabellatus are similar in their mono-dimitic hyphal system, but differ significantly in pilear characteristics, absence of cystidioles and size and shape of basidiospores (T. flabellatus 4.5–5 × 3.5–4 μm vs. T. pseudoindicus (4–) 4.2–5 (–5.2) × (3.7–) 4–4.5 (–4.7) μm) (Lima et al. 2022). Tropicoporus pseudoindicus differs from some other reported Tropicoporus species (namely T. angustisulcatus, T. excentrodendri, T. lineatus and T. substratificans) in having concentrically zonate, glabrous, distinctly cracked pileal surface and a mono-dimitic hyphal system (Zhou et al. 2015; Wu et al. 2022).

Tropicoporus tamilnaduensis M. Kaliyaperumal & S. Gunaseelan, sp. nov.

MycoBank No: 849481
Figs 9, 10

Etymology

The species epithet tamilnaduensis refers to the locality of the type specimen (Tamil Nadu).

Diagnosis

Tropicoporus tamilnaduensis is characterised by applanate to meagrely ungulate basidiome with glabrous, broadly zonate, sulcate and deeply irregularly cracked pilear surface, homogenous context, obtuse margin, pores 4–5/mm, mono-dimitic hyphal system, presence of cystidioles, subglobose to broadly ellipsoid basidiospores measuring 4.5–5.7 × 3.5–4.7 μm.

Figure 9. 

Tropicoporus tamilnaduensis (MUBL1085 holotype) A basidiomata (Holotype) B pore surface C cross-section of basidiome (arrows indicating stratified tube layers) D hymenial setae E–H basidiospores: E basidiospore in water F basidiospores in KOH G basidiospores in cotton blue H basidiospores in Melzer’s reagent. Scale bars: 1 cm (A–C); 5 µm (D–H).

Type

India, Tamil Nadu, Cuddalore District, Thaiyalkunampattinam, Kanni Tamil Nadu; 11°59'18"N, 79°60'17"E; 31 Dec 2022; Malarvizhi Kaliyaperumal; on a living angiosperm tree (Madhuca longifolia); MKDM02 (MUBL1085, holotype); GenBank: OR272297 (ITS); OR272343 (nLSU).

Figure 10. 

Tropicoporus tamilnaduensis (MUBL1085 holotype) A tramal hyphae B contextual hyphae C hymenial setae D cystidioles E basidioles F basidia G Basidiospores. Scale bars: 5 µm.

Description

Basidiome perennial, pileate, without distinctive odour or taste when fresh, woody hard and light in weight when dry. Pilei applanate to meagrely ungulate, projecting up to 5 cm, 8 cm wide and 4 cm thick at base; pileal surface glabrous, broadly zonate, sulcate, deeply irregularly cracked near attachment, brown (6E7), yellowish-brown (5F4) to golden brown (7F7) turning greyish-brown (5F3). Margin obtuse, 4 mm thick, light brown (6D5). Pore surface brown (6E6), sterile margin yellowish-brown (5E6), up to 2 mm wide; pores circular, 4–5 per mm; dissepiments thick, entire. Context homogenous, zonate, brown (6D7) to dark brown (6F8), woody hard, up to 2 cm thick. Tubes brown (6E6), up to 2 cm long, annual layers distinct, each stratum up to 0.3 cm long.

Hyphal structures

Hyphal system monomitic in the context and dimitic in the trama, tissue darkening with KOH without hyphal swelling.

Context

Generative hyphae, thin to thick-walled, hyaline to golden yellow, simple septate, rarely branched, 2–5 μm diam.

Trama

Generative hyphae, dominant, thin to thick-walled, hyaline to pale yellow, septate, occasionally branched, 2–4 μm diam. Skeletal hyphae, thick-walled with narrow to wide lumen, yellowish-brown, aseptate, unbranched, 2–3.5 μm diam.

