Scolecobasidium acanthi S. Song, L. Cai & F. Liu, 2023

Song, Shuang, Li, Meng, Huang, Jun-En & Liu, Fang, 2023, Two new species of Scolecobasidium (Venturiales, Sympoventuriaceae) associated with true mangrove plants and S. terrestre comb. nov., MycoKeys 96, pp. 113-126 : 113

Scolecobasidium acanthi S. Song, L. Cai & F. Liu sp. nov.

Fig. 2

Etymology.

Named after the host plant Acanthus from which this fungus was isolated.

Type.

China. Guangdong Province: Qi'ao-Dangan Island Provincial Nature Reserve , from leaf of Acanthus ebracteatus , Nov 2019, M. Li, Z.F. Zhang and J.E. Huang (Holotype HMAS 352373, culture ex-type CGMCC 3.24352 = LC19368) .

Description.

Sexual morph: unknown. Asexual morph: Mycelium consisting of branched, septate, hyaline to pale brown, smooth, and thick-walled hyphae. Conidiophores solitary, erect, brown, smooth, arising from superficial hyphae, subcylindrical, straight to geniculous, brown, thick-walled, 0(-2)-septate, 14.5-20.5 × 1.5-2 µm, often reduced to conidiogenous cells, bearing a few conidia near the apex. Conidiogenous cells brown, smooth, 4.5-9.5 × 1.5-2 µm, terminal and lateral on conidiophores, containing several apical, cylindrical denticles. Conidia 1-septate, smooth-walled, subhyaline to pale brown, cylindrical, rarely pyriform, constricted at the septum, 5.5-8.5 × 2.5-4 µm (av. ± SD = 6.9 ± 0.7 × 3.05 ± 0.2 µm, n = 42).

Culture characteristics.

Colonies reaching up to 16-20 mm diam after 14 days at 25 °C, producing dense aerial mycelium on MEA and OA. On MEA, surface wheat to greyish brown, reverse saddlebrown, felty, dry, margins smooth. On OA, surface burlywood to peru, reverse brown black, margins smooth.

Notes.

Although represented by single strain, S. acanthi sp. nov. formed a distinct clade (Fig. 1 ) that was phylogenetically related to S. aegiceratis sp. nov. The two species differ from each other in 820/825 bp (99.39%) in LSU, 474/514 bp (92.22%) in ITS, 525/538 bp (97.58%) in tef1 -α, and 433/464 bp (93.32%) in tub2. Morphologically, S. acanthi sp. nov. differs from S. aegiceratis sp. nov. in the septa number of conidiophores (0-2 vs. 0-1) and the size of conidiogenous cells (4.5-9.5 × 1.5-2 µm vs. 7.5-24 × 1.5-2.5 µm) and conidia (5.5-8.5 × 2.5-4 µm vs. 8-15(-26.5) × 2.5-3.5(-6.5) µm).

Figures

Figure 1. Phylogenetic tree of Scolecobasidium calculated with a maximum likelihood analysis of the combined ITS, LSU, tef 1 - α, and tub 2 sequences alignment. The tree was rooted with Verruconis calidifluminalis (CBS 125818). Bootstrap values (ML> 50 %) and Bayesian posterior probabilities (PP> 0.90) are shown at the nodes in the order of ML / PP. T indicates ex-type strains. The novel taxa and new combination are showed in bold. The scale bar represents the expected changes per site.

Figure 2. Scolecobasidium acanthi (ex-type CGMCC 3.24352) A the habitat of Acanthus ebracteatus B leaf spot on Acanthus ebracteatus C, D forward and reverse colony on OA after 14 days E, F forward and reverse colony on MEA after 14 days G-J conidiophores, conidiogenous cells and conidia K-P conidia. Scale bars: 10 μm (G-P).