Distoseptispora suae H.W. Shen & Z.L. Luo, 2024

Shen, Hong-Wei, Bao, Dan-Feng, Boonmee, Saranyaphat, Lu, Yong-Zhong, Su, Xi-Jun, Li, Yun-Xia & Luo, Zong-Long, 2024, Diversity of Distoseptispora (Distoseptisporaceae) taxa on submerged decaying wood from the Red River in Yunnan, China, MycoKeys 102, pp. 1-28 : 1

Distoseptispora suae H.W. Shen & Z.L. Luo sp. nov.

Figs 6 , 7

Etymology.

“suae” (Lat.) in memory of the Chinese mycologist Prof. Hong-Yan Su (4 April 1967-3 May 2022), who kindly helped the authors in many ways.

Description.

Saprobic on submerged decaying wood in a freshwater stream. Anamorph: Colonies on wood effuse, brown, solitary or in small group. Mycelium immersed, septate, brown hyphae, smooth-walled. Conidiophores (21-)25-41(-53) × 4-5 µm (x̄ = 33 × 5 µm, n = 20), macronematous, mononematous, solitary or in groups, erect, straight or slightly flexuous, cylindrical, 1-3-septate, brown, unbranched, smooth-walled. Conidiogenous cells (11-)13-15(-16) × 5-6 µm (x̄ = 14 × 5 µm, n = 20), monoblastic, terminal, determinate, subcylindrical, brown, smooth-walled. Conidia (77-)81-101(-109) × 8-10 µm (x̄ = 91 × 9 µm, n = 30), acrogenous, solitary, obclavate to rostrate, truncate at base, tapering towards the apex, straight or slightly curved, bent at the second or third cell at the base, brown to dark brown, 3-12-euseptate, guttulate, verrucose, thin-walled. Teleomorph: Undetermined.

Culture characteristics.

Conidia germinating on PDA within 12 hrs and germ tubes produced from the apex. Colonies growing on PDA reaching 4-5 cm in one month at 26 °C in the dark, with dense, velvety, brown to dark brown mycelium from above; dark brown from below. Sporulation on PDA after two months, Mycelium hyaline to brown, septate, branched, smooth-walled. Conidiophores (15-)16-56(-110) × 4-6 µm (x̄ = 36 × 5 µm, n = 30), usually form at the end of the hyphae, cylindrical, straight or slightly curved, yellowish brown to olivaceous-brown, septate. Conidiogenous cells (9-)11-14(-16) × 4-5 µm (x̄ = 12 × 5 µm, n = 30) monoblastic, terminal, determinate, cylindrical, brown, sometimes reduce conidiophores. Conidia (31-)47-90(-124) × 6-8 µm (x̄ = 68 × 7 µm, n = 40) acrogenous, obclavate, elongated, truncate at base, straight or slightly curved, brown, euseptate, thin-wall, sometimes with a gelatinous sheath around the septum (Fig. 7 ).

Material examined.

China, Yunnan Province, Yuxi City, Xinping Yi and Dai Autonomous County, Yuanjiang River , 24°02′16"N, 101°34′05" E, on submerged decaying branches in a freshwater stream, 22 February 2022, H.W. Shen & Q.X. Yang YJ 14-35-2 (HKAS: 125819, holotype, ex-type, CGMCC3.24262 = KUNCC 22-12476) .

Notes.

Distoseptispora suae clusters with D. hyalina (MFLU 21-0137) with 100% ML/1.00 PP support whereas D. yunnanensis (MFLUCC 20-0153) state in a basal lineage (Fig. 1 ). A comparison of the LSU, ITS, tef 1-α and rpb 2 nucleotide bases between D. suae and D. hyalina revealed differences of 8 bp (8/832, including one gap), 11 bp (11/540, including 3 gaps), 21 bp (21/934), and 54 bp (54/1087) sequence similarity, respectively. Morphologically, D. suae resembles other species in the genus with its euseptate structure, characterized by acrogenous, solitary, obclavate to rostrate conidia. D. hyalina , D. suae and D. yunnanensis cluster in a stable lineage (Fig. 1 ). Since only teleomorphs were found in D. hyalina ( Yang et al. 2021), and only anamorphs were found in D. suae (this study), the morphological characteristics of D. suae and D. yunnanensis were compared here. D. suae can be distinguished from D. yunnanensis by its shorter conidiophores (25-41(-53) µm vs. 131-175 µm) and guttulate, verrucose conidia ( Li et al. 2021). Based on phylogenetic analysis and morphological evidence, following the guidelines of Jeewon and Hyde (2016), we therefore introduce D. suae as a new species.

Figures

Figure 1. Maximum likelihood (ML) tree is based on combined LSU, ITS, tef 1 - α and rpb 2 sequence data. Bootstrap support values with a ML greater than 65 % and Bayesian posterior probabilities (PP) greater than 0.95 are given above the nodes, shown as " ML / PP ". The tree is rooted to Aquapteridospora fusiformis (MFLUCC 18 - 1606) and A. lignicola (MFLUCC 15 - 0377). New species are indicated in blue and type strains are in bold.

Figure 6. Distoseptispora suae (HKAS 125819, holotype) a, b colonies on woody substrates c-e conidiophores and conidiogenous cells f-k conidia l germinated conidium m culture on PDA. Scale bars: 10 μm (c-l).

Figure 7. Distoseptispora suae (ex-type culture KUNCC 22 - 12476) a culture on PDA, obverse (left) and reverse (right) b, c colonies on PDA d mycelium from PDA e mycelium, conidiophores and conidia f conidiophore g-j conidiophores with conidia (Arrow in i, j indicate the gelatinous sheath) k conidia. Scale bars: 10 μm (d); 40 μm (e); 20 μm (f-k).