Research Article |
Corresponding author: Junaid Khan ( junaid.botany@gmail.com ) Academic editor: Kentaro Hosaka
© 2017 Junaid Khan, Hassan Sher, Arooj Naseer, 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:
Khan J, Sher H, Naseer A, Khalid AN (2017) Descolea quercina (Bolbitiaceae), a new species from moist temperate forests in Pakistan. MycoKeys 27: 65-76. https://doi.org/10.3897/mycokeys.27.14730
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A new species, Descolea quercina, is described and illustrated from Northern parts of Khyber Pakhtunkhwa, Pakistan. It is characterized by medium to large basidiomata, squamose to squamose-granulose hygrophanous pileus, and limoniform, verrucose basidiospores with partly concrescent verrucae. Phylogenetic analyses of nuc rDNA region encompassing the internal transcribed spacers 1 and 2 along with 5.8S rDNA (ITS) and nuc 28S rDNA D1-D2 domains (28S) also confirmed it as a new species. A comparison with similar taxa is provided.
Basidiomycota , ectomycorrhiza, taxonomy
The genus Descolea Singer was based on D. antarctica Singer, which has agaricoid basidiomata with an annulus, thus resembling Rozites or Pholiotina spp. (
Collections were made on routine mycological visits to the moist temperate Quercus dominated mixed forests of Malam Jabba (Swat district) and Toa valley (Shangla district), Khyber Pakhtunkhwa province, Pakistan. Basidiomata were collected following
Microscopic characters are based on free hand sections from fresh and dried specimens mounted in 5% (w/v) aqueous Potassium Hydroxide (KOH) solution. Measurements of anatomical structures are based on calibrated computer based software “PIXIMÈTRE version 5.9” connected to a compound microscope (BOECO, Model: BM120) and visualized through a microscopic camera (MVV 3000). A total of twenty basidiospores, basidia, cystidia and hyphae were measured from all the collections. For measurements; Q is the range of length/width (L/W) ratio of the total measured basidiospores; Qe is the average L/W ratio of all the measured basidiospores; Me is the average L × W of all the measured basidiospores. Surface of the basidiospores was studied both in 5% KOH solution and scanning electron microscopy (SEM).
DNA from herbarium specimens was extracted following the procedure mentioned in
The ITS region of the voucher collections MJ-1590, MJ-1590a and AST33 yielded a 725, 732 and 735 bp fragments respectively. Sequences of all the three specimens were used as a reference to BLAST against GenBank. All the query sequences matched 88% with Descolea phlebophora E. Horak (HQ533035) and D. recedens (Sacc.) Singer (KU523938) from New Zealand. Sequences of other genera, Descomyces Bougher & Castellano, Timgrovea Bougher & Castellano and Setchelliogaster Pouzar, were also downloaded for high similarity with query sequences and used in the subsequent phylogenetic analyses. Hebeloma fastibile (Pers.) P. Kumm (AF325643) and H. circinans (Quél.) Sacc. (JF908041) were selected as outgroup taxa (
The 28S region yielded a 958 bp fragment for MJ-1590 and AST33, while the third collection (MJ-1590a) yielded a noisy sequence which was not included in the final analyses. The query sequences on blast showed 99% similarity with Descolea recedens (Sacc.) Singer (HQ827174), Descolea maculata Bougher (DQ457664) and Descolea gunnii (Berk. ex Massee) E. Horak (AF261523) from USA. Based on high similarity with query sequences, some unknown Descomyces species were also included in the phylogenetic analyses. Hebeloma fastibile (AY033139) and H. affine Smith, Evenson & Mitchel (FJ436324) were used as outgroup taxa.
DNA Sequences were aligned using online webPRANK tool at http://www.ebi.ac.uk/goldman-srv/webprank/ (
The ITS based analysis involved 27 nucleotide sequences. There were a total of 694 characters in the alignment file of which 345 characters were constant, 45 variable characters were parsimony-uninformative while 304 variable characters were parsimony-informative. The tree resulting from the ITS based ML analysis (Fig.
The 28S based analysis involved 17 nucleotide sequences with a total of 941 characters, out of which 867 characters were constant, 16 variable characters were parsimony-uninformative and 58 variable characters were parsimony-informative. The ML phylogram (Fig.
