Amphibambusa hongheensis H.B. Jiang & Phookamsak, 2021

Jiang, Hong-Bo, Zhang, Shi-Jie, Phookamsak, Rungtiwa, Promputtha, Itthayakorn, Kakumyan, Pattana & Xu, Jian-Chu, 2021, Amphibambusa hongheensis sp. nov., a novel bambusicolous ascomycete from Yunnan, China, Phytotaxa 505 (2), pp. 201-212 : 206-207

Amphibambusa hongheensis H.B. Jiang & Phookamsak , sp. nov. FIGURE 2

Index Fungorum number: IF558309; Facesoffungi number: FoF 09738

Etymology: The specific epithet “ hongheensis ” refers to the location, Honghe County, Yunnan, where the new species was collected. Holotype: KUN-HKAS 112723

Saprobic on dead bamboo culms, visible as black circular, or ellipsoid spots on host surface. Sexual morph: Ascomata 350–600 μm diam., 300–500 μm high, gregarious, scattered, deeply immersed in host tissues, globose to subglobose, dark brown to black, softened, uni-loculate, glabrous, with a black clypeus penetrating host surface. Ostioles central, carbonaceous, easily cracked, minute papilla, protruding through host surface, opening surrounded by white margin. Peridium 20–35 μm thick, composed of 5–7 layers of flattened, dark brown to black pseudoparenchymatous cells, textura angularis, inner layers comprising 1–2 layers of flattened, hyaline cells. Paraphyses 3–10 μm broad, hyaline, filiform to filamentous, straight to curved, unbranched, septate, slightly constricted at the septa, broader at the base, tapering towards the apex, with large to small guttules. Asci (118–)125–160 × (14–)15.5–17.5(–18) μm (x̅ = 143 × 16.6 μm, n = 20), 8-spored, unitunicate, cylindrical to elongate fusiform, wider in the middle, tapering towards both ends, subsessile to a short furcate pedicel, apically rounded with a small, J+, subapical ring. Ascospores (25.5–)27–31.5(–33) × 5.5–6.5(–7) μm (x̅ = 29 × 5.9 μm, n = 20), overlapping 1–2-seriate, hyaline to pale brown, fusiform, with round end cells, 1-septate, slightly constricted at the septum, ornamented wall with a longitudinally striation, surrounded by a 4–15.8(–25) μm thick, distinct, mucilaginous sheath. Asexual morph: Undetermined.

Culture characteristics: Ascospores germinated on PDA within 24 hours and a germ tube initially produced from the upper cell. Colonies on PDA reaching 10 mm in 4 weeks at room temperature (10–25̊ C), effuse, hairy, circular, irregular at the margin, white from the above and yellowish from the below. Mycelium immersed in PDA, branched, septate, smooth-walled, hyaline hyphae.

Material examined: China, Yunnan Province, Honghe Hani and Yi Autonomous Prefecture , Honghe County (23°16’32.26″N, 102°25’30.37″E, altitude 1544 m), on dead culms of bamboo in terrestrial environment, 28 October 2020, H.B. Jiang, HONGHE014 (KUN-HKAS 112723, holotype; ibid., HMAS 249942 , isotype) , ex-type living culture, KUMCC 20-0334 .

Notes: Amphibambusa hongheensis is typical of Amphibambusa and resembles A. bambusicola in forming ascomata immersed in a black clypeus, with ostiolar opening surrounded by white margin, cylindrical asci with a J+, subapical ring, and fusiform, longitudinally striated ascospores, surrounded by a distinct mucilaginous sheath. However, A. hongheensis has smaller asci [(118–)125–160 × (14–)15.5–17.5(–18) μm vs. 150–200 × 17.5–20 μm], longer ascospores [(25.5–)27–31.5(–33) × 5.5–6.5(–7) μm vs. 25–27 × 5.5–6 μm] than those of A. bambusicola . Moreover, the ascospores of A. bambusicola are fusiform to broad-fusiform, with pointed end cells, and deeply constricted at the septum ( Liu et al. 2015), which are absent in A. hongheensis . Phylogenetic analyses of a concatenated ITS-LSU sequence dataset depict A. hongheensis as a sister taxon of A. bambusicola . Furthermore, a nucleotide pairwise comparison showed that A. hongheensis differs from A. bambusicola in 35/428 bp of ITS (8.18%, without gaps) and 16/858 bp of LSU (1.86%, without gaps).

Figures

FIGURE 2. Amphibambusa hongheensis (KUN-HKAS 112723, holotype). a Appearance of ascomata on the host. b Vertical section of the ascoma. c Peridium. d–f Asci. g Paraphyses. h, i Cultures. j J+, subapical ring (stained in Melzer’s reagent). k–n Ascospores (notes: k ascospore with longitudinal striation, n ascospore stained in Indian ink showing mucilaginous sheath). Scale bars: b = 100 μm, d–g = 30 μm, c = 20 μm, j–n = 15 μm.