Research Article |
Corresponding author: Ammara Sattar ( ammarasattar81@gmail.com ) Academic editor: Olivier Raspé
© 2020 Munazza Kiran, Ammara Sattar, Khushbakht Zamir, Danny Haelewaters, Abdul Nasir Khalid.
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:
Kiran M, Sattar A, Zamir K, Haelewaters D, Nasir Khalid A (2020) Additions to the genus Chroogomphus (Boletales, Gomphidiaceae) from Pakistan. MycoKeys 66: 23-38. https://doi.org/10.3897/mycokeys.66.38659
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With only three published reports, the genus Chroogomphus (Boletales, Gomphidiaceae) is poorly studied in Pakistan. During recent sampling events in Khyber Pakhtunkhawa province, Pakistan, several collections of Chroogomphus were made, representing undescribed taxa. Based on morphological and molecular data, two new species are described: Chroogomphus pakistanicus and C. pruinosus. We present a description and illustrations for both taxa. A molecular phylogenetic reconstruction, based on the internal transcribed spacer (ITS1–5.8S–ITS2) barcode region, shows that C. pakistanicus and C. pruinosus are placed in two different subgenera of Chroogomphus (subg. Chroogomphus and subg. Siccigomphus, respectively).
2 new taxa, Basidiomycota, Boletales, coniferous forests, macrofungi, phylogeny, taxonomy
Chroogomphus (Singer) Mill. was initially recognised as a sub-genus of Gomphidius Fr. (Singer 1948). It was
The genus is currently divided into three subgenera – Chroogomphus, Floccigomphus (Imai) Niskanen, Scambler, & Liimat. and Siccigomphus Niskanen, Scambler, & Liimat. (
Chroogomphus species are economically very important because of their ectomycorrhizal association with pines and applications as drugs and food (
Specimens were collected from the Kumrat valley (35°32'N, 72°13'E,
Macro-morphological characters of fresh basidiomata were recorded and colour codes were assigned using
Genomic DNA was extracted from dried tissue employing a modified CTAB protocol (
We constructed an ITS dataset of our newly generated sequences along with closely related sequences that were downloaded from GenBank (
The ITS1, 5.8S and ITS2 loci were extracted from the aligned ITS dataset, allowing the selection of substitution models for each partition. Models were selected using ModelFinder (
A Bayesian Inference (BI) phylogeny was estimated using BEAST version 1.8.4 (Drummond et al. 2012) with an uncorrelated lognormal relaxed clock, allowing for evolutionary rates to vary across branches. We selected a Birth-Death Incomplete Sampling speciation model (Stadler 2009) tree prior and appropriate substitution models as determined by jModelTest2 (Darriba et al. 2012) under AICc. Models were TrNef+G (ITS1, -lnL = 2028.8929), JC (5.8S, -lnL = 320.6928) and TPM3+G (ITS2, -lnL = 1905.6932). Four independent runs were performed from a random starting tree for 40 million generations with a sampling frequency of 4000. The analyses were run from the BEAST on XSEDE tool on the Cipres Science Gateway (Miller et al. 2010). Resulting log files were entered in Tracer (Rambaut et al. 2014) to check trace plots and burn-in values. Effective sample sizes were well over 200 for all sampled parameters for each run and so we selected a standard burn-in of 10%. After the removal of 10% of each run as burn-in, log files and trees files were combined in LogCombiner. TreeAnnotator was used to generate consensus trees (with 0% burn-in) and to infer the Maximum Clade Credibility tree.
Final phylogenetic reconstructions with ML bootstrap values (BS) and BI posterior probabilities (pp) were visualised in FigTree v1.4.3 (http://tree.bio.ed.ac.uk/software/figtree/) and edited in Adobe Illustrator version 23.0.6 (San Jose, California).
Amplification of the ITS from three basidiomata of C. pruinosus resulted in 670 bp sequences (GenBank accession numbers MK509768, MK509769 and MK509770). All of these sequences showed 97% similarity to C. roseolus (LT576117, Pakistan) with 100% query coverage. The ITS sequences obtained from two basidiomata of C. pakistanicus (MK509771, MK509772) were 650 bp in length and showed 98% similarity to C. filiformis Yan C. Li & Zhu L. Yang (EU706324, China) with 95% query coverage.
The ITS1–5.8S–ITS2 dataset included a total of 768 characters for 84 sequences including Gomphidius spp. as outgroup taxa (Suppl. material
Differs from Chroogomphus filiformis by the pileus ranging in colour from greyish-yellow brown to dark bluish-grey to orange and by the absence of a pinkish mycelium at the base of the stipe.