Hymenium

Hymenial setae dark brown, thick-walled, ventricose to subulate with sharp to blunt tips, 6–19 × 3.8–5 μm. Cystidia absent. Cystidioles hyaline, thin walled, ventricose to fusoid with elongated tapering apical portion, 10–45 × 2–5 μm. Basidia clavate to broadly clavate, 7–15 × 2.7–6.2 μm, with four sterigmata and a simple septum at the base. Basidioles clavate, 5–13 × 3.5–6 μm. Basidiospores broadly ellipsoid to subglobose, pale yellow in water, turning golden yellow to brown in KOH, thick-walled, smooth, CB ̄, IKI ̄, (4.5–) 4.7–5.5 (–5.7) × (3.5–) 3.7–4.5 (–4.7) μm (n = 50/2), Q = 1.13 (Q range 1.05–1.25).

Habitat and distribution

Basidiomes are found on living trees of Madhuca longifolia and Prosopis cineraria, distributed in Cuddalore District, Tamil Nadu, India.

Additional material examined

India, Tamil Nadu, Cuddalore District, Thaiyalkunampattinam, Kanni Tamil Nadu; 11°50'14"N, 79°54'14"E; 31 Dec 2022; Malarvizhi Kaliyaperumal; on a living angiosperm tree (Prosopis cineraria); MKDM02a (MUBL1086, Paratype); GenBank: OR272344 (nLSU).

Notes

Tropicoporus tamilnaduensis and T. linteus are similar in having pileate sulcate basidiomes, zonate context and a mono-dimitic hyphal system with cystidioles. However, T. tamilnaduensis differs from T. linteus in deeply-cracked basidiomes and smaller basidiospores (Tian et al. 2013; Wu et al. 2022). Tropicoporus tamilnaduensis and T. rudis share a homogenous context, a mono-dimitic hyphal system and subglobose to broadly ellipsoid basidiospores, but T. tamilnaduensis differs in having zonate, sulcate, deeply irregularlycracked basidiome and larger pores (4–5/mm) (Wu et al. 2022). Tropicoporus tamilnaduensis differs from T. angustisulcatus, T. lineatus and T. substratificans in having sulcate and deeply cracked basidiomes and a mono-dimitic hyphal system, while T. angustisulcatus, T. lineatus and T. substratificans have basidiomes with velutinate to glabrous, uncracked pilear surface and a dimitic hyphal system (Zhou et al. 2015; Wu et al. 2022). Tropicoporus tamilnaduensis resembles T. excentrodendri, T. dependens and T. sideroxylicola by sharing concentrically zonate, sulcate, cracked to rimose pilear surface; however, the former differs by having a mono-dimitic hyphal system (Zhou et al. 2015; Salvador-Montoya et al. 2018). Tropicoporus tamilnaduensis and T. guanacastensis are similar in having a mono-dimitic hyphal system; however, T. tamilnaduensis has ungulate, sulcate, deeply irregularly cracked basidiomes with larger pores (4–7/mm) and broadly ellipsoid to subglobose spores (4.5–5.7 × 3.5–4.7 μm) (Zhou et al. 2015). Although sharing a mono-dimitic hyphal system, T. tamilnaduensis differs from T. flabellatus by having sulcate, deeply irregularly cracked basidiomes, cystidioles and larger pores (4–7/mm) with homogenous context (Lima et al. 2022). Tropicoporus tamilnaduensis varies from T. drechsleri by having sulcate, deeply irregularly cracked basidiomes and broadly ellipsoid to ellipsoid basidiospores (4.5–5.7 × 3.5–4.7 μm) (Salvador-Montoya et al. 2018).

