Wongia bandungensis Chuaseehar., Nuankaew, Somrith. & Boonyuen, sp. nov.
Index Fungorum number: IF 900201; Mycobank number: MB 900201; Facesoffungi number: FoF 15104; Fig. 1
Etymology – The specific epithet “bandungensis” refers to the Ban Dung District, Udon Thani Province, Thailand where the species originated.
Holotype – BBH 49604
Saprobic on submerged twigs in freshwater habitat. Sexual morph: Not observed. Asexual morph: Colonies on natural substratum effuse, scattered, hairy, brown. Mycelium 2–2.5 μm diam, mostly immersed, composed of branched, septate, smooth-walled, pale brown to brown hyphae. Conidiophores 77.5–153.3 × 2.7–4.7 μm (x̄=118.3 × 3.6 μm, n = 40), macronematous, mononematous, solitary, simple, cylindrical, erect, flexuous, 5–9-septate, smooth-walled, dark brown, paler towards the apex. Conidiogenous cells 32.2–114.4 × 2.6–3.6 μm (x̄=71.3 × 3.1 μm, n = 25), holoblastic, polyblastic, sympodial, integrated, terminal, denticulate, subhyaline, with pale brown scar. Conidia 11.3–14×4.3–5.2 μm (x̄=12.6×4.8 μm, n=30), acropleurogenous, solitary, ellipsoidal to oblong-ellipsoidal, tapering and rounded at both ends, 1–2-septate, smooth-walled, hyaline to pale brown. Conidial secession schizolytic.
Culture characteristics – Colonies on PDA reaching 38–39 mm diam after 14 days at 25 °C, velvety, brown with greyish white margins, round, margins entire, soluble pigment absent, exudates absent, reverse dark brown with brownish orange margins.
Material examined – Thailand, Udon Thani Province, Ban Dung District, on submerged twigs of an unidentified plant in a freshwater river, 7 July 2022, S. Phookongchai, isolate FF01118 (BBH 49604, holotype), ex-type, TBRC-BCC 95171; isolate FF01118.01 (BBH 49605, isotype), living culture, TBRC-BCC 95343.
GenBank numbers – TBRC-BCC 95171: ITS=OQ121929, LSU = OQ121947, rpb2= OQ116752, SSU: OQ121938, tef1-α=OQ116761; TBRC-BCC 95343: ITS=OQ121930, LSU = OQ121948, rpb2= OQ116753, SSU: OQ121939, tef1-α=OQ116762.
Notes – Phylogenetic analyses based on the combined ITS, LSU and tef1-α sequence showed that our new species should be classified within Wongia (Fig. 2). Phylogenetically, W. bandungensis is sister to W. suae with strong statical support. However, they can be distinguished mainly by the conidial morphology. The conidia of W. suae are 2–3-septate, clavate to fusiform with rounded at apex and acute at base and smaller (8–11×3–4 μm; Zhang et al. 2023a, b, c, d), while conidia of W. bandungensis are 1–2-septate, ellipsoidal to oblong-ellipsoidal with nonacute base and larger. In culture, W. bandungensis strains exhibited in faster colony growth rate on PDA (38–39 mm diam after 14 days vs. 31 mm diam after 21 days in W. suae; Zhang et al. 2023b). Wongia bandungensis is morphologically similar to W. bambusae in its conidial pigmentation, which is hyaline or colourless. However, W. bambusae differs from W. bandungensis by having longer conidiophores (50–90×2.5–4.0 μm, x̄=75×3.3 μm) with hyaline, more septate conidia (0–3 septa; YU et al. 2024). Wongia bandungensis is newly introduced based on morphological data and DNA sequence analyses.
Figure 1 – Wongia bandungensis (BBH 49604, holotype). a Colonies on natural substrate. b–c Upper and reverse views of culture on PDA after 14 days at 25 °C. d–g Conidiophores, conidiogenous cells and conidia. h–k Conidia. Scale bars: a=100 μm, d, e=20 μm, f–k=10 μm
Figure 2 – Phylogram generated from maximum likelihood analysis (RAxML) of the Papulosaceae based on the combined ITS, LSU and tef1-α sequence data. Nineteen taxa are included in the combined analyses, which comprise 2,256 characters with gaps. Pseudostanjehughesia aquitropica (MFLUCC 16-0569) and P. lignicola (MFLUCC 15-0352) were used as the outgroup. The best scoring RAxML tree with a final likelihood value of − 7766.776319 is presented. The matrix had 567 distinct alignment patterns, with 20.20% of undetermined characters or gaps. The proportion of invariable sites was 0.348999. Estimated base frequencies were as follows: A=0.232003, C=0.263011, G=0.290595, T=0.214390; substitution rates: AC=1.028239, AG=2.023933, AT=1.464845, CG=0.895737, CT=6.942934, GT=1.00000; gamma distribution shape parameter α=0.424774. Bootstrap support values for ML equal to or greater than 70% and BYPP equal to or greater than 0.95 are given near the nodes. T=ex-type strain. The newly generated sequences are indicated in blue bold