Arboricolonus simplex S.Bien & Damm, 2020

Bien, Steffen & Damm, Ulrike, 2020, Arboricolonus simplex gen. et sp. nov. and novelties in Cadophora, Minutiella and Proliferodiscus from Prunus wood in Germany, MycoKeys 63, pp. 119-161 : 119

publication ID

https://dx.doi.org/10.3897/mycokeys.63.46836

persistent identifier

https://treatment.plazi.org/id/23BEFC07-66A4-5946-8E10-246CAFFDAFB0

treatment provided by

MycoKeys by Pensoft

scientific name

Arboricolonus simplex S.Bien & Damm
status

sp. nov.

Arboricolonus simplex S.Bien & Damm sp. nov. Figures 5A View Figure 5 , 6 View Figure 6

Type.

Germany, Saxony, orchard north of Wölkau, 50°58'42.3"N, 13°49'40.0"E, from brown wedge-shaped necrosis in wood of Prunus domestica , 16 Jan 2015, S. Bien leg., GLM-F106309 - holotype; GLMC 459 = CBS 145520 = DSM 109147 - culture ex-type.

Etymology.

Named after the simple, reduced conidiophores.

Description.

Sexual morph not observed. Asexual morph on SNA. Vegetative mycelium hyaline, smooth-walled, septate, branched, 1-3 µm wide, sometimes hyphal cells inflated and constricted at the septa, chlamydospores absent. Sporulation abundant, conidia formed on hyphal cells. Conidiophores reduced to conidiogenous cells. Conidiogenous cells enteroblastic, hyaline, smooth-walled, integrated or terminal, discrete phialides, ampulliform to navicular, 4-7 × 2-3 μm, often reduced to small necks or openings on hyphae, opening 0.5-1 µm wide, collarettes short tubular to funnel-shaped, 0.5-1 µm long, periclinal thickening sometimes visible. Conidia aggregated in heads or slimy masses around hyphae, hyaline, smooth-walled, aseptate, straight to ± curved, cylindrical, elongate ovoidal to allantoid, with one end rounded, the other end rounded to truncate, 3-4(-4.5) × 1-1.5(-2) µm, mean ± SD = 3.6 ± 0.6 × 1.3 ± 0.2 µm, L/W ratio = 2.8.

Culture characteristics.

Colonies on OA flat to slightly raised with an entire to undulate margin, hyaline, whitish to buff, lacking aerial mycelium, reverse same colours, 2-4 mm diam. in 2 wk, 6-10 mm diam. in 4 wk; on SNA flat to slightly raised with an entire to undulate margin, hyaline to whitish, lacking aerial mycelium, reverse same colours, 1-2 mm diam. in 2 wk, 3-6 mm diam. in 4 wk.

Notes.

The morphology of Arboricolonus simplex is reminiscent of collophorina-like species regarding the colonies that are slow growing, the lack of aerial mycelium and the conidiogenous cells that are mostly reduced to short necks or openings with collarettes on hyphae ( Damm et al. 2010; Bien et al. 2020). In contrast to these genera, microcyclic conidiation has not been observed in Arboricolonus . This genus belongs to the Leotiomycetes as well; however, it is not closely related to Collophorina and collophorina-like genera ( Phacidiales ) treated by Bien et al. (2020). A class-wide phylogenetic analysis of LSU-ITS places it within the order Helotiales (data not shown).

A blastn search with the ITS sequence of A. simplex in GenBank resulted in uncultured and unidentified strains with ≤ 92% identity, for example, an uncultured Helotiales clone from soil in the USA (HQ021771, JH Vineis et al., unpubl. data), while the closest matches with strains, identified at least to the genus level, were strains of Glutinomyces vulgaris with 90% identity (e.g. LC218288; Nakamura et al. 2018). The closest matches in a blastn search with the LSU sequence were, with ≤ 97% identity, the ex-type strain of Hyalodendriella betulae (EU040232; Crous et al. 2007), a strain identified as Chalara aurea (MH872551; Vu et al. 2019) and strains belonging to Polyphilus sieberi (e.g. MG719708; Ashrafi et al. 2018).