Phylogenetic analysis
The phylogenetic tree based on the five-locus analysis (Fig. 1) shows the relationship between the new species and other related taxa. The dataset including alignment gaps comprised 4415 characters: 646 for ITS, 843 for LSU, 999 for SSU, 873 for TEF1 and 1054 for RPB2. Branchs support of MLBS ≥70% and PP value≥0.90 are indicated above branches. The tree is rooted to Dothidea insculpta CBS 189.58. The new species Aquapteridospora jiangxiensis JAUCC3008 together with other Aquapteridospora species formed a well-supported clade (BPP = 1, MLBS = 100%).
Taxonomy
Aquapteridospora jiangxiensis J.E. Huang, H.Y. Song & D.M. Hu, sp. nov.
Mycobank No: 841242
Etymology: In reference to the host location, Jiangxi province, where the holotype was collected.
Holotype: HFJAU 3176
Saprobic on decaying submerged wood. Sexual morph Undetermined. Asexual morph Hyphomycetous. Colonies effuse consisting of conidiophores scattered over the substrate surface, brown to dark brown. Mycelium septate, hyaline, partly immersed and partly superficial on the natural substrate. Conidiophores 78–305 × 4–7 μm (mean = 144.3 × 4.7 μm, n = 20),macronematous, mononematous, cylindrical, erect, usually straight or slightly flexuous and sometimes flexuous, smooth, 3–15-septate, unbranched, dark brown in the middle and below, pale brown above, thick-walled, with abundant small guttulae, occasionally slight swollen at the base. Conidiogenous cells polyblastic, 20–68 × 4–6 μm (mean = 41.2 × 4.8 μm, n = 20), integrated, terminal, becoming intercalary, pale brown to brown, smooth, subclavate to subcylindrical, with several sympodial proliferations, bearing some conspicuous, rounded, brown to mid-brown denticles. Conidia 20–25 × 6–7.5 μm (mean = 22.5 × 6.5 μm, n = 25) μm, acrogenous or lateral, fusiform to subclavate, rounded at the apex, base truncate, 0.9–1.5 μm wide, straight to slightly curved, 3-septate, slightly constricted at septa and septa dark brown to black, with mid to dark brown central cells and pale to mid brown end cells, with abundant small guttulae, smooth-walled, sometimes with a sheath.
Culture characteristics: Conidia germinating on PDA within 24 h. Colonies growing on PDA, circular, reaching 40–60 mm diam. after 2–3 weeks at 28 ℃; from above, flat, center grey-white with some dark brown spots and edge dark brown, mycelium superficial to immersed in media; from below, center grey-brown, near the edge black, with smooth margin.
Material examined: CHINA, Jiangxi Province, Shangrao, Dexing, Xiangtun Street, on submerged wood in a stream, 12 August 2018, J.E. Huang (Holotype, HFJAU 3176); ex-type living culture (JAUCC 3008).
Notes: The phylogenetic analysis based on combined data of ITS, LSU, SSU, TEF1 and RPB2 sequences showed that Aquapteridospora jiangxiensis clusters within Aquapteridospora clade with high bootstrap support (Fig. 1). Morphologically, A. jiangxiensis is characterized by its unbranched and guttulate conidiophores with multi-septa and swollen at the base, polyblastic conidiogenous cells with sympodial proliferations and denticles, guttulate conidia with a sheath, which fits well with the concepts of the genus Aquapteridospora (Yang et al. 2015). Aquapteridospora jiangxiensis shows obvious distrance to the other species of Aquapteridospora in the phylogenetic tree (Fig. 1). Morphologically, A. jiangxiensis differs from the other four species of Aquapteridospora by its fusiform to subclavate conidia with rounded apex and truncate base.
Aquapteridospora bambusinum (D.Q. Dai & K.D. Hyde) J.E. Huang, H.Y. Song & D.M. Hu, comb. nov.
Mycobank No: 841243
≡ Pleurophragmium bambusinum D.Q. Dai & K.D. Hyde, in Dai, Phookamsak, Wijayawardene, Li, Bhat, Xu, Taylor, Hyde & Chukeatirote, Fungal Diversity 82: 90 (2017).
Notes: Pleurophragmium bambusicola is characterized by polyblastic, sympodial, denticulate conidiogenous cells and 3-septate, brown, thick-walled conida (Dai et al. 2017), which fit the generic concepts of Aquapteridospora (Yang et al. 2015). On the phylogenetic tree (Fig 1), the type strain (MFLUCC 12-0805) of Pleurophragmium bambusicola clusters within Aquapteridospora clade with high bootstrap support (BPP = 1, MLBS = 100%). Therefore, we transfer Pleurophragmium bambusicola to the genus Aquapteridospora.