Dendrostoma rizhaoense Ning Jiang, 2024

Jiang, Ning, Qi, Xiaojie, Qi, Baoxin, Cai, Fang, Xue, Han & Li, Yong, 2024, Two new species of Dendrostoma (Erythrogloeaceae, Diaporthales) associated with Castanea mollissima canker disease in China, MycoKeys 108, pp. 337-349 : 337-349

Dendrostoma rizhaoense Ning Jiang sp. nov.

Fig. 2

Etymology.

Named after the collection site of the type specimen, Rizhao City.

Holotype.

CAF 800092 .

Description.

Sexual morph: Undetermined. Asexual morph: Conidiomata formed on PDA, pycnidial, ostiolated, conical to pulvinate, occurring separately, brown, 150–350 μm high, 200–450 μm diam.; wall of several layers of faint yellow textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells lining the inner walls of the cavity, hyaline, smooth, subcylindrical to ampulliform, 8–27.5 × 3–5.5 μm. Conidia hyaline, aseptate, smooth, multiguttulate, thin-walled, ellipsoid to fusoid, straight, (5.6 –) 6.4–8.8 (– 10.7) × (2.4 –) 2.7–3.8 (– 4.5) μm, l / w = (1.5 –) 1.8–3.1 (– 3.8) (n = 50).

Culture characteristics.

Colonies on PDA flat, initially white, becoming dark orange after 2 weeks, texture uniform, producing conidiomata after 4 weeks.

Materials examined.

China • Shandong Province, Rizhao City, Lanshan District, Huangdun Town , on cankered barks of Castanea mollissima , 16 October 2022, Jiang Ning ( CAF 800092 , holotype); ex-type cultures CFCC 57559 and CFCC 57560 .

Notes.

Two isolates of Dendrostoma rizhaoense from Castanea mollissima formed a distinct clade in the phylogram of this genus based on the combined sequence of ITS, tef 1 and rpb 2 (Fig. 1 ). With two new species proposed in the present study, nine species of Dendrostoma were recorded from the host Castanea mollissima , viz. D. aurorae , D. castaneae , D. castaneicola , D. chinense , D. parasiticum , D. rizhaoense , D. shaanxiense , D. shandongense and D. tianii ( Jiang et al. 2019) . Morphologically, D. rizhaoense (6.4–8.8 μm) has shorter conidia than D. castaneae (10.4–12.3 μm), D. castaneicola (10.5–12.8 μm), D. parasiticum (9.3–11.7 μm), D. shaanxiense (9.5–11.1 μm) and D. tianii (9.5–11.1 μm); D. rizhaoense (2.7–3.8 μm) has wider conidia than D. aurorae (2.3–2.6 μm), but narrower conidia than D. shandongense (3.8–4.3 μm) ( Jiang et al. 2019). In addition, D. rizhaoense is similar to D. chinense in conidial size, but differs in the phylogenetical position.

Figures

Figure 1. Maximum likelihood tree generated from combined ITS, tef 1 and rpb 2 sequence data. Bootstrap support values ≥ 50 % and Bayesian posterior probabilities ≥ 0.90 are demonstrated at the branches. Isolates from the present study are indicated in blue, and ex-type strains are marked with *.

Figure 2. Dendrostoma rizhaoense (CAF 800092, holotype) A colony on the PDA plate B, C conidiomata formed on the PDA plate after 28 days D, E conidiogenous cells with attached conidia F – I conidia. Scale bars: 200 µm (B); 100 µm (C); 10 µm (D – I).