Bambusicola autumnalis R.R. Liang, S.N. Zhang and Jian K. Liu, 2023

Liang, Rui-Ru, Zhang, Sheng-Nan & Liu, Jian-Kui, 2023, Bambusicola autumnalis sp. nov., a bambusicolous ascomycete from Sichuan province, China, Phytotaxa 601 (3), pp. 203-211 : 208

Bambusicola autumnalis R.R. Liang, S.N. Zhang and Jian K. Liu , sp. nov.

MycoBank: 847551; FIGURE 2 .

Etymology: —The epithet “ autumnalis ” refers to the season “autumn” when the fungus was collected.

Holotype:—HKAS 126508

Saprobic on dead bamboo branches. Sexual morph: Ascostromata solitary to gregarious, rarely scattered, immersed to erumpent, pseudostromatic, visible as bumped areas with cracks and a central black minute papilla, in vertical section conical to subglobose, ostiolate, periphysate, individual locules 190–325 μm high, 215–295 μm diam (x = 280 × 250 µm, n = 10). Peridium 19–43 μm, composed of several layers of thick-walled, brown cells of textura angularis. Hamathecium 1–1.9 μm wide, trabecular pseudoparaphyses, anastomosing, hyaline, remotely septate. Asci 52–102 × 8–17 µm (x = 71 × 12 µm, n = 20), 8-spored, bitunicate, fissitunicate, long cylindric-clavate, shortly pedicellate, apically rounded with a minute ocular chamber. Ascospores 22–30 × 4.5–7 µm (x = 27 × 5 µm, n = 30), overlapping bi-seriate or multi-seriate, fusiform, 1-septate, constricted at the septum, guttulate, smooth-walled, surrounded by a thin, inconspicuous mucilaginous sheath. Asexual morph: Undetermined.

Culture characteristics:—Colonies on PDA reaching 28–32 mm after 4 weeks incubated at 25 °C in dark, circular, dry, mycelium velvety, milky white to pale yellow, reverse yellow to light brown.

Material examined:— CHINA, Sichuan province, Chengdu city, Chengdu Botanical Garden , 30°76.48’ N, 104°13.03’ E, 516 m elevation, on dead branches of bamboo in a terrestrial environment, 21 Nov. 2022, R.R. Liang, (HKAS 126508, holotype), ex-holotype living culture CGMCC 3.24280 ; ibid., HUEST 23.0001, isotype, ex-isotype living culture UESTCC 23.0001 .

Notes:—Multi-gene phylogenetic analysis showed that our isolates belong to Bambusicola and are closely related to B. guttulata ( FIGURE 1 ). However, it is not able to compare their morphology as the latter species only represented by a coelomycetous asexual morph. Nevertheless, Bambusicola autumnalis differs from B. guttulata in their nucleotide sequences, viz. SSU (6/950), ITS (44/450), LSU (17/800), RPB2 (73/993) and TEF1-α (49/959), respectively. Morphologically, Bambusicola autumnalis resembles B. loculata in having stromatic ascomata, 8-spored, cylindric asci, and narrowly fusiform, 1-septate ascospores surrounded by an inconspicuous sheath ( Dai et al. 2015). However, they have different dimensions of asci (52–102 × 8–17 μm vs. 80–105 × 8–13 μm) and ascospores (22–30 × 4.5–7 µm vs. 22–26.5 × 5–6), and the bumped ascostromata with cracks of B. autumnalis also differs from B. loculata . Moreover, the two species are phylogenetically distinct ( FIGURE 1 ).

Figures

FIGURE 1. Maximum likelihood (RAxML) tree based on a combined sequence dataset (SSU, ITS, LSU, RPB2 and TEF1-α) of taxa from Bambusicolaceae. Bootstrap values for ML and MP equal or greater than 75%, and BI posterior probabilities equal or greater than 0.95 are indicated. New isolated strains are indicated in red and ex-type strains are indicated in bold.

FIGURE 2. Bambusicola autumnalis (HKAS 126508, holotype) a–cAscostromata on host substrate. d, e Vertical section of Ascostroma, which shows pseudostromatic structure. f Peridium. g Ostiole. h Trabeculate pseudoparaphyses. i Germinating ascospore. j Ascospore stained in India ink which shows a gelatinous sheath. k–o Asci. p–t Ascospores. u, v Colony on PDA, above (u) and below (v). Scale bars: d =100 μm, e = 50 μm, f, g, i = 20 μm, h, j, k–t = 10 μm.