Colletotrichum sagittati K. Y. Jiang & Zhong Li, 2025

Colletotrichum sagittati K. Y. Jiang & Zhong Li sp. nov.

Fig. 6 View Figure 6

Etymology.

Named after the host plant species sagittatum .

Type.

China • Guizhou Province, Kaili City, Bibao Town (26°30'38"N, 107°37'23"E), from leaves of E. sagittatum . 12 Nov, 2024, KY Jiang (holotype HGUP 21490 , ex-holotype culture GUCC 24-0193 ) GoogleMaps .

Description.

Asexual morph: Conidiomata, irregular, orange. Setae not observed. Conidiophores, formed directly on hyphae, usually reduced to conidiogenous cells, laterally. Conidia hyaline, smooth-walled, aseptate, straight, few conidia slightly curved, cylindrical, the apex and base rounded 14.6–17.9 × 4.9–6.8 μm (mean ± SD = 16.0 ± 0.9 × 6.2 ± 0.6 µm, L / W = 2.56). Appressoria single, dark brown, irregularly, a small amount. Sexual morph: Ascomata perithecia, clustered, superficial, spherical, medium to dark brown, covered with sparse Asci unitunicate, 8 – spored, cylindrical or rod-shaped, smooth-surfaced and slightly pointed at the apex, 38.7–70.5 × 11.0–15.7 μm. Ascospores single or multiseriately arranged, aseptate, hyaline, smooth-walled, cylindrical, blunt rounded ends or slightly protruding at one end, 16.0–19.4 × 3.7–5.6 μm (mean ± SD = 17.1 ± 1.0 × 4.8 ± 0.4 μm and L / W ratio = 3.6).

Culture characteristics.

Colonies on PDA flat, with poorly developed aerial mycelium, closely adhered to the medium surface, with numerous ascomata in the centre. Mycelium white, reverse same colour, growth 7 cm in 14 d.

Notes.

Multi-locus phylogenetic analysis indicates that the three strains of C. sagittati formed a distinct branch within the C. boninense species complex (Fig. 4 View Figure 4 ). Every locus sequenced for these species differed from currently recognised Colletotrichum species. A BLASTn search of C. epimedii sequences in the NCBI GenBank revealed low similarity to other species. The highest similarities for cal, act, chs- 1, GADPH, his 3, ITS and tub 2 were found with C. hippeastri CSSG 1 (92.01 %), C. karsti AGMy 0178 (92.54 %), C. chamaedorea LC 13867 (98.34 %), C. bromeliacearum LC 13855 (77.78 %), C. liriopes HZ- 1 (91.30 %), C. boninense INBio- 275813 (97.96 %) and C. karsti BRIP (91.76 %). In morphology, they can be distinguished from Colletotrichum hippeastri by its smaller conidia (14.6–17.9 × 4.9–6.8 vs. 19–37.5 × 5.5–8.5) ( Damm et al. 2012). Additionally, C. sagittati produces greater conidia than Colletotrichum bromeliacearum (14.6–17.9 × 4.9–6.8 vs. 8.5–16 × 5–7.5) ( Liu et al. 2022). Based on the integrated molecular phylogenetics and morphology, C. sagittati was identified as a new species.