Robillarda africana Crous & Giraldo López, IMA Fungus

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 : 121-122

Robillarda africana Crous & Giraldo López, IMA Fungus 6(1): 184 (2015)

Index Fungorum number: IF 812797; Facesoffungi number: FoF 10700 ( Fig. 4 )

Saprobic on grass litter. Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata 100–140 × 170–230 µm (x = 125 × 190 μm, n = 20), pycnidial, scattered, globose to subglobose, semi-immersed, unilocular, dark brown to black, ostiolate. Conidiomatal wall 30–40 µm, brown to dark brown, arranged in a textura angularis, cells towards the inside hyaline, at the outside darker, fusing and indistinguishable from the host tissues. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 4–5 × 2–3 µm (x = 4.5 × 2.5 μm, n = 20), phialidic, ampulliform to subcylindrical, hyaline, smooth, guttulate, deliquescing at maturity. Conidia 10–12 × 1.5–3 µm (x = 11 × 2.2 μm, n = 30), cylindrical to fusiform, straight or slightly curved, 1-septate, slightly constricted at median septum, hyaline to pale brown, rounded at both ends, smooth-walled, 3 extracellular appendages, 11–16 µm long, arising from the conidial apex.

Culture characteristics:— Colonies on PDA reaching 35 mm diam. after 15 days at 28–30 °C, medium to medium sparse, circular, flat, dull, entire, thinly hairy, slightly irregular margins, smooth, colony from above olive to dark grey at the center, with pale grey to white margins, reverse darker grey, punctiform-like at the center, with greyish and pale yellowish middle area and white margins, no pigmentation observed.

Material examined:— THAILAND. Chiang Mai Province: Mae Teang District, Mushroom Research Center ( M. R. C.), on dead culms of unidentified grass ( Poaceae ), 18 March 2016, Ishani D. Goonasekara, IGm25 ( MFLU 22- 0005 , new host and geographical record), living culture MFLUCC 16-0888 .

Known hosts:— dead grass ( Poaceae ) (this study).

Known distribution:— South Africa, Thailand ( Crous et al. 2015, this study).

Notes:— As morphological characters examined largely overlap with those of Robillarda africana ( CBS 122.75), we report our collection ( MFLUCC 16-0888) as a new host and geographical record of R. africana from dead grass in Thailand. Robillarda africana ( CBS 122.75) was initially introduced by Crous et al. (2015) from South Africa (exact location and substrate unknown). Both isolates ( MFLUCC 16-0888 and CBS 122.75) have pycnidial, globose to subglobose, semi-immersed, unilocular conidiomata, ampulliform to subcylindrical, hyaline conidiogenous cells (4–5 × 2–3 µm vs 3–10 × 2–4 µm) and cylindrical to fusiform, straight or slightly curved, 1-septate, hyaline to pale brown conidia (10–12 × 1.5–3 µm vs 11–12 × 2.5–3 µm) with extracellular appendages ( Crous et al. 2015). Phylogeny also shows that our collection clusters with R. africana ( CBS 122.75) with strong support (96% ML, 89% MP, 1.00 BYPP, Fig. 2 ).

Figures

FIGURE 2. RAxML tree based on a combined dataset of LSU and ITS partial sequences of 40 taxa of the family Sporocadaceae.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 Phlogicylindrium eucalyptorum (CBS 111689) and P. uniforme (CBS 131312).

FIGURE 4. Robillarda africana (MFLU 22-0005). a, b. Appearance of conidiomata on host. c. Close-up of conidiomata. d, e. Sections of conidiomata. f. Conidiomatal wall. g. Conidiogenous cells and developing conidia. h–k. Conidia. Scale bars: a = 1 mm b = 500 µm, c = 200 µm, d, e = 50 µm, f = 10 µm, g = 2 µm, h–k = 5 µm.