Leccinum anastasiae V. Vlasenko, 2023

Vlasenko, Vyacheslav A., 2023, A new Leccinum species from the Altai Mountains, Phytotaxa 625 (2), pp. 191-200 : 194-197

Leccinum anastasiae V. Vlasenko , sp. nov. Fig. 1 .

MycoBank: MB 844740.

Type: — RUSSIA. The Republic of Altai , near Dzhazator (Belyashi) village, a habitat with solitary Larix Mill. and Salix L. trees on the border with a steppe meadow and a bog in the river’s oxbow, on soil under Salix bebbiana Sarg. , 49.6914° N, 87.4344° E, 1569 m., 21 August 2019, V.A. Vlasenko and A.V. Vlasenko (holotype NSK 1014999 ).

Etymology: —Named after mycologist Anastasia Vlasenko.

Description: —Basidiomata is medium-sized. Pileus is up to 4 cm in diam., convex, up to 1.4 cm thick, lacking a sterile margin; surface is dry, glabrous, rugulose, dark cream with a light marble pattern; context is thin, 1 mm thick, in the center of the pileus is up to 1 cm thick, white, and does not change color when bruised but may darken slightly; bright colors absent. Hymenophore is poroid; pores are angular, 0.3–0.6 mm in diam., concolorous, light cream, staining cinnamon brown if bruised and with age; tubes adnexed to deeply depressed around the stipe, up to 1.3 cm in length, tube walls are 0.05 mm thick, white-greyish-cream when young to pale cinnamon-brown with age. Stipe is 5 cm long, 0.6–1.0 cm broad, central, cylindrical, slightly curved, dense, fragile; surface dry, white, scabrous, scales are white at first, becoming pale to pale-cream, staining fuscous if bruised; context is white, light cream with age; basal mycelium is white. No distinctive odour. Basidiospores are 5.4–6.90 × 14.2–23.60 μm, Q min = 2.62, Q max = 3.42, Qm = 2.96, spindle-shaped to elongate-ellipsoid, creamy brown with greenish-brown protoplast in KOH, smooth. Basidia are 6.5–11 × 20–28.5 μm, clavate, thin-walled, 2–4-spored, hyaline in KOH; sterigmata are 4–5 μm in length. Hymenophoral trama is boletoid, hyphae are subcylindrical, 3–7 μm wide, and hyaline. Cheilo- and pleurocystidia are 7–12 × 18–30 μm, spindle-shaped to fusiform, thin-walled, hyaline. Pileipellis is a trichoderm composed of filamentous hyphae 3.5–10 μm wide, thin-walled, hyaline. Pileus trama is composed of hyphae 2.5–11 μm wide, thin-walled, hyaline. Stipitipellis is composed of hyphae 2–8 μm wide, thin-walled, hyaline. Caulocystidia are 9–10 × 18–28 μm, spindle-shaped to fusiform, thin-walled, hyaline. Stipe trama is composed of hyphae 3–10 μm wide, thin-walled, hyaline. Clamp connections are absent in all tissues.

Additional specimen examined: — RUSSIA. The Republic of Altai, near Dzhazator (Belyashi) village, the right bank of the Argut River , swampy habitat with Salix L . trees by the river, on soil, 49.7244° N, 87.3941° E, 1601 m., 23 August 2019, A. V . Vlasenko (paratype NSK 1014981 ) .

Habitat: —Scattered on the ground under Salix bebbiana Sarg. , near bogs in the river valleys between mountain ranges.

Distribution: —Southeast Altai (Kosh-Agach district of the Republic of Altai).

GenBank accession numbers: ITS: ON524838, LSU: ON514264; EF-1α: OR758905; RPB2: OR758904.

Comments: —The new species Leccinum anastasiae does not have orange and red tints in the cap color. Based on this, it is easy to differentiate it from other species of the genus, which have brightly colored fruiting bodies. The cap surface of Leccinum anastasiae is creamy brown, and the surface of its pores becomes tobacco-like over time. It differs from the closely related species, Leccinum schistophilum and L. snellii A.H. Sm., Thiers et Watling (1967: 120) , by the absence of pink coloration in the upper and blue-green coloration in the lower part of the stipe when bruised.

The ITS1 nrDNA region in Leccinum species contains many tandem repeats ( Den Bakker et al. 2004). The analysis of our aligned dataset showed the presence of 19 regions with “TATTGAAAA” repeats. The maximum number of such repeats in some sequences is up to 11 in Leccinum holopus . In addition, there were 15 regions with “CTAATAGAAA” repeats, with a maximum number of repeats up to eight, also in Leccinum holopus . The presence of such mini satellites negatively affects the phylogenetic reconstruction for the genus. Therefore, we performed a phylogenetic analysis of the ITS1-5.8S-ITS2 nrDNA region, excluding mini satellites from the sequences. Introns were also excluded from the sequences of all genes.

The ML analysis based on the ITS1-5.8S-ITS2 nrDNA region showed that the new species is closest to Leccinum schistophilum ( Fig. 2 ). The genetic distance of the “ Leccinum anastasiae ” branch on the ITS tree is 0.022, with 97% bootstrap support.

In addition, the ML analysis based on the 28S+ EF-1α + RPB2 DNA regions confirmed that the new species is closest to Leccinum schistophilum ( Fig. 3 ). The genetic distance of the “ Leccinum anastasiae ” branch on the tree is 0.007, with 87% bootstrap support.

Despite some inconsistency in the topology of our ITS1-5.8S-ITS2 and 28S+ EF-1α + RPB2 trees, the new species of Leccinum anastasiae had the most similarity with L. schistophilum . Based on that, we performed a separate comparison of the sequences of these two species. It turned out studied sequences ITS1-5.8S-ITS2 and parts of the 28S, EF-1α and RPB2 regions was quite variable, which allows us to declare the independence of these species.

Substrate and geographic factors are also crucial for species diagnostics. Leccinum holopus , L. schistophilum and L. snellii growing on swamps form symbiotic associations with Betula L. (1753: 982) spp. The new species Leccinum anastasiae is associated with a unique symbiont, Salix bebbiana .

Figures

FIGURE 1. Leccinum anastasiae (holotype NSK 1014999). A. Typical species habitat near Dzhazator village. B-C. Spores (SEM). D. Spores (CM). E. Pileus surface (DM). F-G. Fresh fruiting bodies in nature. H. Hymenophore (DM). Scale bars: B = 20 μm, C = 2 μm, D = 20 μm, E = 1 mm, F–G = 1 cm, H = 1 mm.

FIGURE 2. The maximum likelihood tree based on ITS 1-5.8 S-ITS 2 DNA sequences shows the phylogenetic relationships between the new species, Leccinum anastasiae, and other closely related Leccinum species. BS values with support over 50% and Bayesian Posterior Probabilities are shown.

FIGURE 3. The maximum likelihood tree based on LSU+ EF-1α+RPB2 DNA sequences shows the phylogenetic relationships between the new species, Leccinum anastasiae, and other closely related Leccinum species. BS values with support over 50% and Bayesian Posterior Probabilities are shown.