Location: Mycology and Nematology Genetic Diversity and Biology Laboratory
Title: First report of Colletotrichum musicola causing anthracnose on Dioscorea alataAuthor
![]() |
AMARALL, ANA - Federal Rural University Of Pernambuco |
![]() |
DUARTE, INGRID - Federal Rural University Of Pernambuco |
![]() |
DA SILVA, ANTHONY - Federal Rural University Of Pernambuco |
![]() |
DA SILVA, FERNANDA - Federal Rural University Of Pernambuco |
![]() |
DOS SANTOS VIEIRA, WILLIE - University Of Brazil |
![]() |
MILLER, STEPHAN - Oak Ridge Institute For Science And Education (ORISE) |
![]() |
Castlebury, Lisa |
![]() |
CAMARA, MARCOS - Federal Rural University Of Pernambuco |
Submitted to: Journal of Plant Pathology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/9/2025 Publication Date: 1/25/2025 Citation: Amarall, A.G., Duarte, I.G., Da Silva, A.C., Da Silva, F.O., Dos Santos Vieira, W.A., Miller, S., Castlebury, L.A., Camara, M.P. 2025. First report of Colletotrichum musicola causing anthracnose on Dioscorea alata. Journal of Plant Pathology. https://doi.org/10.1007/s42161-025-01837-x. DOI: https://doi.org/10.1007/s42161-025-01837-x Interpretive Summary: Yams are an important food crop for millions of people worldwide. Unfortunately they often are infected with fungi that cause lesions on the leaves and reduced yields. Lesions were noted on yam leaves in Brazil and the fungus causing them was isolated. DNA sequences and microscopy were used to identify the fungus causing the disease. Four species causing this type of disease were previously known but this one did not match any of them. It was determined that a different fungal species was responsible for causing this disease. This information will be important to plant pathologists, regulatory officials and other scientists for management and tracking of this new disease problem on yams. Technical Abstract: Yam (Dioscorea alata) is an important crop in the Northeast region of Brazil. Colletotrichum alatae, C. siamense, C. fructicola, and C. karsti were the only species reported as causal agents of yam anthracnose previously. In July 2020, yam leaves with typical anthracnose symptoms were sampled from a field located in the municipality Vitória de Santo Antão (8°08'23.2"S 35°18'33.4"W), Pernambuco, Brazil. The leaves showed small, brown lesions that coalesced into irregular necrotic spots, dark in color and surrounded by a yellow halo. Anthracnose incidence was observed at 35% in 1ha of the area visited. Leaves with anthracnose symptoms were surface disinfected in 70% ethanol and 1.5% sodium hypochlorite, then rinsed with sterile distilled water, and plated onto potato dextrose agar (PDA) media. Plates were incubated at 25 'C for 5 days under continuous light. Pure cultures of fungal isolates were obtained by a single-spore isolation technique and one representative isolate (LM808) was deposited in the collection of Laboratório de Micologia at Universidade Federal Rural de Pernambuco, Recife, Pernambuco, Brazil. Fungal colonies developed greyish sepia smooth mycelium with vinaceous buff in the edge (Fig. 1). Conidia (n=30) were hyaline, aseptate, smooth-walled, cylindrical, both ends rounded 10.0–12.4 µm (av. 11.0 ± 0.4) and length/width ratio 2.2–3.0 (av. 2.5 ± 0.2) (Fig. 1). Partial sequences of the genes actin (ACT), ß-tubulin (TUB2), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the nuclear rDNA internal transcribed spacers (nrITS) were amplified, sequenced, and analyzed for LM808. Resulting sequences were deposited in GenBank (OQ789259, OQ884600, OQ789255, OQ745606, OQ831541). BLASTn searches showed 99%, 98%, 100%, 98% and 99% identities, respectively, with Colletotrichum musicola CBS 132885. Maximum likelihood multi-locus analysis placed isolate LM808 with strains of C. musicola with 100% bootstrap support and within the C. orchidearum species complex. Pathogenicity tests were carried out on 45-day-old yam plants in the greenhouse. Four fully developed leaves were wounded at two points with sterile needles. Ten microliters of conidial suspension (106 conidia mL-1) were deposited onto wounds. Pathogenicity was evaluated seven days after inoculation. Isolate LM808 produced necrotic lesions typical of anthracnose seven days post inoculation and were similar to the lesions observed on the original leaf specimens. The inoculated strain was re-isolated, and the identity was verified by molecular analysis. Control yam leaves were inoculated with 10 microliters of sterilized distilled water and kept under the same conditions. This is the first report of C. musicola causing anthracnose in yams worldwide. |