Holotype : Pakistan, Khyber Pakhtunkhwa province, district Dir (Upper), Kumrat valley, 35°32'N, 72°13'E, 2400 m a.s.l., gregarious on forest floor, 20 Aug 2016, M. Kiran & A.N. Khalid, KM82 (LAH35889), GenBank accession number MK509771 (ITS). Paratype: ibid., KM83 (LAH35890), GenBank accession number MK509772 (ITS).
Referring to the country where the type collections were collected.
On forest floor under mixed conifers.
Basidiomata small to medium-sized. Pileus 2–5 cm in diameter, secotioid when young, expanding broadly-parabolic to hemispherical towards maturity, radially fibrillose, ranging in colour from greyish-yellow brown (2.5Y,5/2) to dark bluish-grey (5BG,4/1) to orange (5YR,6/6), surface shiny or glistening, smooth, margin inrolled initially becoming straight to slightly seriate when mature. Lamellae adnate to slightly decurrent, distant, regular, concolorous to pileus, smooth, entire, lamellulae in two tiers, alternating with lamellae, short. Stipe 3–5.5 × 1 cm, central, more or less equal or sometimes enlarged at base, orange (5YR7/8) to reddish-brown (2.5YR4/8), pruinose to fibrillose to squamulose, with pinkish-white mycelium at stipe base, universal and partial veil absent. Odour and taste not recorded.
Basidiospores [60/3/2], (15–)16–19.5(–20.5) × (5.5–)6–7.5(–8) µm, avl × avw = 17.5 × 6.6 µm, Q = (2.1–)2.2–3(–3.5) µm, avQ = 2.56±0.33 µm, oblong to elongate, mono-guttulate to multi-guttulate, pale brown in KOH, apiculus prominent, smooth, dextrinoid. Basidia 30–50 × 8–10.5 µm, avl × avw = 40 × 9 µm, hyaline to pale yellow in KOH, clavate to club–shaped. Lamellar trama yellowish hyphae in KOH, 5–11 µm, with brownish encrustations, inamyloid and non-dextrenoid. Pleurocystidia 75–107 × 17.5–25.5 µm, avl × avw = 91 × 43 µm, clavate to sometimes slightly utriform, pale brown to brown in KOH, encrusted, inamyloid. Cheilocystidia similar to pleurocystidia. Pileipellis a cutis, pale yellow to brownish KOH, 4–6 µm wide, amyloid, septate, clamped. Pileal trama composed of amyloid encrusted hyphae, 4–18 µm, yellowish in KOH. Stipitipellis a cutis of 3–9.5 µm wide, pale yellow to pale brown KOH, cylindrical, parallel, septate amyloid hyphae present at the base. Clamp connection present in all tissues.
Chroogomphus pakistanicus can be easily distinguished from the other members in the genus by the unique bluish-grey colour of its pileus. The phylogenetically closest relative, C. filiformis, (Figure
Differs from Chroogomphus roseolus by the pileal trama that is inamyloid in Melzer’s reagent and by the presence of pileocystidia and caulocystidia.
Holotype : Pakistan, Khyber Pakhtunkhwa province, district Upper Dir, Kumrat valley, 35°32'N, 72°13'E, 2400 m a.s.l., solitary or sub-gregarious on moisture rich loamy soil, 20 Aug. 2016, M. Kiran & A.N. Khalid, KM86 (LAH35886), GenBank accession MK509768 (ITS). Paratypes: ibid., KM85 (LAH35888), GenBank accession number MK509769 (ITS); ibid., FS12 (LAH35887), GenBank accession number MK509770 (ITS).
Referring to the pruinose surface of pileus and stipe.
On forest floor under mixed conifers.
Basidiomata small to medium-sized, Pileus 0.5–3.5 cm in diameter, hemispherical, obtusely conic when young, expanding convex to broadly convex with maturity, margin inrolled initially becoming decurved, surface rough, pruinose, yellowish-orange to reddish-brown (7.5YR8/8–2.5YR4/8). Lamellae decurrent, sub-distant to distant, regular, broad up to 0.5 cm, forked near margin, light yellowish-orange (10YR,8/3), gill margins even, smooth, lamellulae in 2 tiers, alternating with lamellae. Stipe up to 4 cm long, central, pruinose, yellowish-orange to reddish-brown (7.5YR8/8–2.5YR4/8) in colour, rough, with tawny basal mycelium, more or less equal to broader towards base, universal and partial veil absent. Odour and taste not recorded.
