Arthrographis guizhouensis H. Y. Wang & Y. F. Han sp. nov.

Fig. 6

Etymology.

The epithet “guizhouensis” refers to the locality, Guizhou Province, where the type was isolated and collected.

Type.

China • Guizhou Province, Tongren City, Tea Garden (28°02'47"N, 108°33'41"E), rhizosphere soil of tea plant, April 2025, Haiyan Wang, ex-type culture GZUIFR 25.211, dried holotype GZAC 25.211.

Description.

Rhizosphere fungi associated with the tea plant. The fungus sporulated on PDA medium after 14 days of incubation at 25 ° C. Vegetative hyphae septate, hyaline, thick-walled, simple to branched, 1.0–4.0 μm wide. Conidiophores reduced to conidiogenous hyphae. Conidiogenous hyphae hyaline, smooth-walled, mostly erect, clavate, aseptate, simple or unbranched, up to 40.0 μm long, forming arthroconidia from the top to the base. Arthrospores in single or branched chains, or solitary, unicellular, arising from conidiogenous hyphae or vegetative hyphae, abundant, hyaline, smooth-walled, ovoid and elliptical, lateral, terminal, 2.5–9.0 × 2.5–5.0 μm (av. 4.71 × 3.30 μm, n = 30). Chlamydospores globose or subglobose, smooth, abundant, unicellular, thick-walled, 5.0–9.0 μm.

Sexual morph.

Not observed.

Culture characteristics.

Colony on PDA, after 14 days of incubation at 25 ° C, reaching up 20–25 mm diam., thick, short villiform, radial mycelium, fleshcolor at the center, creamy white at the edge, exudates and diffusible pigments absent, reverse creamy white, regular in the margin; Colony on MEA, reaching up 20–25 mm diam., villiform, moist, creamy white at the center, pale brown at the edge, exudates and diffusible pigments absent, reverse pale brown, regular in the margin; Colony on OA, reaching up 20–25 mm diam., thin, fluffy, flocculence, gray white, damp marks, reverse gray white, irregular in the margin.

Additional specimens examined.

China • Guizhou Province, Tongren City, Tea Garden (28°02'47"N, 108°33'41"E), rhizosphere soil of tea plant, April 2025, living cultures GZUIFR 25.212; ibids., GZUIFR 25.213, GZUIFR 25.214.

Notes.

BLASTn analysis with the ITS sequences of Arthrographis guizhouensis showed similarity to A. kalrae with a percent similarity of 96.23 % without gaps. The analysis with LSU sequences of A. guizhouensis showed similarity to A. curvata with a percent similarity of 99.03 % without gaps, and the analysis with ACT sequences of A. guizhouensis showed similarity to A. kalrae with a percent similarity of 96.10 % with 4 gaps. Phylogenetically, the four strains (GZUIFR 25.211, GZUIFR 25.212, GZUIFR 25.213, and GZUIFR 25.214) of the new species formed a monophyletic subclade with a high support value (1.00 BYPP and 99 % MLBS; Fig. 3) and had a close relationship with A. grakistii Giraldo López & Hern. - Restr. and A. longispora A. Giraldo, Deanna A. Sutton, Cano & Guarro. However, they were obviously different in morphological characteristics. Arthrographis guizhouensis does not produce conidiophores or has conidiophores reduced to conidiogenous hyphae, has solitary or branched chains, ovoid and elliptical arthrospores from conidiogenous hyphae or vegetative hyphae, and has no synasexual morph, which can be distinguished from A. longispora and A. grakistii. Arthrographis longispora has cylindrical arthroconidia with truncate or rounded ends (Giraldo et al. 2014). Arthrographis grakistii has semi-macronematous or micronematous conidiophores and cylindrical or cuboid arthroconidia (Hernández-Restrepo et al. 2020). Therefore, Arthrographis guizhouensis is introduced as a new species.