Dinemasporium pseudostrigosum Crous, Persoonia

Goonasekara, Ishani D., Jayawardena, Ruvishika S. & Saichana, Natsaran, 2022, New records of two appendage bearing ceolomycetes on grasses in Thailand, Phytotaxa 541 (2), pp. 113-128 : 120-121

Dinemasporium pseudostrigosum Crous, Persoonia 28: 134 (2012)

Index Fungorum number: IF 800164; Facesoffungi number: FoF 07316 ( Fig. 3 )

Saprobic on culms of dead grass. Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata 60–100 × 120–150 µm (x = 80 × 135 μm, n = 15), stromatic, brown to black, superficial, solitary to gregarious, occasionally confluent, pulvinate, oval to rounded in outline, cupulate, with incurved margins, unilocular, setose. Conidiomatal setae 200–250 µm long, 3–5 µm wide, arising from the basal stroma, straight or curved, septate, brown but pale at the apex, thick-walled, acute, unbranched. Conidiomatal wall 8–10 µm wide, of textura angularis with cells brown to pale brown, thick-walled. Conidiophores lining the basal stroma, rectangular to cylindrical, smooth, pale brown to hyaline, unbranched. Conidiogenous cells 6–11 × 2–3 µm (x = 9 × 2.3 μm, n = 20), phialidic, subcylindrical to lageniform, hyaline, smooth. Conidia 8–10 × 2–3.5 μm (x = 9 × 3 μm, n = 40), hyaline, naviculate to fusiform or ellipsoid, obtuse or slightly acute at the apex, slightly truncate at the base, unicellular, eguttulate or guttulate, smooth, bearing 3–6 µm long, unbranched, single tubular appendage at each end.

Culture characteristics:— Colonies on PDA reaching 4–5 cm diam. after 2 weeks at 28–30 °C, medium sparse, irregular, slightly raised, surface smooth with undulate edge, fairly fluffy and strongly irregular, wrinkled, folded margins, colony from above white, reverse pale yellow becoming greyish brown just surrounding the center as the colony matures, grey to pale yellow at the margins, no pigmentation observed.

Known hosts:— Bamboo species, dead grass ( Poaceae ), Elymus farctus (Poaceae) , Stigmaphyllon sagraeanum (Malpighiaceae) ( Crous et al. 2012, Hashimoto et al. 2015, Li et al. 2020, this study).

Known distribution:— Germany, Italy, Japan, Thailand ( Crous et al. 2012, Hashimoto et al. 2015, Li et al. 2020, this study).

Material examined:— THAILAND. Chiang Mai Province: Mae Teang District, Mushroom Research Center ( M. R. C.), on dead culms of unidentified grass ( Poaceae ), 24 March 2016, Ishani D. Goonasekara, IGm34 ( MFLU 22-0006 , new geographical record), living culture MFLUCC 16-0894 ; ibid., on dead culms of unidentified grass ( Poaceae ), 28 March 2016, Ishani D. Goonasekara, IGm38 ( MFLU 22-0007 ), living culture MFLUCC 16-0896 .

Notes:— According to the phylogenetic tree ( Fig. 1 ), our isolates (MFLUCC 16-0894 and MFLUCC 16-0896) are identified as Dinemasporium pseudostrigosum . This taxon was originally described in Crous et al. (2012) from Triticum aestivum in Germany. Our new isolates cluster with D. pseudostrigosum isolates (CBS 717.85, CBS 825.91 and MFLU 15-0588) in a strongly supported clade (81% ML, 91%, 0.99 BYPP). In particular, they have a close relationship with the strain CBS 825.91 showing high statistical support (76% ML, 71% MP, 0.97 BYPP). Morphologically, our collections resemble D. pseudostrigosum (CBS 717.85, CBS 825.91) in having stromatic, brown to black, superficial, unilocular, setose conidiomata, subcylindrical to lageniform conidiogenous cells and naviculate to fusiform or ellipsoid, aseptate, hyaline conidia with tubular appendages at each end ( Crous et al. 2012). However, our collections have slightly smaller conidia (8–10 × 2–3.5 μm) than the type species (12–13 × 3 μm) ( Crous et al. 2012). Herein, we introduce our collection as a new geographical record of D. pseudostrigosum for Thailand.

Figures

FIGURE 1. RAxML tree based on a combined dataset of LSU and ITS partial sequences of 39 taxa of the family Chaetosphaeriaceae. Bootstrap support values for maximum likelihood (ML), maximum parsimony (MP) values higher than 65% and Bayesian posterior probabilities (BYPP) greater than 0.90 are given above each branch, respectively. The new isolates are in red. Ex-type strains are in bold typeface. The tree is rooted to Menispora tortuosa (AFTOL-ID 278 and CBS 214.56).

FIGURE 3. Dinemasporium pseudostrigosum (MFLU 22-0006). a, b. Appearance of conidiomata on host. c. Close-up of conidioma. d. Squash mount of conidioma with seta. e. Section of conidioma. f. Conidiomatal wall. g, h. Conidiogenous cells and developing conidia. i–l. Conidia. Scale bars: b, c = 500 µm, d, e = 50 µm, g, h = 2 µm, f, i–l = 5 µm.