Daldinia rubi Y. Y. Wu & C. M. Tian, 2025

Daldinia rubi Y. Y. Wu & C. M. Tian sp. nov.

Fig. 3 View Figure 3

Type.

China • Guizhou Province, Guiyang City, Yunyan District, Qianlingshan Forest Park , 26°36'06"N, 106°41'42"E, on the leaf spots of Rubus idaeus , 26 Jul 2024, C. M. Tian, N. Jiang, S. J. Li, and Y. Y. Wu ( holotype BJFC -S 2543 ). Ex-type culture CFCC 72599 GoogleMaps .

Etymology.

Named after the host genus, Rubus .

Description.

Sexual morph: not observed. Asexual morph: Conidiophores are mononematous or dichotomously branched, displaying a Virgariella - like to Nodulisporium - like branching pattern. Conidiophores smooth to finely roughened, hyaline, aseptate, with 2–3 conidiogenous cells at each terminus, measuring (14 –) 16–36 (– 39) × 2.5–4 (– 7) μm (av. ± S. D. = 27 ± 8.4 × 3.5 ± 1.2 µm, n = 30). Conidiogenous cells terminal or lateral, cylindrical, hyaline to pale yellow, smooth to finely roughened, with flattened base, producing conidia apically, measuring (11.5 –) 13–20.5 × 2–3.5 μm (av. ± S. D. = 16 ± 2.5 × 3 ± 0.4 µm, n = 30). Conidia ellipsoid to dacryoid, hyaline, aseptate, smooth to finely roughened, solitary, mostly flat-based, holoblastic-sympodial, measuring 4.5–8 × 3–4.5 μm (av. ± S. D. = 7 ± 0.8 × 4 ± 0.3 µm, n = 50).

Culture characters.

Colonies showed sparse, cobweb-like mycelium, appearing semi-transparent, pale gray, with small brown central structures. The reverse was pale grayish-brown with scattered black conidial masses. Aerial hyphae were sparse, growing to 60 mm on PDA in 7 days at 25 ° C.

Other material examined.

China • Guizhou Province, Guiyang City, Yunyan District, Qianlingshan Forest Park , 26°36'06"N, 106°41'42"E, on the leaf spots of Rubus idaeus , 26 Jul 2024, C. M. Tian, N. Jiang, S. J. Li and Y. Y. Wu, BJFC -S 2544 , living cultures CFCC 72600 GoogleMaps .

Notes.

Based on multi-locus phylogenetic analysis, the two isolates ( CFCC 72599 , CFCC 72600 ) formed an independent clade with 100 % MP, 100 % ML, and 1.00 BYPP values, clearly distinct from Daldinia ehretiae in the multi-locus analyses (Fig. 1 View Figure 1 ). To further substantiate the recognition of D. rubi as a new species, a comprehensive comparison of asexual morphological traits within the Daldinia genus in China was conducted (Table 3 View Table 3 ). Morphologically, D. rubi can be readily distinguished from D. ehretiae by multi-trait divergence: as shown in Table 3 View Table 3 , D. rubi produces larger conidia (ellipsoid to dacryoid, 4.5–8 × 3–4.5 μm) compared to D. ehretiae (ellipsoid or cylindrical, 4.2–6.6 × 1.7–2.8 μm). For conidiophores, D. rubi has shorter and narrower structures (mononematous or dichotomously branched, 16–36 × 2.5–4 μm) with more conidiogenous cells per terminus (2–3 cells) than D. ehretiae (mononematous or dichotomously branched, 100–210 × 3.1–4.3 μm, 1–2 cells per terminus). Conidiogenous cells of D. rubi are shorter in length (cylindrical or laterally cylindrical, (11.5 –) 13–20.5 × 2–3.5 μm) versus D. ehretiae (cylindrical, 16.8–24.5 × 2.7–4.1 μm). Molecularly, D. rubi also shows clear divergence from D. ehretiae . There is a 12 bp difference in ITS sequences (376 characters, 96.8 % similarity, including one gap) and a 26 bp difference in tub 2 sequences (745 characters, 96.5 % similarity, no gaps). Collectively, the independent phylogenetic position, distinct morphological traits (as detailed in Table 3 View Table 3 for a comparison of asexual characteristics among Daldinia species in China), and molecular divergence confirm that D. rubi represents a new species.