Discussion

Recently, the Inonotus linteus complex has gained attention because of its medicinal values and as an emerging potential pathogen in plants (Dai et al. 2009; Dai 2010), humans (Sutton et al. 2005; Haidar et al. 2017; Gupta et al. 2022) and dogs (Hevia et al. 2019). Zhou et al. (2015) segregated the I. linteus complex into two new genera viz. Sanghuangporus Sheng H. Wu, L.W. Zhou & Y.C. Dai and Tropicoporus L.W. Zhou, Y.C. Dai & Shen. H. Wu. Since then, many new species/combinations from tropical countries, especially from China followed by the Americas were introduced (Salvador-Montoya et al. 2018; Brown et al. 2019; Wu et al. 2022). Tropicoporus is characterised by its annual to perennial, resupinate, effused-reflexed to pileate basidiomes with mono-dimitic, dimitic hyphal system, ellipsoid to subglobose basidiospores. To date, twenty-three legitimate species are accepted under Tropicoporus, of which eleven were from tropical American countries, seven were from East Asian countries and one each from Africa, Costa Rica, Cuba and French Guiana.

The Bayesian phylogram illustrated in the present study is consistent with the previous studies (Coelho et al. 2016; Salvador-Montoya et al. 2018; Brown et al. 2019; Lima et al. 2022). The four new Tropicoporus species from Tamil Nadu, India, fit well within the Tropicoporus clade but formed a unique, distinct lineage that was the sister clade to T. rudis (earlier treated as Xanthochrous rudis). The T. rudis clade consists of strictly African collections (92% BS, 1.00 BPP) in the phylogeny (Fig. 1). This clade, in turn, forms the sister clade to a clade composed of T. stratificans, T. substratificans and T. linteus with 62% BS, 0.96 BPP.

The Eastern Ghats has discontinuous mountain ranges with hills ranging from 1,100 to 1,600 m with luxuriant vegetation of tropical evergreen to deciduous, thorn forest or scrub jungle that harbours diverse groups of wood rot fungi. This is the first report of the genus Tropicoporus from the Eastern Ghats of Tamil Nadu with three novel species, viz. T. cleistanthicola, T. indicus and T. pseudoindicus.

Tropicoporus cleistanthicola, T. tamilnaduensis, T. indicus and T. pseudoindicus are characterised by their perennial, pileate basidiomes with mono-dimitic hyphal system, presence of cystidioles and hymenial setae, smooth, thick-walled, coloured and inamyloid basidiospores (Table 2). However, there is significant variation in their basidiome characteristics, pore (shape and size) and basidiospore (shape and size). Tropicoporus cleistanthicola differs from the other three species in having effused-reflexed to pileate, sulcate, and narrowly zonate basidiome with infrequent warts. Tropicoporus tamilnaduensis differs in irregularly cracked basidiome with glabrous, sulcate and irregularly cracked, ungulate basidiome and smaller basidiospores (4.5–5.4 × 3.5–4.7 μm), while T. indicus has regularly cracked and concentrical zonate basidiome, glancing pore surface and larger basidiospores (5–6 × 4.2–4.9 μm). Morphologically, T. pseudoindicus is similar to T. indicus in sharing concentrically zonate, glabrous and rimose with maturity, mono-dimitic hyphal system and presence of cystidioles, while T. pseudoindicus differs by having sulcate deeply cracked, radially fissured basidiome, homogenous context and smaller basidiospores. Our Indian Tropicoporus species (Tropicoporus cleistanthicola, T. tamilnaduensis, T. indicus and T. pseudoindicus) could be easily distinguished by its pileate basidiomes and mono-dimitic hyphal system from the other Tropicoporus resupinate species (T. boehmeriae, T. hainanicus, T. minus, T. ravidus, T. stratificans, T. tenuis and T. texanus) (Wu et al. 2015; Coelho et al. 2016; Brown et al. 2019; Wu et al. 2022).

Table 2.
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Synoptic comparison of characteristics amongst species of the newly-reported Tropicoporus from India.