Basidiospores [60/3/3], (11–)15–19(–21) × (4–)4.5–8(–8.5) µm, avl × avw = 16.5 × 6.5 µm, Q = (2.2–)2.3–3.4(–3.5), avQ = 2.64±0.43 µm, pale yellow to pale grey-brown in KOH, elongate to somewhat ellipsoid, slightly thick–walled, apiculate, dextrinoid, mostly mono-guttulate, germ pore absent. Basidia 37–53 × 7–13 µm, avl × avw = 41 × 11 µm, hyaline in 5% KOH, clavate, clamped at base, four-spored. Lamellar trama made up of hyphae, 3–6 µm, yellowish in KOH, encrusted, hyphae inamyloid with no or slightly amyloid encrustations, non-dextrenoid. Pleurocystidia 87–112 × 15–23 µm, avl × avw = 93 × 18 µm, hyaline with pale yellow walls in KOH, abundant, encrusted. Cheilocystidia similar to pleurocystidia but slightly smaller. Pileipellis an ixocutis of radially arranged hyphae, 10–12 µm in diameter, yellow to pale brown in KOH, inamyloid, with thin encrusted walls, cylindrical, septate, clamped. Pileocystidia 47–65 × 15–22 µm (avl × avw = 55 × 20 µm), similar to hymenial cystidia, pale yellow to pale brown in KOH. Pileal trama composed of yellowish hyphae with brownish encrustation in KOH, 12–20 µm, inamyloid and non-dextrenoid. Stipitipellis 6–12 µm, pale brown in KOH, inamyloid, straight, cylindrical, smooth and parallel. Caulocystidia 37–111.5 × 7–13.6 µm (avl × avw = 76.5 × 10.25 µm), rare, similar to hymenial cystidia.
Chroogomphus pruinosus differs from all other members of the genus in having pileocystidia. This new species is phylogenetically most closely related to C. roseolus, a species that has been reported from China and Pakistan (
1 | Pileipellis hyphae non-gelatinised | 2 |
– | Pileipellis hyphae gelatinised | 3 Subgenus Chroogomphus |
2 | Lamellar trama amyloid, cystidia thick-walled | Subgenus Floccigomphus |
– | Lamellar trama inamyloid, cystidia thin-walled | 4 Subgenus Siccigomphus |
3 | Pileus umbonate, ochraceous to vinaceous, Pileipellis hyphae inamyloid | Chroogomphus rutilus |
– | Pileus broadly parabolic, bluish-grey to orange, Pileipellis hyphae amyloid | Chroogomphus pakistanicus |
4 | Pileal trama amyloid, pileocystidia and caulocystidia absent | Chroogomphus roseolus |
– | Pileal trama inamyloid, pileocystidia and caulocystidia present | Chroogomphus pruinosus |
Many taxa of fungi have recently been described using an integrative approach, combining morphology, DNA data and ecology (e.g.
Our phylogenetic tree, obtained from ML and BI analyses (Figure
The subgenera in our phylogenetic analyses are also supported morphologically. Members of clade II fall in subg. Siccigomphus found all over the Northern Hemisphere and are similar in having comparatively smaller basidiospores and inamyloid lamellar trama. They can be distinguished from the members of clade III, which belong to subg. Chroogomphus and have a narrow pileipellis and shiny pileus surface and distributed throughout Eurasia, but not in North America. Clade I represents subg. Floccigomphus, with members that are found in North America and Asia, but not in Europe and recognised by non-gelatinised pileipellis hyphae and amyloid lamellar trama.
Based on the distinct and well-supported molecular phylogenetic placement of our Pakistani collections in combination with morphological differences with their closest described relatives, we confirm that they represent two new species in the genus Chroogomphus.
The authors thank María Paz Martín Esteban (Real Jardín Botanico, Departamento de Micología, Madrid, Spain) for support and critically reviewing early drafts of this manuscript, and Zhu L. Yang (Chinese Academy of Sciences, Kunming Institute of Botany, Key Laboratory of Biodiversity and Biogeography, Kunming, China) for providing helpful suggestions. Sincere thanks to the Higher Education Commission (HEC) in Pakistan for providing partial financial support under the National Research Program for Universities (NRPU: 203383/NRPU/R&D/HEC/14/184).
Table S1. Taxa used in molecular phylogenetic analysis with voucher, country, and ITS GenBank accession number
Data type: GenBank accession numbers and associated metadata