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

Fig. 3

Etymology.

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

Type.

China. Guangdong Province: Futian Mangrove National Nature Reserve , from leaf of Aegiceras corniculatum , July 2020, Z.F. Zhang (Holotype HMAS 352374, culture ex-type CGMCC 3.24353 = LC19369) .

Other material examined.

China. Guangdong Province: Futian Mangrove National Nature Reserve , from leaf of Aegiceras corniculatum , July 2020, Z.F. Zhang (Holotype HMAS 352375, culture ex-type CGMCC 3.24354 = LC19370) .

Description.

Sexual morph: unknown. Asexual morph: Mycelium consisting of branched, septate, hyaline to pale brown, smooth, and thick-walled hyphae. Conidiophores arising from the aerial hyphae or hyphal ropes, continuous or septate, usually reduced to conidiogenous cells, 0(-1)-septate. Conidiogenous cells solitary, hyaline to pale brown, smooth, subcylindrical, straight to geniculous-sinuous, thick-walled, 7.5-24 × 1.5-2.5 µm, bearing a few conidia near the apex. Conidia smooth-walled, subhyaline to pale brown, ellipsoidal or cylindrical, tapering torwards the base, mostly 1-septate, rarely 2-3-septate, sometimes constricted at the septum, 8-15(-26.5) × 2.5-3.5(-6.5) µm (av. ± SD = 9.3 ± 1.16 × 2.83 ± 0.26 µm, n = 40).

Culture characteristics.

Colonies reaching up to 20-22 mm diam after 14 days at 25 °C, dense aerial mycelium on MEA and OA. On MEA, smooth to felty, dry, surface greyish brown to dark brown, reverse saddle brown. On OA, surface ivory to peru, reverse brown black.

Notes.

Scolecobasidium aegiceratis is phylogenetically related to S. dracaenae (Fig. 1 ) and can be differentiated from the later by DNA sequences of LSU (99.52% similarity), ITS (93.55%) and tef1 -α (96.60%) regions. Morphological characters of the two species are overlapping but their conidiophores and conidia show differences. Scolecobasidium aegiceratis can be distinguished from S. dracaenae as it produces hyaline to pale brown (vs. brown in S. dracaenae ) conidiogenous cells. In addition, the dimensions of their conidia (8-15(-26.5) × 2.5-3.5(-6.5) µm vs. 6.5-10 × 3-4 μm) and conidiogenous cells (7.5-24 × 1.5-2.5 µm vs. 5-15 × 2.5-3 μm) are different ( Crous et al. 2016).

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 3. Scolecobasidium aegiceratis (ex-type CGMCC 3.24353) A, B leaf spots of Aegiceras corniculatum C, D forward and reverse colony on OA after 14 days E, F forward and reverse colony on MEA after 14 days G-I conidiophores, conidiogenous cells and conidia J-M conidia. Scale bars: 10 μm (G-M).