Species Basidiomata Context Margin Pores /mm Hyphal system Setae (in μm) Cystidioles (in μm) Basidiospores (in μm) Q value (Q range)
T. cleistanthicola Effused-reflexed to pileate, applanate to triquetrous basidiome with narrowly zonate, glabrous, meagrely warted pilear surface Homogenous Acute 5–7 Mono-Di 5–32 × 4–5.5 7–45 × 2–5 (4.7–) 4.9–5.2 (–5.4) × (4.2–) 4.5–4.7 (–4.9) 1.1 (1.05–1.2)
T. indicus Applanate to meagrely triquetrous basidiome with concentrically zonate, sulcate, glabrous, deeply cracked to rimose pilear surface Homogenous Acute 4–6 Mono-Di 7–28 × 3–5 5–21 × 3–5 (5–) 5.3–5.8 (– 6) × (4.2–) 4.7–4.9 1.16 (1.05–1.3)
T. pseudoindicus Applanate, meagrely ungulate to triquetrous basidiome with broadly zonate, distinctly cracked by radial fissures, sulcate pilear surface Duplex with blackline Acute to obtuse 6–8 Mono-Di 5–18 × 3–5.5 7–52 × 2.5–5.2 (4–) 4.2–5 (–5.2) × (3.7–) 4–4.5 (–4.7) 1.14 (1.05–1.25)
T. tamilnaduensis Applanate to meagrely ungulate basidiome with glabrous, broadly zonate, sulcate and deeply irregularly cracked pilear surface Homogenous Obtuse 4–5 Mono-Di 6–19 × 3.8–5 10–45 × 2–5 (4.5–) 4.7–5.4 (–5.7) × (3.5–) 3.7–4.5 (–4.7) 1.13 (1.05–1.25)

Key to species of Tropicoporus in the Afro-Asian region

1 Basidiocarps resupinate to effused-reflexed 2
– Basidiocarps distinctly pileate 7
2 Basidiocarps annual to biennial 3
– Basidiocarps perennial 6
3 Basidiospores cyanophilic T. tenuis
– Basidiospores acyanophilic 4
4 Basidiocarp resupinate to effused reflexed, pileal surface tomentose to hispid basidiospores > 3 μm in length T. excentrodendri
– Basidiocarp resupinate, basidiospores < 3 μm in length 5
5 Dissepiments lacerate, context layer present between tube layers T. hainanicus
– Dissepiments entire, context layer absent between tub layers T. boehmeriae
6 Basidiocarp resupinate, cystidioles present, pores 10–12/mm T. minus
– Basidiocarp cushion-shaped, cystidioles absent, pores 8–10/mm T. ravidus
7 Hyphal system strictly dimitic T. lineatus
– Hyphal system mono-dimitic, dimitic in trama 8
8 Context homogenous 9
– Context duplex with black line T. pseudoindicus
9 Effused reflexed to pileate, uncracked basidiome T. cleistanthicola
– Applanate to ungulate or triquetrous, cracked pilear surface 10
10 Pores > 6/mm, cyanophilic basidiospores T. rudis
– Pores < 6/mm, acyanophilic basidiospores 11
11 Applanate to triquetrous basidiome with acute velutinate margin, regularly cracked pilear surface T. indicus
– Applanate to meagrely ungulate basidiome with obtuse margin and deeply irregularly cracked pilear surface T. tamilnaduensis

Acknowledgements

Malarvizhi Kaliyaperumal and Sugantha Gunaseelan thank EMR-SERB, DST (EMR/2016/003078), Government of India for the financial assistance. MK and GS are grateful to ‘The PCCF’ of Tamil Nadu Forest Department for providing permission (E2/20458/2017), assistance and support during the field visits in Eastern Ghats of Tamil Nadu. MK, SG and KK thank Prof N. Mathivanan, The Director, Centre for Advanced Studies in Botany, University of Madras, Chennai, for providing the laboratory facilities. Samantha Chandranath Karunarathna thanks the National Natural Science Foundation of China (Numbers NSFC 32260004) and the High-Level Talent Recruitment Plan of Yunnan Provinces (“High-End Foreign Experts” programme) for their support. The authors extend their appreciation to the Researchers Supporting Project number (RSP2024R56), King Saud University, Riyadh, Saudi Arabia.

Additional information

Conflict of interest

The authors have declared that no competing interests exist.

Ethical statement

No ethical statement was reported.

