Stagonosporopsis stuijvenbergii Hern.-Restr., L. W. Hou, L. Cai & Crous, 2020

Hou, Lingwei, Hernandez-Restrepo, Margarita, Groenewald, Johannes Zacharias, Cai, Lei & Crous, Pedro W., 2020, Citizen science project reveals high diversity in Didymellaceae (Pleosporales, Dothideomycetes), MycoKeys 65, pp. 49-99 : 49

Stagonosporopsis stuijvenbergii Hern.-Restr., L. W. Hou, L. Cai & Crous sp. nov. Figure 9

Etymology.

stuijvenbergii refers to Simon van Stuijvenberg, who collected the soil sample from which the ex-type strain was isolated.

Typus.

The Netherlands. Gelderland province, Meteren, from garden soil, Mar. 2017, S. van Stuijvenberg (holotype designated here CBS H-24109; living ex-type culture CBS 144953 = JW 132011).

Conidiomata pycnidial, produced on the agar surface, scattered or aggregated, solitary globose to subglobose, or 4-7(-10) confluent and irregularly-shaped, brownish, glabrous, ostiolate, 200-1000 × 195-930 μm; with 1-2 slightly papillate ostioles, sometimes elongated to a short neck; pycnidial wall pseudoparenchymatous, 4-5 layers, 6.5-35 μm thick, outer layers composed of brown, flattened polygonal cells, 9.5-33 μm diam. Conidiogenous cells phialidic, hyaline, smooth, globose, ampulliform or lageniform, 4.5-9 × 4-8 μm. Conidia ellipsoidal to oblong, smooth- and thin-walled, hyaline, aseptate, 3.5-6.5 × 2-3 μm, 1-2-guttulate. Conidial matrix whitish.

Culture characteristics.

Colonies after 7 d at 25 °C, on OA reaching 75-80 mm diam, floccose aerial mycelium, olivaceous to pale olivaceous, whitish to pink near the edge, margin regular; reverse iron grey. On MEA reaching 65-70 mm diam, margin regular, aerial mycelium floccose, vinaceous buff with olivaceous edge; reverse darker brown with olivaceous black edge, buff near the centre. On PDA reaching 70-75 mm diam, margin regular, covered by floccose aerial mycelium, olivaceous, olivaceous black towards periphery, with pinkish to pale brown edge; reverse iron-grey, buff towards periphery. NaOH spot test negative on OA.

Additional specimens examined.

The Netherlands, Gelderland province, Arnhem, from garden soil, Mar. 2017, D. Peters, JW 14003; Utrecht province, Utrecht, from garden soil, Mar. 2017, N. Francisca, JW 44014; Utrecht, from garden soil, Mar. 2017, P. de Koff, JW 33021.

Notes.

Phylogenetically, S. stuijvenbergii is most closely related to S. weymaniae , another novel species collected from Dutch soil in this study (Figure 1 ). However, S. stuijvenbergii is distinguishable from S. weymaniae by the colour and the size of its pycnidia, being brown and measuring 200-1000 × 195-930 μm in S. stuijvenbergii , whereas S. weymaniae produces whitish pycnidia, measuring 330-650 × 250-550 μm. Furthermore, S. weymaniae produces microconidia and chlamydospores, which were not observed in S. stuijvenbergii. Although there are several reports that Stagonosporopsis spp. could survive in soil for a short time ( Vaghefi et al. 2016), this is the first record of a Stagonosporopsis species only known from soil ( Domsch et al. 2007). Stagonosporopsis stuijvenbergii is represented by four strains isolated from different samples collected in Utrecht and Gelderland provinces.

Figures

Figure 1. Phylogenetic tree generated from the maximum-likelihood analysis based on the combined ITS, LSU, tub 2 and rpb 2 sequence alignment of Didymellaceae members. The RAxML bootstrap support values (BS), Bayesian posterior probabilities (PP), and parsimony bootstrap support values (PBS) are given at the nodes (BS / PP / PBS). BS and PBS values represent parsimony bootstrap support values> 50 %. Full supported branches are indicated in bold. The scale bar represents the expected number of changes per site. Ex-type strains are represented in bold. Strains obtained in the current study are printed in green; among them, whilst strains that represent new taxa are printed in red. Some of the basal branches were shortened to facilitate layout (the fraction in round parentheses refers to the presented length compared to the actual length of the branch). The tree was rooted to Coniothyrium palmarum CBS 400.71 and Leptosphaeria doliolum CBS 505.75.

Figure 9. Stagonosporopsis stuijvenbergii (CBS 144953). A, B Colony on OA (front and reverse) C, D colony on MEA (front and reverse) E, F colony on PDA (front and reverse) G pycnidia forming on OA H pycnidia I ostiole J-L conidiogenous cells M stromatic hyphal aggregations N conidia. Scale bars: 50 μm (H); 10 μm (I, M); 5 μm (J-L, N).