Colletotrichum brevisporum Noireung, Phouliv., L. Cai & K.D. Hyde, Cryptog. Mycol. 33(3): 350 (2012)

Index Fungorum number: IF 564156; Mycobank number: MB 564156; Facesoffungi number: FoF 15072; Fig. 1

Associated with anthracnose leaf spot on Melothria sp. Sexual morph Not observed. Asexual morph Conidiomata produced on 32 days old PDA culture, acervular, dark brown, bearing conidial mass. Setae not observed. Conidiophores not observed, Conidiogenous cells hyaline, smooth-walled, cylindrical or clavate, 10–12 × 3.5–5 μm (x̅= 11 × 4.5 µm, n = 10). Conidia hyaline, aseptate, smooth-walled, cylindrical, straight, rounded at ends, guttulate, 15–20 × 5.5–6.5 μm (x̅= 17.5 × 6 µm, n = 30). Appressoria in slide culture, brown to dark brown, variable in shape ovoid or slightly irregular, undulate to slightly lobate, 8–13×7–9 μm, formed by hyphae, becoming complex with age.

Culture characteristics – Colonies on PDA 35 mm after 7 days, cottony, circular, entire in margin; aerial hyphae medium sparse, white, reverse whitish buff. Colonies on OA 35–40 mm after 7 days, flat, entire in margin, surface white, reverse same color.

Material examined – Thailand, Chiang Rai Province, Phan District, Doi Pui Sai Khao Sub-district, on Melothria sp. leaf, 27 September 2021, Alireza Armand, T41 (MFLU 23-0444; MFLUCC 23-0285).

GenBank numbers – ITS: OR793879; act: OR804450; chs1: OR804452; gapdh: OR804454; tub: OR804456

Notes – In the phylogenetic analysis, C. brevisporum strains from this study, clustered with the type strain of C. brevisporum (CBS129958) with 95% ML, 91% MP and 1.0 BYPP values (Fig. 2). Base pair differences between C. brevisporum (MFLUCC 23-0285) and C. brevisporum (BCC 38876) revealed no differences in ITS, chs-1 and tub2, 0.4% (1/258 bp) in act, 0.8% (2/238) differences in gapdh. Morphologically, C. brevisporum (MFLU 23-0444) is similar to C. brevisporum (BCC 38876, holotype) described by Noireung et al. (2012). However, our strain produced bigger conidia (15–20 × 5.5–6.5 μm in C. brevisporum (MFLU 23–0444) vs. 12–17×5–6 μm in the type strain) (Noireung et al. 2012). This is a new host record for the occurrence of C. brevisporum on Melothria.

Figure 1 – Colletotrichum brevisporum (MFLU 23-0444), a, b. Host leaves with symptoms. c. Acervulus and conidial mass on PDA. d, e. Conidiogenous cells. f. Conidia. g–i. Appressoria. j. Upper and reverse view of culture on PDA. Scale bars: d,e=10 µm, f=20 µm, g–i=10 µm

Figure 2 – Phylogenetic tree of Colletotrichum orchidearum and C. magnum species complexes generated by maximum parsimony analysis of combined ITS, act, chs-1, gapdh and tub2 sequence data. The tree was rooted with C. dracaenophilum (CBS 118199) and C. tongrenense (GMBC 0209). Maximum likelihood and Maximum parsimony bootstrap support values≥50% (BT) as well as Bayesian posterior probabilities≥0.90 (PP) are shown respectively near the nodes. Type strains are in bold, and the newly generated isolates are in red