Lasiodiplodia thailandica Trakun., L. Lombard & Crous, Persoonia 34: 95 (2014)

Index Fungorum number: IF 810169; Mycobank number: MB 810169; Facesoffungi number: FoF 09333, Fig. 2

Saprobic on dead leaves of Celtis tetrandra Roxb. (Cannabaceae). Sexual morph: Not observed. Asexual morph: Coelomycetous. Conidiomata 150–250 µm high, 200–300 µm diam., pycnidial, semi-immersed, becoming erumpent, solitary or gregarious, brown to black, globose to subglobose, uniloculate, ostiolate. Conidiomatal wall 15–20 μm, consisting of 4–5 layers, thin-walled, of equal thickness, pale brown to dark brown pseudoparenchymatous cells, cells towards the inside light brown, arranged in a textura angularis, fusing and indistinguishable from the host tissues. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 7–10×2–4 μm (x̄=8×3 μm, n=30),
hyaline, smooth, thin-walled, discrete, cylindrical, holoblastic, proliferating percurrently from hyaline inner conidiomatal wall. Conidia 22–26×12–14 μm (x̄=24×13 μm), initially hyaline, turning pale brown at maturity, aseptate, with a single median septum and longitudinal striations after discharge from the pycnidia, oblong to ovoid, straight, both ends broadly rounded, thin-walled.

Culture characteristics – Colonies on PDA reaching 30 mm diam. after 4 days at 20–25 °C, colonies medium sparse, circular, raised, surface slightly rough with entire edge, cottony to fairly fluffy with sparse aspects, colony from above: greenish to grey; reverse: greenish to pale brown. Mycelium whitish grey with tufting; not producing pigments in PDA.

Material examined – China, Chiayi, Fanlu Township area, dead leaves of Celtis tetrandra (Cannabaceae), 11 June 2019, D.S. Tennakoon, GSPD061R (NCYU 19-0402, new host record), living culture, NCYUCC 19-0392.

GenBank Numbers – ITS: OR759966, tub2: OR767663, tef1-α: OR767664

Notes – The morphological characteristics of our collection (NCYU 19-0402) tally well with the type of Lasiodiplodia thailandica in having similar size range of conidiogenous cells (7–10×2–4 μm vs 8–9×2–4 µm), conidia (22–26 × 12–14 μm vs 22–25 × 13–15 μm) and other conidial characters (e.g., initially hyaline, aseptate, turning pale brown with maturity,with a singlemedian septum and longitudinal striations after discharge from the pycnidia, oblong to ovoid) (Trakunyingcharoen et al. 2014). Multigene phylogeny (ITS, tef1-α and tub2) also directs that our collection clustered with L. thailandica species in a well-supported clade (Fig. 1, 80% ML and 1.00 BYPP). Thus, we report our collection as a new host record of L. thailandica from Celtis tetrandra (Cannabaceae).

Figure 1 – The best scoring RAxML tree with a final likelihood value of − 4936.454266 for the combined dataset of ITS, tef1-α and tub2 sequence data. The topology and clade stability of the combined gene analyses were compared to the single gene analyses. The tree is rooted with Diplodia mutila (CMW7060). The matrix had 373 distinct alignment patterns with 17.69% undetermined characters and gaps. Estimated base frequencies were as follows; A=0.208520, C=0.302466, G=0.256954, T=0.232060; substitution rates AC=1.235624, AG=3.293289, AT=1.444962, CG=1.060100, CT=5.061546, GT=1.000000; gamma distribution shape parameter α=0.676319. Ex-type strains are in bold and newly generated sequences are in red. Bootstrap support values for ML equal to or greater than 60% and BYPP equal to or greater than 0.95 are given above the nodes

Figure 2 – Lasiodiplodia thailandica (NCYU 19-0402, new host record) a A dead leaf of Celtis tetrandra. b, c Appearance of conidiomata on host. d Section of conidioma. e Conidioma wall. f Conidiogenous cells with developing conidia. g, h Conidia. i Germinated conidium. j Colony from above. k Colony from below. Scale bars: d=50 µm, e=10 µm, f–i=12 µm