Dothiorella hortiarborum Y. Y. Wu & C. M. Tian, 2024

Wu, Yingying, Peng, Cheng, Yuan, Rong, Zhang, Mingwei, Hu, Yang & Tian, Chengming, 2024, New species and records of Botryosphaeriales (Dothideomycetes) associated with tree dieback in Beijing, China, MycoKeys 106, pp. 225-250 : 225-250

Dothiorella hortiarborum Y. Y. Wu & C. M. Tian sp. nov.

Fig. 5

Etymology.

“ Hort ” means “ garden, ” and “ arbor ” means “ tree ” in Latin. Collected from Fraxinus chinensis and Lagerstroemia indica , both of which are landscaping and greening trees.

Holotype.

China, Beijing City, Tongzhou District, Central Green Forest Park , 39 ° 52 ' 16 " N, 116 ° 42 ' 04 " E, on the dead branches of Fraxinus chinensis , 19 April 2023, C. M. Tian, C. Peng, R. Yuan, M. W. Zhang & Y. Y. Wu (holotype BJFC - S 1951 , ex-type cultures CFCC 70756 ).

Description.

Sexual morph: Not observed. Asexual morph: Conidiomata pycnidial, scattered to aggregated, immersed to semi-immersed in bark, globose to subglobose, dark gray to black, unilocular, 260–450 μm diam. Disc black, ovoid, 310–330 μm diam. Ostioles single, light gray, circular, central, papillate, 30–45 μm diam. Locules single, black, oval, 100–380 μm, Conidiophores reduced to conidiogenous cells. Conidiogenous cells: hyaline, smooth, thin-walled, holoblastic, cylindrical to subcylindrical, 4.5–11.0 × 2.0–4.0 μm (av. ± S. D. = 6.8 ± 1.3 × 2.9 ± 0.5 µm). Conidia initially hyaline, then producing light yellow pigmentation, uneven surface, thick-walled, dark brown when matrues, 1 - septate, constricted at the septum, smooth, ovoid with a broadly rounded apex, truncate base. 10.0–19.0 × 6.0–11.0 μm (av. ± S. D. = 14.9 ± 2.6 × 8.1 ± 1.0 µm).

Culture characters.

Colonies on PDA with aerial mycelium gray-green, thick and dense, fluffly, margin with undulate and irregular, reverse with inky blue pigment accumulation, reaching 60 mm diam in 7 days at 25 ° C.

Other material examined.

China, Beijing City, Tongzhou District, Central Green Forest Park , 39 ° 52 ' 16 " N, 116 ° 42 ' 04 " E, on the dead branches of Fraxinus chinensis , 19 April 2023, C. M. Tian, C. Peng, R. Yuan, M. W. Zhang & Y. Y. Wu, BJFC - S 2366 , living culture CFCC 70757 ; China, Beijing City, Tongzhou District, Central Green Forest Park , 39 ° 52 ' 16 " N, 116 ° 42 ' 04 " E, on the dead branches of Lagerstroemia indica , 19 April 2023, C. M. Tian, C. Peng, R. Yuan, M. W. Zhang & Y. Y. Wu, BJFC - S 1952 , living culture CFCC 70758 ; ibid. BJFC - S 2367 , living culture CFCC 70759 .

Notes.

Dothiorella hortiarborum formed an independent clade with 87 % MP, 97 % ML, and 0.99 BYPP values and is distinct from Do. acericola and Do. plurivora in the multi-locus analyses (Fig. 3 ). Morphologically, Do. hortiarborum can be distinguished from Do. acericola by shorter conidia ( Phookamsak et al. 2019) and Do. plurivora by smaller conidia (10.0–19.0 × 6.0–11.0 μm vs. 22.3–22.7 × 10.8–11.2 μm) ( Abdollahzadeh et al. 2014). Additionally, Do. hortiarborum differs from Do. acericola in tef 1 - α (five bp difference from 170 characters, with 97.1 % similarity, including no gaps) sequences, and Do. plurivora in tef 1 - α (one bp difference from 254 characters, with 99.6 % similarity, including one gap), tub 2 (three bp difference from 370 characters, with 99.2 % similarity, including one gap) sequences.

Figures

Figure 3. Phylogram generated from RAxML analysis based on ITS, tef 1 - α, and tub 2 sequence data of Dothiorella isolates. The tree was rooted in Neofusicoccum luteum (CBS 562.92) and Neofusicoccum parvum (CMW 9081). The MP, ML (≥ 50 %), and BI (≥ 0.9) bootstrap supports are given near the nodes, respectively. Isolates from this study are marked in blue, and ex-type strains are marked in bold.

Figure 5. Dothiorella hortiarborum (BJFC - S 1951) A, B habit of conidiomata on branch C transverse section of conidioma D longitudinal section through conidioma E, F conidiogenous cells and conidia G top (left) and bottom (right) sides of colonies on potato dextrose agar (PDA) H, I conidia. Scale bars: 1000 μm (A); 200 μm (B – D); 10 μm (E – F, H – I).