Thelonectria guangdongensis Z.Q. Zeng & W.Y. Zhuang

Zeng, Zhao-Qing & Zhuang, Wen-Ying, 2019, The genera Rugonectria and Thelonectria (Hypocreales, Nectriaceae) in China, MycoKeys 55, pp. 101-120 : 101

Thelonectria guangdongensis Z.Q. Zeng & W.Y. Zhuang sp. nov. Figure 3

Holotype.

CHINA. Guangdong, Shixing, Chebaling, (24°43'17.38"N, 114°16'39.50"E), alt. 600 m, on branches, 2 November 2015, Z.Q. Zeng, X.C. Wang, K. Chen, Y.B. Zhang 10627 (HMAS 254522); ex-type culture: HMAS 247233.

Sequences.

ACT (MF669045), ITS (MF669051), LSU (MF669053) and RPB1 (MF669057).

Etymology.

The specific epithet refers to the type locality of the fungus.

Description.

Mycelium not visible around ascomata or on natural substrata. Ascomata perithecial, solitary to gregarious, up to 10 in a group, with a well–developed stroma, superficial, subglobose to globose, bright red with a prominently darkened papilla, turning dark red in KOH, becoming slightly yellow in LA, 235-382 × 245-412 μm (n = 8). Perithecial surface slightly roughened. Perithecial wall of two layers, 20-50 µm thick, outer layer 13-37 µm thick, of textura intricata; inner layer 7.5-13 µm thick, of textura prismatica. Asci not observed. Ascospores ellipsoid, 1-septate, smooth, 10-13 × 3-5 µm (11.6 ± 1.3 × 4.2 ± 0.7 μm). Colony on PDA 28 mm diameter after 7 d under daylight at 25 °C, surface velvety, with white aerial mycelium, producing purple pigment in medium. Colony on SNA 35 mm diameter after 7 d under daylight at 25 °C, surface with sparse whitish aerial mycelium. Phialides cylindrical or slightly swollen, 20-58 × 2-4 μm. Macroconidia cylindrical, slightly curved with rounded ends, 2-5-septate, 48-70 × 4.8-5.3 μm (58.9 ± 7.14 × 5.0 ± 0.2 μm). Microconidia and chlamydospores not observed in culture.

Habitat.

On branches.

Distribution.

Asia (China).

Notes.

Amongst species of Thelonectria , T. guangdongensis resembles T. phoenicea in having subglobose to globose perithecia with slightly roughened surface, purple colony, lack of microconidia and number of septa in macroconidia ( Salgado-Salazar et al. 2015). However, T. phoenicea has much larger perithecia 300-600 × 200-350 μm, wider ascospores that are 4-5.5 μm wide, and wider phialides 3-6.5 μm wide ( Salgado-Salazar et al. 2015). Moreover, there are 13 bp, 44 bp, 8 bp and 54 bp divergences in the ACT, ITS, LSU and RPB1 regions, respectively, between the type of T. guangdongensis (HMAS 254522) and that of T. phoenicea (G.J.S. 85-179).

Phylogenetically T. guangdongensis is closely related to T. beijingensis with strong statistical support (MLBP/MPBP/BIPP = 100%/97%/100%) ( Figure 1 ). However, T. beijingensis differs in having larger ascospores that are 13-17 × 4-7 μm, while those of T. guangdongensis are 10-13 × 3-5 µm and form microconidia in culture in addition to macroconidia ( Zeng and Zhuang 2013). There are 20 bp, 30 bp, 5 bp and 50 bp divergences in the ACT, ITS, LSU and RPB1 regions between the ex-type culture of T. guangdongensis and that of T. beijingensis (HMAS 188498). Both morphology and molecular data support the establishment of the new species.

Figures

Figure 1. A Maximum Parsimony tree inferred from the combined ACT, ITS, LSU and RPB 1 sequences. Cosmospora coccinea and Nectria cinnabarina were used as outgroup taxa. MLBP (left) and MPBP (middle) above 50 %, BIPP (right) above 90 % are indicated at nodes.

Figure 3. Thelonectria guangdongensis a-d ascomata on natural substratum e colony on PDA f colony on SNA g median section through perithecium h-m ascospores n, q, r conidiogenous cells and macroconidia o, p, s-u macroconidia. Scale bars: 0.5 mm (a-d); 50 μm (g); 10 μm (h-u).