PAKISTAN. Khyber Pakhtunkhwa Province, Swat district, Malam Jabba valley, 1950 m alt., 25 July 2015, Junaid Khan, MJ-1590, (holotype: SWAT000135).
Basidiomata medium to large, pileus convex to convex-campanulate with a broad umbo in young stages, light yellowish brown to deep yellowish brown, surface dry, hygrophanous, squamose to squamose-granulose with striate margin; basidiospores limoniform, coarsely verrucose with partly concrescent verrucae.
Pileus 50–70 mm diameter, convex to convex-campanulate with a broad umbo when young, plane to plano-concave by maturity, light yellowish brown (7.5YR 7/4) to deep yellowish brown (10YR 3/8) with or without olivaceous tinge, surface hygrophanous, squamose to squamose-granulose, scales more or less concentrically arranged, loose, disappearing in age, margin striate; context strong yellowish brown (10YR 5/8), moist, thicker at the center (2–3 mm), color unchanging upon cutting. Lamellae adnexed, close, light grayish brown (7.5YR 6/4) in young specimens, yellowish brown in mature specimens (7.5YR 7/4), lamellar edge even, lamellulae present, mostly 3 in number, rarely single, often crisped at terminals, some lamellae forking near the stipe. Stipe 50–70 × 8–12 mm, central, thickening towards base, light yellowish brown (7.5 YR 7/4) to strong yellowish brown (10YR 4/8) and smooth above the ring , yellowish brown (10YR 5/6) and longitudinally fibrillose below the annulus; annulus membranous, concolorous with the lamellae, strongly striate on the upper surface, smooth to slightly scaly below, margin appendiculate; context fibrous, interior hollow at the center, flesh whitish above the annulus, yellowish brown (10YR 5/6) below, moist. Smell and taste rancid when cut.
Basidiospores (10–) 11.5–13 (–14) × (6.5–) 6.7–8.6 (–9) µm, Q = 1.4–1.7 (–1.9), Me = 12.0 × 7.9 µm, Qe = 1.5, limoniform, with prominent papilla, coarsely verrucose, verrucae partly concrescent, with prominent smooth apiculus, perispore distinct, without germ-pore, plage smooth, rust brown in KOH. Basidia 25–40 × 8–12 µm, clavate, tetra-sterigmated, rarely bi sterigmated, sterigmata 3–5 µm long, with clamp connections at the bases. Cheilocystidia 40–45 × 10–15 µm, broadly clavate to clavate, some with acute apices 4–6 µm long. Pleurocystidia similar to cheilocystidia, lanceolate to clavate, some with sub-acute to sub-capitate apices, appendix longer (6–8 µm) than with cheilocystidia. Pileipellis a hymeniform layer, consisting of broadly clavate, clavate to fusiform elements, 20–25 × 10–20 µm, strongly encrusted with golden brown pigment. Hyphae of the universal veil thin walled, cylindrical, 3–6 µm in diameter, strongly encrusted with golden brown pigment, clamp connections present.
PAKISTAN, Khyber Pakhtunkhwa province, Swat district, Malam Jabba valley, Kishawra village. PAKISTAN Khyber Pakhtunkhwa Province, Shangla district, Toa valley.
Associated with Quercus species. Season July-August
The epithet “quercina” refers to association of this taxon with Quercus species.
The species is very rare and is currently reported from two locations in the districts of Shangla and Swat in the northern areas of Khyber Pakhtunkhwa province, Pakistan.
Pakistan, Khyber Pakhtunkhwa province, Shangla district, Toa valley, 2000 m alt., among decomposing litter under Quercus incana, 15 July 2015, Arooj Naseer, AST33, (LAH35218). Pakistan, Khyber Pakhtunkhwa province, Swat district, Malam Jabba valley, 1900 m alt., on soil under Quercus dilatata Royle, 25 July 2015, Junaid Khan, MJ-1590a, (LAH35219).
Descolea quercina is characterized by medium to large basidiomata, with light yellowish brown to deep yellowish brown color, hygrophanous and squamose to squamose-granulose pileus, light brown to yellowish brown stipe with strongly striated annulus and fibrillose base, and limoniform, coarsely verrucose basidiospores with a smooth apiculus covering the partly concrescent verrucae.
