Periconia guangxiense X. G. Tian & D. F. Bao, 2025

Tian, Xing-Guo, Han, Jia-Jun, Hongsanan, Sinang, Lu, Yong-Zhong, Karunarathna, Samantha C., Bao, Dan-Feng & Tibpromma, Saowaluck, 2025, Two new Periconia species (Pleosporales, Ascomycota) in China, MycoKeys 125, pp. 307-324 : 307-324

Periconia guangxiense X. G. Tian & D. F. Bao sp. nov.

Fig. 2

Holotype.

GZAAS 25-0735. The holotype GZAAS 25-0735 is the representative specimen of Periconia guangxiense , collected from decaying submerged wood in a freshwater stream in Longlin City , Guangxi Province, China, on 24 November 2024, by Dan-Feng Bao (collection code: NPJ 8-30/B 199). This holotype specimen is deposited in the herbarium of Guizhou Academy of Agricultural Sciences ( GZAAS) in Guiyang, China, while its corresponding ex-type living culture ( GZCC 25-0705 ) is stored in the Guizhou Culture Collection ( GZCC).

Etymology.

Named after the type location, “ Guangxi ”.

Description.

Saprobic on decaying submerged wood in freshwater habitats. Sexual morph Undetermined. Asexual morph Hyphomycetous. Colonies effuse on natural substrate, scattered, hairy, dark brown to dark. Mycelium composed of cottony hyphae, forming dark clusters with conidia. Conidiophores micronematous to semi-macronematous, mononematous, branched, caespitose, straight or flexuous, hyaline when young, turning brown to dark brown, cylindrical, septate, smooth-walled. Conidiogenous cells 19–28 × 2.5–4.5 μm (x ̄ = 23 × 3.5 μm, n = 6), mono- to polyblastic, determinate, discrete on stipe, intercalary, smooth to minutely verruculose, ellipsoid to cylindrical, brown. Conidia 6–7.5 μm diam. (x ̄ = 6.8 μm, n = 60), subglobose to globose, aseptate, reddish-brown to dark brown, arising at one or more points on the curved surface of the conidiogenous cell, in branched chains, bud scars or disjunctors present at the site of attachment, verruculose.

Culture characteristics.

Conidia germinated on PDA within 24 hr, reaching 20 mm diam. in 2 weeks at 25 ° C. Colonies on PDA with white mycelia on the surface, cottony, circular, and flattened; reverse reddish brown with a pink margin, not sporulate on PDA after two weeks.

Material examined.

China • Guangxi Province, Longlin City , on decaying submerged wood, 24 Nov. 2024, D. F. Bao, NPJ 8-30 (B 199) ( GZAAS 25-0735 , holotype), ex-type, GZCC 25-0705 ; ibid. NPJ 8-12 ( GZAAS 25-0733 , isotype), ex-isotype, GZCC 25-0704 .

GenBank numbers.

GZCC 25-0705 : ITS = PX 118886, LSU = PX 118882, SSU = PX 118890, tef 1 - α = PX 522310; GZCC 25-0704 : ITS = PX 118887, LSU = PX 118883, SSU = PX 118891, tef 1 - α = PX 522311.

Notes.

In the phylogenetic analyses of the combined ITS, LSU, SSU, and tef- 1 α sequence data, our newly obtained strains of Periconia guangxiense ( GZAAS 25-0735 ) formed a distinct lineage and clustered sister to P. variicolor strains (SACCR 64, isolate 5, F 5, isolate 39 JAN, BHE 4) with 92 % ML and 1.00 PP statistical supports (Fig. 1 ). Morphologically, Periconia guangxiense ( GZAAS 25-0735 , holotype) can be easily distinguished from P. variicolor (CBS 120374) by micronematous, branched conidiophores, while P. variicolor has macronematous and unbranched conidiophores. Periconia guangxiense also has a smaller size range of conidia (6–7.5 µm vs. 7.5–9.5 μm) than the holotype of P. variicolor (CBS 120374) ( Cantrell et al. 2007). In addition, pairwise nucleotide comparisons showed that ITS of Periconia guangxiense ( GZCC 25-0705 ) differed 40 / 508 bp (7.87 %, with gaps) from that of P. variicolor (SACCR- 64), which strongly supports our strains as a new species. The PHI test revealed no significant recombination event between our strains ( GZAAS 25-0735 and GZAAS 25-0733 ) and the closely related taxa. The significant recombination between our two strains indicates that they are conspecific (Φw = 0.98) (Fig. 4 ). Therefore, Periconia guangxiense is introduced as a distinct new species of Periconia .

Figures

Figure 1. Phylogram generated from maximum likelihood (ML) analysis based on a concatenated alignment of ITS, LSU, SSU, and tef 1 - α sequences in Periconiaceae. Related sequences were obtained from Bao et al. (2025). The tree was rooted with Morosphaeria ramunculicola (KH 220) and M. velatispora (KH 221). Bootstrap support values for ML equal to or greater than 60 % and clade credibility values greater than 0.90 from Bayesian inference analysis are labelled at each node. The new isolates are indicated in red, while “ T ” indicates holotype or ex-type strains.

Figure 2. Periconia guangxiense (GZAAS 25-0735, holotype). a, b. Colonies on submerged decaying wood; c – f. Conidial masses; g – i. Conidiogenous cells with conidia; j – m. Conidia; n – o. Culture on PDA from obverse and reverse view. Scale bars: 30 μm (c – d); 20 μm (e – f); 10 μm (g – m).

Figure 4. Results of the PHI test of the new species and closely related species using both LogDet transformation and splits’ decomposition. The new strains are in red font, and “ T ” indicates holotype or ex-type strains.