Colletotrichum castaneae Y. Q. Yang, Q. Zhang, K. D. Hyde & Yong Wang bis

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 castaneae Y. Q. Yang, Q. Zhang, K. D. Hyde & Yong Wang bis , in Zhang et al., Mycosphere 14 (2): 24 (2023)

Figs 2 , 6

Description.

Associated with leaf spots of Jasminum grandiflorum . Leaf spots irregular, pale brown to brown. Sexual morph: Not observed. Asexual morph on PDA: Conidiomata 150–500 µm diam. (x ̄ = 250 µm, n = 5), semi-immersed, scattered or segregated, globose to subglobose, dark brown to black, exuding glistening yellowish to orange conidial mass. Setae not observed. Conidiophores hyaline. Conidiogenous cells 6.5–28 × 2–5 µm (x ̄ = 18.6 × 3.1 µm, n = 10), hyaline, cylindrical to ampulliform, solitary or branched, straight or flexuous, tapering towards the apex. Conidia 13.5–19.5 × 4–6 µm (x ̄ = 16.1 × 5 µm, n = 30; L / W ratio = 3.2), hyaline, cylindrical, straight, smooth-walled, guttulate, aseptate, mostly with rounded ends. Appressoria not observed.

Culture characteristics.

Colonies on PDA reaching approximately 65 mm diam. after 7 d of incubation at 25 ° C; mycelium initially white, becoming yellowish to olivaceous brown with age; elevation flat, aerial, and filamentous with an entire or undulate margin.

Specimens examined.

Thailand • Chiang Mai Province, Doi Inthanon National Park, Kew Mae Pan nature trail , associated with leaf spots of Jasminum grandiflorum ( Oleaceae ), 20 Oct 2021, D. Gomdola DGJas 3 (L 6) - C ( MFLU 25-0003 , BHH 50477 ), living culture MFLUCC 25-0004 ; DGJas 3 (L 9) - B ( MFLU 25-0004 , BHH 50479 ), living culture MFLUCC 25-0005 .

GenBank accession numbers.

MFLUCC 25-0004 ; ITS = PV 263291; GAPDH = PV 290897; CHS 1 = PV 274248; ACT = PV 297874; and TUB 2 = PV 295617; MFLUCC 25-0005 ; ITS = PV 263292; GAPDH = PV 290898; CHS 1 = PV 274249; ACT = PV 297875; and TUB 2 = PV 295618.

Known hosts, distributions, and lifestyles.

Associated with leaf spots of Castanea mollissima in China ( Zhang et al. 2023 a) and Jasminum grandiflorum in Thailand (this study).

Notes.

Based on the phylogenetic analyses, our isolates ( MFLUCC 25-0004 and MFLUCC 25-0005 ) grouped with 100 % ML and 1.00 PP support. This sub-clade grouped with Colletotrichum castaneae ( GUCC 21268.4 , GUCC 12179 , and GUCC 12176 ) with 100 % ML and 1.00 PP support (Fig. 2 ). As per our findings, C. castaneae is located within the C. gloeosporioides species complex (Figs 1 , 2 ), consistent with the study of Zhang et al. (2023 a). No nucleotide differences were observed in the ITS region (526 bp) between our isolates and C. castaneae ( GUCC 21268.4 ). The following sequence divergences were noted across other regions: 0.4 % in GAPDH (1 / 228 bp), 0.9 % in ACT (2 / 231 bp), 1.3 % in CHS 1 (3 / 225 bp), and 0.6 % in TUB 2 (3 / 495 bp).

MFLUCC 25-0004 and MFLUCC 25-0005 morphologically resemble the ex-type of C. castaneae ( GUCC 21268.4 ) with hyaline, ampulliform to obclavate conidiogenous cells and hyaline, aseptate, smooth-walled, and cylindrical conidia, mostly with rounded ends ( Zhang et al. 2023 a). The conidial L / W ratio of our isolates is also similar to that of C. castaneae ( GUCC 21268.4 ) (L / W ratio = 3.4 vs. 3.2).

Based on phylogenetic and morphological species concepts, we identify our isolates as Colletotrichum castaneae . This study represents the first report of C. castaneae associated with leaf spots on Jasminum grandiflorum 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 2. 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 2, which includes all species in the C. gloeosporioides 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. beeveri (CBS 128527) and C. boninense (CBS 123755), belonging to the C. boninense 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 6. Colletotrichum castaneae. a. Leaf spots (Jasminum grandiflorum); b, c. Top and reverse of colony on PDA after 3 d d Conidiogenesis and developing conidia; e, f. Conidia. Scale bars: 10 μm.