Funding

EMR-SERB, DST (EMR/2016/003078), Government of India; National Natural Science Foundation of China (Numbers NSFC 32260004). High-Level Talent Recruitment Plan of Yunnan Provinces (“High-End Foreign Experts” programme) and Researchers Supporting Project number (RSP2024R56), King Saud University, Riyadh, Saudi Arabia.

Author contributions

Conceptualisation: MK, SG, KK; Data Curation: MK, SG, KK, SK,EY, CZ, AME, ST; Formal analysis: MK, EY, SK, CZ, AME, ST; Funding acquisition: SG, MK, SK, EY, CZ, AME, ST; Investigation: MK, SG, KK; Methodology: MK, SG, KK; Project administration: MK; Resources: MK, SG, KK; Software: MK, SK, EY, ST; Supervision: MK, SK; Validation MK, SG, KK, SK; Visualisation: MK; Writing – original draft MK, SG, KK; Writing – review & editing MK, SK, EY, CZ, AME, ST.

Author ORCIDs

Sugantha Gunaseelan https://orcid.org/0000-0001-7089-2292

Kezhocuyi Kezo https://orcid.org/0000-0002-3723-0462

Samantha C. Karunarathna https://orcid.org/0000-0001-7080-0781

Erfu Yang https://orcid.org/0000-0003-2385-6402

Changlin Zhao https://orcid.org/0000-0002-1395-591X

Abdallah M. Elgorban https://orcid.org/0000-0003-3664-7853

Saowaluck Tibpromma https://orcid.org/0000-0002-4706-6547

Malarvizhi Kaliyaperumal https://orcid.org/0000-0002-1218-3778

Data availability

All holotype and paratype collections of the new species are deposited at Madras University Botany Laboratory (MUBL), Centre for Advanced Studies in Botany, University of Madras, Chennai-600 025, Tamil Nadu, India. The sequences generated during this study are deposited in NCBI GenBank. The ITS and nLSU alignment is deposited in TreeBase.

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Supplementary materials

Supplementary material 1 

Pairwise distance matrix, based on nucleotide sequences of four new Tropicoporus spp. and its related species

Sugantha Gunaseelan, Kezhocuyi Kezo, Samantha C. Karunarathna, Erfu Yang, Changlin Zhao, Abdallah M. Elgorban, Saowaluck Tibpromma, Malarvizhi Kaliyaperumal

Data type: xls

Explanation note: Pairwise distance matrix, based on nucleotide sequences of four new Tropicoporus spp. and its related species (Pairwise distances calculations were accomplished using MEGA X v.10.0.2. Distances and standard errors are respectively displayed in the lower-left matrix and the upper-right matrix).

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (132.50 kb)
Supplementary material 2 

Molecular Phylogeny of four new Indian Tropicoporus species inferred from ITS sequences

Sugantha Gunaseelan, Kezhocuyi Kezo, Samantha C. Karunarathna, Erfu Yang, Changlin Zhao, Abdallah M. Elgorban, Saowaluck Tibpromma, Malarvizhi Kaliyaperumal

Data type: jpg

Explanation note: The topology is from Bayesian analysis. Bootstrap values and Bayesian posterior probabilities, equal to or above 60% and 0.90, respectively, are labelled at the nodes. The newly-generated sequences are coloured and bold, and the type specimens are in bold.

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (1.21 MB)
Supplementary material 3 

Molecular Phylogeny of four new Indian Tropicoporus species inferred from nLSU sequences

Sugantha Gunaseelan, Kezhocuyi Kezo, Samantha C. Karunarathna, Erfu Yang, Changlin Zhao, Abdallah M. Elgorban, Saowaluck Tibpromma, Malarvizhi Kaliyaperumal

Data type: jpg

Explanation note: The topology is from Bayesian analysis. Bootstrap values and Bayesian posterior probabilities, equal to or above 60% and 0.90, respectively, are labelled at the nodes. The newly-generated sequences are coloured and bold and the type specimens are in bold.

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Download file (1.22 MB)
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