Parabambusicola yunnanensis L.S. Han & D.Q. Dai, 2023

Han, Li-Su, Dai, Dong-Qin, Du, Tian-Ye, Wijayawardene, Nalin N., Promputtha, Itthayakorn, Bhat, D. Jayarama & Gao, Yong, 2023, Taxonomy and phylogenetic studies revealed Parabambusicola yunnanensis sp. nov. (Parabambusicolaceae, Pleosporales) on bamboo from Yunnan, China, Phytotaxa 589 (3), pp. 245-258 : 250-253

Parabambusicola yunnanensis L.S. Han & D.Q. Dai , sp. nov.

( Figure 2 )

Index Fungorum number: IF559989; Facesoffungi number: FoF 12952

Etymology: Named after the Yunnan Province of China, where the fungus was first discovered.

Holotype: GMB1291

Saprobic on dead culm of bamboo. Sexual morph: Ascomata 300–500 μm diam., 190–280 μm high, gregarious, clustered in groups, immersed under a black area, raised with black subglobose area on host surface, hemispherical or conical with a flattened base in cross-section, uniloculate, with a central ostiole (with 50–90 μm diam., 55–100 μm long); forming a white floccose ascospore masses on surface of the ascomata. Peridium 5–20 μm thick, comprising host and fungal tissues, poorly developed at the base, fusing with host, 8–15 µm wide above, composed of hyaline cells of textura angularis, and palisade-like cells at the rims. Hamathecium comprising numerous, 1–2.5 μm wide, filamentous or slenderly cylindrical, septate, branched pseudoparaphyses. Asci 130–180 μm × 20–30 μm (x̄ =153 × 25 μm, n=20), bitunicate, fissitunicate, 8-spored, cylindric-clavate to clavate, straight to slightly curved, subsessile to shortly pedicellate, with furcate or truncate pedicel, apically rounded, with an distinct ocular chamber. Ascospores 40–55 μm × 5–8 μm (x̄ =48 × 7 μm, n=20), 2–3-seriate, 1–2-septate when immature, 3-septate when mature, fusiform, slightly curved, hyaline, not constricted at the septa, smooth-wall with small guttules, covered by a thin, distinct gelatinous sheath. Asexual morph: Undetermined.

Culture characteristics: Ascospores germinating on PDA within 24 h. Colonies reach 32 mm diam. in 15 days under dark and at 28 °C conditions. Colonies circular, hairy, entire edge, the color of the colonies center is light brown, the outward color gradually becomes dark, and the color of the margin is dark brown from above, dark brown from below, and producing pigmentation on agar medium.

Material examined: China, Yunnan Province, Dali, Cangshan mountain , (25°41′22″ N, 108°8′2″ E, 2381.26 m), on dead culm of bamboo, 11 July 2021, D.Q. Dai, DDQ02030 ( GMB1291 , holotype), living culture, ex-type living culture, GMBCC1128 ; Ibid. ( ZHKU 22-0158 , isotype), ex-isotype living culture, ZHKUCC 22-0290 .

Notes: The nucleotide BLAST search of ITS sequence indicated that Parabambusicola yunnanensis (GMBCC1128 and ZHKUCC 22-0290) is similar to P. bambusina strain H4321 (87.42% similarity under 85% query cover), and strain KT2637 (87.23% similarity under 85% query cover). Nucleotide BLAST results of LSU sequence showed that P. yunnanensis (GMBCC1128 and ZHKUCC 22-0290) is similar to P. aquatica strain MFLUCC 18- 1140 (97.88% similarity under 97% query cover), and P. bambusina strain H4321 (87.43% similarity under 98% query cover).

Based on a nucleotide pairwise comparison of ITS and LSU sequences showed that P. yunnanensis differs from P. aquatica (MLFUCC 18-1140, type strain) in 118/510 bp of ITS (23.1%), and 35/859 bp of LSU (3.03%). Parabambusicola yunnanensis differs from P. bambusina (H 4321, KT 2637, KH 139) in 124/536 bp of ITS (23.1%), and 26/858 bp of LSU (1.42%). Parabambusicola yunnanensis differs from P. hongheensis in 130/536 bp of ITS (24.2%), and 37/858 bp of LSU (4.3%). Our new species also differs from P. thysanolaenae (KUMCC 18-0147, type strain) in 136/536 bp of ITS (25.3%), and 33/858 bp of LSU (3.8%). Morphology of the new collection shares similar general characteristics with Parabambusicola in having immersed, raised ascomata, cylindrical, short, furcate-basedpedicellate asci with an ocular chamber and hyaline, fusiform, septate ascospores ( Tanaka et al. 2015, Phookamsak et al. 2019, Dong et al. 2020, Xie et al. 2022). However, P. yunnanensis can be distinguished from P. aquatica and P. thysanolaenae in having 3-septate ascospores, while P. aquatica has 5-septate ascospores, P. thysanolaenae has 5–(6–7)-septate ascospores ( Phookamsak et al. 2019, Dong et al. 2020). In addition, P. yunnanensis has longer asci (130–180 × 20–30 μm vs. 86–150 × 22–30 μm) than P. bambusina ( Tanaka & Harada 2003, Tanaka et al. 2015). Parabambusicola hongheensis has wider peridium (20–75 µm vs. 8–15 µm) and wider ascospores (50–55 × 12–15 μm vs. 40–55 × 5–8 μm) than P. ynnanensis ( Xie et al. 2022) . Detailed morphological characteristics are mentioned in Table 2 . Phylogenetic analyses also proved that the new strains formed a well-separated branch with other species of Parabambusicola (100% ML and 1.00 PP, Figure 1 ). Based on morphological and phylogenetic studies, our new collection of Parabambusicola is introduced as a new species occurring on bamboo from China.

Figures

FIGURE 1. The RAxML tree based on the combined ITS, LSU, SSU, and tef1-α sequence data. Bootstrap support values for ML equal to or greater than 60%, and Bayesian posterior probabilities (BYPP) equal to or higher than 0.90 are indicated above the nodes as ML/PP. The ex-type strains are indicated by superscript “T”, while the newly generated sequences are shown in red.

FIGURE 2. Parabambusicola yunnanensis (GMB1291, holotype). a. Bamboo specimen. b. Black ascomata on the host surface. c. Vertical sections of ascomata. d. Ostiole. e, f. Peridium. g. Pseudoparaphyses. h−k. Asci. l−o. Ascospores. p. An ascospore in India ink. q. A germinating ascospore. r. Cultures on PDA from above and below. Scale bars: b = 500 μm; c = 300 μm; d, h−k = 50 μm; e−g = 15 μm; l−q = 20 μm.