Morphologically, D. quercina and D. pretiosa E. Horak, resemble each other, in particular because of similar sized basidiomata, color, and limoniform basidiospores. However, D. pretiosa differs from D. quercina by its strongly scaly pileus, somewhat larger basidiospores (12–14.5 × 7–8 µm) with isolated warts, and habitat under conifers (
Based on phylogenetic evidence, D. quercina is sister to a clade circumscribing D. maculata, D. gunnii and D. recedens. Descolea maculata also has a pileus with appressed squamulae, similar colored basidiomata, and basidiospores of almost the same size (10–13 × 6–7.5 µm). But D. maculata has a rippled or wrinkled pileus surface and amygdaliform to sublimoniform basidiospores, which are minutely verrucose (
Morphological comparison of Descolea quercina with morphologically similar species.
Characters/ Species | Size of fruiting body | Color | Surface features | Size and shape of basidiospores | Ornamentation | Associated with |
---|---|---|---|---|---|---|
D. quercina sp. nov. | Pileus 50–70mm, stipe 50–70 × 8–12 mm | Light yellowish brown to deep yellowish brown with or without olivaceous tinge | Squamose to squamose-granulose, margin striated | 11.5–13 × 6.7–8.6 µm, Q = 1.5, limoniform | Coarsely verrucose, verrucae partly concrescent | Quercus |
D. flavoannulata (Lj.N. Vassiljeva) E. Horak. | Pileus 50–80 mm, stipe 60–100 × 7–10 mm | Melleous ocher to dark brown | Radially wrinkled, sprinkled with concentrically arranged, small, floccose scales | 12–16 × 8–9 µm , limoniform | Coarsely verrucose | Castanopsis, Larix, Pinus, Quercus |
D. gunnii (Berk. ex Massee) E. Horak | Pileus 10–45 mm, stipe 15–60 × 1.5–7 mm | Dark brown to ochraceus | Densely appressed fibrillose-squamulose, striated at the margin, | 9.5–12 × 6–7 µm, sub–limoniform | Verrucose with smooth mucro | Leptospermum, Nothofagus |
D. pallida E. Horak | Pileus 10–40 mm, stipe 20–60 × 2–5 mm | Yellowish to reddish-brownish | Distinctly slimy, radially wrinkled, striated at the margin | 10–13 × 5–6.5 µm, amygdaliform–limoniform | Isolated minute warts | Nothofagus |
D. phlebophora E. Horak | Pileus 10–30 mm, stipe 30–70 × 2–6 mm, | Reddish brown to liver brown | Deeply wrinkled at the center and radially veined, striate near the margin, veil remnants absent | 8–11.5 × 5–6 µm, amygdaliform | Minutely warted | Nothofagus |
D. pretiosa E. Horak | Pileus 70–85 mm, stipe 75–80 × 11–13 mm | Fuscous with slight olivaceous tinge to date brown when moist, becoming rich brownish ochraceous with olivaceous tinge | Strongly rugulose, with small, floccose, loose scales | 12–14.5 × 7–8 µm, limoniform | Strongly verrucose by isolated warts | Abies, Picea, Pinus, Taxus |
Cortinarius majestaticus (E. Horak) T.P. Andreson & Orlovich | Pileus 30–70 mm, stipe 40–80 × 8–15 mm | Dark brown with a olive-greenish tinge | Slimy, without squamules, margin striated and there wrinkled | 12.5–15 × 7–8 µm, amygdaliform | Strongly warted | Nothofagus |
Descolea quercina is a striking new species associated with Quercus in temperate areas of Pakistan. The ecology and biogeography of this species are particularly significant since most Descolea species associated with Fagaceae are native to the Southern hemisphere (New-Zealand, Australia, South America). The only known Descolea species associated with Quercus or Castanopsis and occurring in the Northern hemisphere are now D. flavoannulata and D. quercina.
The authors are highly thankful to Higher Education Commission of Pakistan (HEC) for their financial support under NRPU project. We are also indebted to Prof. Dr. Ursula Peintner (Leopold Franzens Universität Innsbruck) and Dr. Shah Hussain (Center for Plant Sciences and Biodiversity, University of Swat, Pakistan) for their pre-submission review and technical suggestions for shaping this manuscript.