Bambusicola pseudodimorphae Y. Feng, Z. Y. Liu & Jian K. Liu, 2025

Feng, Yao, Chen, Ya-Ya, Lin, Chuan-Gen, Liu, Zuo-Yi, Chen, Xiao-Fang, Pei, Guo-Shun & Liu, Jian-Kui, 2025, Morpho-phylogenetic evidence reveals novel Bambusicolous fungi from Guizhou Province, China, MycoKeys 118, pp. 81-103 : 81-103

Bambusicola pseudodimorphae Y. Feng, Z. Y. Liu & Jian K. Liu sp. nov.

Figs 4 , 5

Holotype.

HKAS 112597.

Etymology.

Species epithet refers to the similar conidia to Bambusicola dimorpha which have two types in culture.

Description.

Saprobic on bamboo culms. Sexual morph: Undetermined. Asexual morph: Conidiomata initially embedded in the epidermis of bamboo culms and later breaking through the epidermis, solitary to gregarious, subglobose with a flattened base, brown to dark brown. 78–161 μm high, 180–270 μm diam. Conidiomatal wall comprising 3–5 layers of cells of textura angularis, with dark brown outer layers and hyaline inner layers, less distinguished from the host tissue. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 9–32 × 1–2 μm (x ̄ = 23 × 2 μm, n = 15), holoblastic, monoblastic, cylindrical, smooth, hyaline. Conidia 24–27 × 3–4 μm (x ̄ = 26 × 4 μm, n = 30), initially hyaline to pale brown, aseptate, becoming yellowish brown, 2–3 - septate when maturity, cylindrical, obtuse at both ends, smooth-walled, straight, guttulate.

Culture characteristics.

Colonies on PDA slow growing, 16 mm diam. after 10 d at 25 ° C in dark, circular, with an entire margin, white, fluffy, with dense mycelium on the surface. Reverse white with a yellowish center. After being cultivated on PDA for two months, Bambusicola pseudodimorphae generated two types of conidia, macro- and microconidia. Macroconidia 20–26 (– 29) × 3–5 μm (x ̄ = 24 × 4 μm, n = 30), cylindrical, with obtuse and rounded ends, 3 - septate, pale brown to brown, smooth-walled. Microconidia 3–4 × 1–3 μm (x ̄ = 4 × 2 μm, n = 30), ellipsoidal, pale brown, aseptate.

Material examined.

China • Guizhou Province, Xingyi City . On dead bamboo stems, 5 September 2019, Yao Feng, XY 19-3 ( HKAS 112597 , holotype; GZAAS 21-0501 , isotype), ex-type living cultures CGMCC 3.20353 = GZCC 21-0801 ; ibid., 6 September 2019, Yao Feng, XY 19 b ( GZAAS 21-0388 , paratype), living culture GZCC 21-0896 .

Notes.

Phylogenetic analyses revealed that the two strains of Bambusicola pseudodimorphae clustered with B. bambusae , B. dimorpha , B. ficuum , and B. pustulata , forming a distinct lineage within Bambusicola (Fig. 1 ). Morphologically, B. pseudodimorphae closely resembles is similar to B. dimorpha in having two types of conidia. However, B. pseudodimorphae differs by having smaller conidiomata (78–161 × 180–270 μm vs. 200–250 × 210–340 μm) and longer conidia (24–27 μm long, 3 - septate vs. 13–21 μm long, 1 - septate) ( Thambugala et al. 2017). Since our collection is an asexual morph, and the other three species ( B. bambusae , B. ficuum , and B. pustulata ) are known as sexual morphs, direct comparisons between them are not feasible. Molecular analyses further support the distinction of B. pseudodimorphae as a novel species. The tef 1 - α and rpb 2 sequences of B. pseudodimorphae differ from those of B. bambusae by 3 % (32 / 924 bp) and 3 % (35 / 1001 bp) nucleotides, respectively. Additionally, the rpb 2 sequence of B. pseudodimorphae showed 96 % (945 / 984 bp, one gap) and 97 % (853 / 880 bp, no gap) sequence similarity with B. pustulata and B. dimorpha , respectively. Based on the morphology and molecular evidence, B. pseudodimorphae is identified as a new species following the species delineation guidelines of Jeewon and Hyde (2016).

Figures

Figure 1. Phylogram generated from maximum likelihood analysis based on a combined dataset of SSU, ITS, LSU, rpb 2 and tef 1 - α sequences. Bootstrap support values for ML (≥ 75 %) and bayesian posterior probabilities (≥ 0.95) are given at the nodes (ML BS / PP). Branches with 100 % ML BS and 1.00 PP are thickened. New strains are shown in red. The tree is rooted with Sulcatispora berchemiae KT 1607 and Sulcatispora acerina KT 2982, and ex-type strains are in bold.

Figure 4. Bambusicola pseudodimorphae (HKAS 112597, holotype) A, B conidiomata on the host C vertical section of a conidioma D germinated conidium E, F cultures on PDA E from above F from below G-K conidiogenous cells and developing conidia L-P conidia. Scale bars: 100 µm (C); 20 µm (D); 5 µm (G-I); 10 µm (J-P).

Figure 5. Reproduced Bambusicola pseudodimorphae (CGMCC 3.20353, ex-type) A, B colony on PDA C-F conidiogenous cells with conidia G-J macroconidia K microconidia. Scale bars: 10 µm (C-K).