Arcopilus albae Boonmee, Mapook & Phukhams

Juxu, Rong, Phukhamsakda, Chayanard & Boonmee, Saranyaphat, 2024, Identification of a new species and three new records of Chaetomiaceae associated with commercial herbal teas in northern Thailand, Phytotaxa 653 (2), pp. 134-154 : 141-143

Arcopilus albae Boonmee, Mapook & Phukhams , sp. nov. ( Fig. 2 )

Index Fungorum number: IF902098, Facesofungi number: FoF15766

Etymology:—The specific epithet “ albae ” refers to the host species of the substrate from which the fungus was isolated. Etymology:—MFLU 24–0081

Culture characteristics:—Colonies growing on PDA, reaching 3–4 cm diam., in 2 weeks at 25 °C in the dark condition, slightly fluffy, surface smooth, circular, radially striate with entire edge, white to yellowish mycelium, with dark orange to red pigmented in medium within 2 weeks. Mycelium superficial, hyaline, branched, septate, smooth-walled. Ascomata produced in culture within 4–6 weeks as red spots.

Sexual morph on PDA culture: Ascomata 87–134 µm high × 83–144 µm diam., superficial, uniloculate, solitary, globose, sometimes subglobose to ovate, red to brownish-red in reflected light due to ascomatal hairs, covered by dense hairs, ostiole. Peridium composed of brown cells of textura angulris to subglobosa, membranaceous, thin-walled, spare paraphyses. Terminal hairs 2–3.5 µm diam. near the base, apically incurved, circinate to coiled at the apex, unbranched, orange to bright red pigmented throughout the hairs, coarsely verrucose-walled, coiled at the apex septate, verrucose-walled. Lateral hairs 2.5–4 µm diam., slightly flexuous or recurved, tapering towards the apex. Asci 24–30 × 10–14 µm (x = 24.5 × 12 µm, n = 10), 8-spored, fasciculate, unitunicate, ellipsoid to obovoid, slightly clavate, sessile, apically rounded, thin-walled and quickly evanescent. Ascospores 7–9 × 5–6 µm (x = 7.5 × 5 µm, n = 10), overlapping 2-seriate, slightly reniform or semicircular, broad ellipsoidal fusiform to ovate, hyaline when immature, olivaceous green to dark brown at maturity, with one apical germ pore, aseptate, guttulate, smooth-walled. Asexual morph: Undetermined.

Material examined:— THAILAND, Chiang Rai Province, Mae Fah Luang District, Doi Mae Salong market , mulberry leaf tea ( Morus alba , Moraceae ), 22 February 2023, Saranyaphat Boonmee, HBT25A ( MFLU 24–0081 , dried culture, holotype), ex-type living culture MFLUCC 24–0064 .

Notes:— Arcopilus albae is described in this study as a new species, and it shares similar morphological characters of the colony with excreted pigmented in PDA medium, uniloculate, subglobose ascomata, surrounded by orange to brownish-red ascomatal hairs with coiled at the apex and reniform or semicircular, broad ellipsoidal fusiform ascospores with the type species Ar. cupreus and Ar. tangerinicapillus ( Ames 1949, Wang et al. 2016a, Raza et al. 2019). Culture of Ar. albae also diffused red pigment in PDA medium as well as produced a dark red ascomatal wall resembling Ar. cupreus and Ar. tangerinicapillus ( Fig. 2 ). Arcopilus albae differs from these species in having shorter ascospores (7–9 × 5–6 µm), whereas Ar. cupreus (8.5–11.5 × 5–5.5 µm) and Ar. tangerinicapillus (9.5–12.5 × 4.5–7 µm) have longer ascospores. Phylogenetic analysis based on combined ITS, LSU, RPB2 and TUB2 sequence data indicated that Ar. albae forms a distinct lineage basal to Ar. cupreus and Ar. tangerinicapillus clade with 99% ML, 1.00 PP statistical support ( Fig. 1 ). In pairwise nucleotide comparisons of Ar. albae (MFLUCC 24–0064) with the represent type strain Ar. cupreus (CBS 560.80), there is a nucleotide discrepancy of 0.17% (1 out of 567) in ITS, while LSU has no base pair difference. However, in the protein-coding region of TUB2, the nucleotide difference was 1.83% (13 out of 710). A comparison of Ar. albae with the type strain of Ar. tangerinicapillus (CGMCC 3.19326), there is a nucleotide difference of 0.35%, 2 gaps (2 out of 567) in ITS and LSU has no base pair difference, while in the protein-coding region of TUB2 was 1.97% (14 out of 710) difference. Unfortunately, we were unable to obtain RPB2 sequence data for Ar. albae . However, we illustrated and described Ar. albae based on the evidence of phylogeny and nucleotide difference in the TUB2 sequences as a new species.

Figures

FIGURE 1. Phylogram generated from RAxML analysis based on combined ITS, LSU, RPB2, and TUB2 sequence data of Arcopilus taxa. Collariella bostrychodes (CBS 163.73) and Co. carteri (CBS 128.85T) are selected as the outgroup taxa Bootstrap support values. for ML values equal to or>70% and PP values equal to or>0.95 are shown as ML/PP above the nodes. The newly generated sequence in this study is in blue. Type strains are indicated in bold.

FIGURE 2. Arcopilus albae (MFLUCC 24–0064, ex-type culture). a Mulberry leaf tea sample. b, c Culture colony grown on PDA from the surface and reverse after one month. d Top view of ascomata covered by elongate red-brown hairs. e, f Ascomata with lateral hairs mounted in water. g Close-up of terminal hairs with red pigmented coarsely verrucose-walled and coiled at the apex. h Peridium. i Asci. j Ascospores with an apical germ pore. Scale bars: d = 200 µm, e, f = 100 µm, g, j = 10 µm, h = 5 µm, i = 20 µm.