Dendrostoma tianii 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 tianii Ning Jiang sp. nov.

Fig. 3

Etymology.

Named after the Chinese taxonomist Prof. Dr. Tian Chengming.

Holotype.

CAF 800093 .

Description.

Sexual morph: Pseudostromata erumpent, consisting of an inconspicuous ectostromatic disc, semi-immersed, causing a pustulate bark surface, 800–1750 µm diam. Ectostromatic disc flat or concave, brown, sometimes concealed by ostioles, surrounded by bark flaps, 350–750 µm diam.; central column yellowish to brownish. Stromatic zones lacking. Perithecia conspicuous, umber to fuscous black, 300–450 µm diam. Ostioles 4–9 per disc, flat in the disc or sometimes slightly projecting, cylindrical, covered by an orange, umber to fuscous black crust, 55–80 µm diam. Paraphyses slightly deliquescent. Asci fusoid to slightly fusiform, 8 - spored, ascospores regularly disposed, with an apical ring, 55–75 × 13–16.5 µm. Ascospores hyaline, fusoid to cylindrical, smooth, straight, bicellular, (17.5 –) 18.7–22.1 (– 23.8) × (4.6 –) 5.4–6.8 (– 7) μm, l / w = (2.8 –) 3–3.7 (– 4.1) (n = 50), with a hyaline, subconical to filiform appendage 5.5–8.5 × 2–2.5 μm at each end. Asexual morph: Conidiomata formed on host barks acervular, conical to pulvinate, occurring separately, pale brown, immersed to semi-immersed, 300–400 μm high, 250–350 μm diam.; wall of several layers of faint yellow textura angularis; central column beneath the disc, yellow. Conidiogenous cells lining the inner walls of the cavity, hyaline, smooth, subcylindrical, 6.5–10.5 × 2.5–5 μm. Conidia hyaline, aseptate, smooth, multiguttulate, thin-walled, ellipsoid, straight or slightly curved, (8.1 –) 9.5–11.1 (– 12.2) × (2.5 –) 2.6–3.2 (– 3.4) μm, l / w = (3 –) 3.2–4.1 (– 4.6) (n = 50).

Culture characteristics.

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

Materials examined.

China • Shandong Province, Rizhao City, Wulian County, Songbai Town , on cankered branches of Castanea mollissima , 15 July 2023, Jiang Ning ( CAF 800093 , holotype); ex-type culture CFCC 58140 • Shandong Province, Rizhao City, Wulian County, Shichang Town , on cankered branches of C. mollissima , 15 July 2023, Jiang Ning ( BL 013 ); culture CFCC 58141 .

Notes.

Dendrostoma tianii is phylogenetically close to D. shaanxiense (Fig. 1 ). These two species share the same host Castanea mollissima , and are both distributed in China; D. tianii in Shandong Province, while D. shaanxiense in Shaanxi Province. In addition, they have similar conidia in shape and size. However, they are distinguished by sequence data (nucleotide differences in the ITS: 25 / 400 (6.25 %), 7 insertion; in tef 1: 9 / 400 (2.25 %), 7 insertion) ( Jiang et al. 2019).

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 3. Dendrostoma tianii (CAF 800093, holotype) A a diseased Chinese chestnut tree B habit of psedostromata C transverse section through the pseudostroma D habit of a conidioma E transverse section through the conidioma F colony on the PDA plate G conidiomata formed on the PDA after 28 days H, I ascus J – L ascospores M conidiogenous cells with attached conidia N conidia. Scale bars: 1000 µm (B, C); 200 µm (D); 300 µm (E); 500 µm (G); 10 µm (H – N).