Colletotrichum schimae F. Liu, W. P. Wu & L. Cai

Gomdola, Deecksha, Jeewon, Rajesh, McKenzie, Eric H. C., Jayawardena, Ruvishika S., Al-Otibi, Fatimah, Tang, Xia, Wang, Yong, Hyde, Kevin D. & Fu, Li, 2025, Phylogenetic diversity of Colletotrichum species (Sordariomycetes, Glomerellales, Glomerellaceae) associated with plant diseases in Thailand, MycoKeys 119, pp. 137-195 : 137-195

Colletotrichum schimae F. Liu, W. P. Wu & L. Cai , in Liu et al. Stud. Mycol. 101: 38 (2022)

Figs 4 , 5

Description.

Associated with leaf spots of Jasminum sp. Leaf spots circular, pale brown to brown. Sexual morph: Not observed. Asexual morph on PDA: Conidiomata 200–1000 µm diam. (x ̄ = 400 µm, n = 10), semi-immersed, scattered or segregated, globose to subglobose, dark brown to black, exuding glistening yellowish to orange conidial mass. Setae not observed. Conidiophores formed directly from mycelium, hyaline, sometimes septate. Conidiogenous cells 16–45 × 2–4.5 µm (x ̄ = 32 × 3.5 µm, n = 10), formed terminally or laterally on hyphae, hyaline, cylindrical, solitary or branched, straight or flexuous, tapering towards the apex. Conidia 9–15 × 2.5–4 µm (x ̄ = 11.5 × 3.5 µm, n = 30; L / W ratio = 3.3), hyaline, cylindrical to fusiform, smooth-walled, guttulate, aseptate, mostly with acute ends. Appressoria not observed.

Culture characteristics.

Colonies on PDA reaching approximately 40 mm diam. after 7 d of incubation at 25 ° C; mycelium initially white, becoming yellowish to olivaceous brown with age; elevation flat, with an entire margin.

Specimens examined.

Thailand • Chiang Mai Province, Doi Inthanon National Park, Kew Mae Pan nature trail , associated with leaf spots of Jasminum sp. ( Oleaceae ), 20 Oct 2021, D. Gomdola DGJas 1 (L 2) - A ( MFLU 25-0001 , BHH 50476 ), living culture MFLUCC 25-0002 ; DGJas 1 (L 3) - B ( MFLU 25-0002 , BHH 50478 ), living culture MFLUCC 25-0003 .

GenBank accession numbers.

MFLUCC 25-0002 ; ITS = PV 263289; GAPDH = PV 290895; CHS 1 = PV 274246; ACT = PV 297872; and TUB 2 = PV 295615; MFLUCC 25-0003 ; ITS = PV 263290; GAPDH = PV 290896; CHS 1 = PV 274247; ACT = PV 297873; and TUB 2 = PV 295616.

Known hosts, distributions, and lifestyles.

Endophytic on Schima sp. in China ( Liu et al. 2022).

Pathogenic on leaves of Camellia sinensis var. assamica and Ilex chinensis in China ( Sui et al. 2024).

Associated with leaf spots of Jasminum sp. in Thailand (this study).

Notes.

Our isolates ( MFLUCC 25-0002 and MFLUCC 25-0003 ) grouped with Colletotrichum schimae ( LC 13880, LC 13881, PC 9, CNUCC 324 C- 1-5 - 2, and CNUCC 528-2 - 2) with 97 % ML and 0.98 PP support (Fig. 4 ). In our phylogenetic analyses, C. schimae is positioned within the C. acutatum species complex (Figs 1 , 4 ), consistent with the findings of Liu et al. (2022) and Sui et al. (2024). Nucleotide sequence comparisons between our two isolates and C. schimae ( LC 13880) showed no differences in ITS (494 base pairs, bp), GAPDH (215 bp), and TUB 2 (490 bp) regions. However, a 0.8 % sequence divergence (2 / 245 bp) was observed in the CHS 1 gene between our isolates and the ex-type of C. schimae ( LC 13880). For ACT, no differences were found between MFLUCC 25-0002 and C. schimae ( LC 13880), but a 1.9 % divergence (4 / 208 bp) was observed between MFLUCC 25-0003 and C. schimae ( LC 13880).

MFLUCC 25-0002 and MFLUCC 25-0003 morphologically resemble the ex-type of C. schimae ( LC 13880) with hyaline, cylindrical conidiogenous cells and hyaline, smooth-walled, guttulate, and cylindrical to fusoid conidia with acute ends ( Liu et al. 2022). Additionally, the conidial length-to-width ratio (L / W) of our isolates is similar to that of C. schimae ( LC 13880) (L / W ratio = 3.3 vs. 3.3).

Based on phylogenetic and morphological species concepts, we identify our isolates as Colletotrichum schimae . This study represents the first report of C. schimae associated with leaf spots on Jasminum sp. and establishes a new geographical record in Thailand.

Figures

Figure 1. Maximum likelihood analysis (IQ-tree) based on a combined dataset of ITS, GAPDH, CHS 1, ACT, TUB 2, H 3, and CAM sequences from dataset 1, which includes all Colletotrichum species. Bootstrap support values (ML ≥ 80 %) and Bayesian posterior probabilities (PP ≥ 0.95) are given above the branches or near the nodes as ML / PP. Hyphens (--) indicate bootstrap support values below 80 % for ML and posterior probabilities below 0.95. The tree is rooted with Monilochaetes infuscans (CBS 869.96) and M. melastomae (CBS 145059). Type, ex-type, and reference species are denoted with T. Our isolates are in bold red font, while our new species are in bold blue font. Different color blocks represent distinct species complexes, with a single color used to denote singleton species.

Figure 4. Maximum likelihood analysis (IQ-tree) based on a combined dataset of ITS, GAPDH, CHS 1, ACT, TUB 2, H 3, and CAM sequences from dataset 4, which includes all species in the Colletotrichum acutatum species complex. Bootstrap support values (ML ≥ 80 %) and Bayesian posterior probabilities (PP ≥ 0.95) are given above the branches or near the nodes as ML / PP. Hyphens (--) indicate bootstrap support values below 80 % for ML and posterior probabilities below 0.95. The tree is rooted with C. dematium (CBS 125.25) and C. parthenocissicola (MFLUCC 17-1098), belonging to the C. dematium species complex. Type, ex-type, and reference species are denoted with T. Our isolates are in bold red font. Different color blocks represent distinct species complexes.

Figure 5. Colletotrichum schimae. a. Leaf spots (Jasminum sp.); b. Top and reverse of colony on PDA after 7 d; c. Conidiogenesis and developing conidia; d – i. Conidia. Scale bars: 10 μm. The scale bar (i) applies to d – h.