Trichothecium roseum (Pers.) Link, Mag. Gesell. Naturf. Freunde, Berlin 3, 18 (1809).
Index Fungorum number: IF152448; MycoBank number: MB152448; Facesoffungi number: FoF07768
Saprobic on Dalbergia cultrata woody litter. Sexual morph: Undetermined. Asexual morph: Colonies on the natural substrate, whitish-salmon becoming rosy, scattered. Conidiophores 96–198 × 2.7–4.1 μm (x̅ = 144 × 3.4 μm, n = 20), simple or branched, hyaline, septate. Conidiogenous cells not observed. Conidia 10.2–19 × 5–10.8 μm (x̅ = 14.4 × 7.6 μm, n = 30; L/W ratio = 1.9), retrogressive modes of conidial development, produced in basipetal chains, hyaline to sub-hyaline, aseptate at immaturity, 1-septate at maturity, slightly constricted at the septum, ellipsoidal to pyriform, mostly obliquely prominent truncated basal scar, abruptly narrowed toward base, rounded at apex, smooth to verrucous, thick-walled. Chlamydospores, when present, hyaline, frequently in intercalary position, smooth-walled.
Culture characteristics – Conidium germinated on PDA within 24 h and a germ tube emerged from one end cell. Colonies on PDA reached 4–5 cm diam. after 9 days at room temperature (25–28 °C), suede-like to powdery, umbonate, with a white ring at the periphery, upper surface white, and reverse yellow at center, buff at periphery.
Material examined – Thailand, Chiang Rai Province, Doi Tung National Park, on dead wood of Dalbergia cultrata (Fabaceae), 26 March 2022, N. Afshari, 6C1T3R1a (MFLU 24-0413); living culture MFLUCC 24-0540.
GenBank numbers – ITS = PQ800245, LSU = PV072600.
Known hosts and distribution – Trichothecium roseum has a cosmopolitan distribution and is associated with different hosts (Farr & Rossman 2025). This study presents the first report of T. roseum on Dalbergia cultrate from Thailand.
Notes – Trichothecium roseum (MFLUCC 24-0540) clustered in a clade containing three strains of T. roseum (DAOM 208997, JKI-GFP-22-010, GYUGC01) with combined ITS, and LSU sequence data (Fig. 60). The characteristics of our strain are consistent with the characters of T. roseum as previously documented (Kwon et al. 2010, Oh et al. 2014, Lin et al. 2016, Harishchandra et al. 2023). Trichothecium roseum is an important post-harvest fungus that causes pink rot and white stain disease in many fruits and vegetables globally; it is also important due to its ability to produce mycotoxins (Harishchandra et al. 2023). This fungus is also associated with decaying plant material and can also be found from soil (Domsch et al. 1993). Trichothecium roseum was reported from many different plant hosts worldwide (Farr & Rossman 2025). Therefore, we propose T. roseum (MFLU 24-0413) as a new host record on dead Dalbergia cultrata wood.
Figure 1 – Phylogram generated from the maximum likelihood analysis based on the combined ITS and LSU sequence data of Trichothecium. Tree topology of the maximum likelihood analysis is similar to the Bayesian analysis. Fifteen strains are included in the combined analyses, which comprised 1,252 characters (ITS = 475, and LSU = 777). The best RAxML tree with a final optimization likelihood value of -2706.902309 is presented. The matrix had 139 distinct alignment patterns, with 14.39% of undetermined characters or gaps. Estimated base frequencies were as follows: A = 0.228017, C = 0.270026, G = 0.298204, T = 0.203753; substitution rates AC = 2.102218, AG = 2.106836, AT = 2.085904, CG = 1.759619, CT = 8.853385, GT = 1.000000; gamma distribution shape parameter α = 0.191047. In the Bayesian analysis, average standard deviation of split frequencies at the end of 1,000,000 MCMC generations was calculated as 0.004002. The evolutionary models TIM2+G and TrN+G were applied to combined ITS and LSU sequence data, respectively. Bootstrap support values for ML greater than or equal to 75% and Bayesian posterior probabilities greater than or equal to 0.90 are given above the nodes. The strain codes are noted after the species names. The tree is rooted with Stromatonectria caraganae (CBS 127387 and CBS 125579). Ex-type strains are in bold. The isolate generated in this study is indicated in bold and blue.
Figure 2 – Trichothecium roseum (MFLU 24-0413, a new host record). Whitish-salmon conidial mass on Dalbergia cultrata woody litter. b, c Colonies on PDA (front and reverse). d–h Conidiophores, conidiogenous cells, and conidia. i–n Conidia. o A germinated conidium. Scale bars: a = 1 mm, d–h, o =20 μm, i–n = 10 μm.