Colletotrichum juglandium Y. X. Li & X. L. Fan, 2024

Li, Yixuan, Lin, Lu, Cao, Jing, Gan, Mingxu & Fan, Xinlei, 2024, Three new species of Colletotrichum (Glomerellales, Glomerellaceae) associated with walnut (Juglans regia) anthracnose from China, MycoKeys 108, pp. 147-167 : 147-167

Colletotrichum juglandium Y. X. Li & X. L. Fan sp. nov.

Fig. 7

Etymology.

Named after the host genus on which it was collected, Juglans regia L.

Typification.

China. Sichuan Province, Guangyuan City, Chaotian District , Mianguang Expressway , 32 ° 40 ' 50 " N, 105 ° 59 ' 19 " E, from leaf of Juglans regia L., 10 Oct. 2023, Y. X. Li, L. Lin & X. L. Fan (holotype BJFC - S 2243 , ex-holotype culture CFCC 59974 ) .

Description.

Sexual morph not observed. Asexual morph on OA. Conidiomata acervular, color ranged from peach to light brown. Appressoria and Setae not observed on OA. Conidiophores hyaline, unbranched, approximately cylindrical, 16.0–27.6 × 2.2–4.7, mean ± SD = 20.1 ± 3.2 × 3.2 ± 0.6 µm, n = 30. Conidiogenous cells transparent, cylindrical, formed at the end or side of the hyphae. Conidia straight, hyaline, cylindrical, obtuse at the base, rounded at the apex, with smooth walls and granular contents, 13.2–22.4 × 4.4–6.3 µm, mean ± SD = 16.8 ± 1.8 × 5.4 ± 0.4 µm, L / W radio = 3.1, n = 50.

Culture characteristics.

Colonies on OA initially white, rapidly growing to 5 cm after 3 d at 25 ° C, and completely covering a Petri dish after 7 days. The aerial mycelium white or gray, with a flocculent cotton like, edge white, center mouse grey.

Additional material examined.

China. Sichuan Province, Guangyuan City, Chaotian District , Mianguang Expressway , 32 ° 40 ' 36 " N, 105 ° 59 ' 26 " E, from leaf of Juglans regia L., 10 Oct. 2023, Y. X. Li, L. Lin & X. L. Fan ( BJFC - S 2245 , living culture CFCC 70165 ) .

Notes.

Colletotrichum juglandium form a solitary clade the C. gloeosporioides species complex (Fig. 3 ). Colletotrichum juglandium is closely related to C. citrulli , C. gloeosporioides , C. juglandicola and C. peakense ( Zhang et al. 2023 a) . Sequence identity comparisons reveal that C. juglandium CFCC 59974 differs from other species at various loci: C. citrulli CGMCC 3.20769 (3 / 544 in ITS, 0 / 244 in act, 0 / 228 in chs 1, 10 / 297 in gapdh, and 0 / 324 in tub 2), C. gloeosporioides IMI 356878 (2 / 544 in ITS, 0 / 289 in act, 0 / 236 in chs 1, 18 / 341 in gapdh, and 0 / 324 in tub 2), C. juglandicola CGMCC 3.24312 (2 / 544 in ITS, 0 / 279 in act, 1 / 249 in chs 1, 18 / 341 in gapdh, and 1 / 324 in tub 2), and C. peakense CGMCC 3.24308 (2 / 544 in ITS, 0 / 279 in act, 1 / 249 in chs 1, 13 / 341 in gapdh, and 1 / 324 in tub 2) ( Guo et al. 2022; Yu et al. 2022; Zhang et al. 2023 a). Morphologically, C. juglandium differs from C. gloeosporioides by having narrower conidia (L / W ratio: 3.1 vs. 2.6) and differs from C. juglandicola and C. peakense by having wider conidia (L / W ratio: 3.1 vs. 3.3).

Figures

Figure 3. Phylogram of Colletotrichum boninense complex species based on Maximum Likelihood (ML) analysis of the dataset of combined ITS, gapdh, act, tub 2, chs 1 and his 3 genes. ML bootstrap support values above 60 % and Bayesian posterior probability above 0.90 are shown near nodes. Ex-type cultures are in bold. Isolates obtained in this study are highlighted with blue colors.

Figure 7. Colletotrichum juglandium (ex-holotype culture CFCC 59974) A symptoms caused by Colletotrichum juglandium B colonies on OA media above and below after 5 days at 25 ° C C conidiomata D, E conidiophores and conidia F, G conidia. Scale bars: 200 µm (C); 10 µm (D – G).