First Report of Leaf Anthracnose Caused by Colletotrichum alatae on Water Yam (Dioscorea alata) in China

HomePlant DiseaseVol. 102, No. 1First Report of Leaf Anthracnose Caused by Colletotrichum alatae on Water Yam (Dioscorea alata) in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Leaf Anthracnose Caused by Colletotrichum alatae on Water Yam (Dioscorea alata) in ChinaC.-H. Lin, W.-Q. Wu, X.-M. Liao, W.-B. Liu, W.-G. Miao, and F.-C. ZhengC.-H. Lin†Corresponding author: C.-H. Lin; E-mail: E-mail Address: lin3286320@126.com, W.-Q. Wu, X.-M. Liao, W.-B. Liu, W.-G. Miao, and F.-C. ZhengAffiliationsAuthors and Affiliations C.-H. Lin † W.-Q. Wu X.-M. Liao W.-B. Liu W.-G. Miao F.-C. Zheng , Institute of Tropical Agriculture and Forestry of Hainan University/Key Laboratory of Protection and Development Utilization of Tropical Crop Germplasm Resources, Ministry of Education, Haikou, Hainan 572208, China. Published Online:9 Nov 2017https://doi.org/10.1094/PDIS-07-17-0979-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Water yam (Dioscorea alata [Dioscoreaceae]) is a vegetatively propagated tuberous food crop cultivated widely in the tropics and subtropics (Mignouna et al. 2003). It is the most widely distributed species of yam in China and eaten mainly as a vegetable. During July 2016, anthracnose-like lesions were observed on the leaves of cultivar Da56 at a plantation in Danzhou City, Hainan Province. Leaf symptoms began as small, brown, pinpoint spots <1 mm in diameter and enlarged to dark brown to almost black, irregular blotches >10 mm diameter with yellow haloes. Approximately 35% of the plants showed the same symptoms on their lower leaves. Symptomatic leaves were collected randomly from different parts of the field. Tissue was removed from the margin of three lesions per leaf. It was then surface sterilized in 75% ethanol, air-dried, plated on potato dextrose agar (PDA) plates, and incubated at 28°C and a 12-h photoperiod. Colonies with similar characteristics were produced after 4 days. Four isolates (DA1605-1608) from different leaves were subcultured on PDA using the single-spore method. After 4 days, the slow-growing colonies produced numerous, discrete colonies. The colonies contained dark-based acervuli with bright orange conidial spore masses and irregular sectors of pale gray pigment when viewed from below. Conidia were hyaline, aseptate, straight, and cylindrical with both ends rounded. They measured 12.7 to 21.7 × 5.4 to 8.9 µm (average 18.0 × 7.0 µm, n = 100). Appressoria were simple, elliptic to fusoid in shape. Perithecia were not seen. Morphological characteristics of the isolates matched descriptions of the slow-growing gray group of Colletotrichum alatae (Abang et al. 2002). To confirm the morphological identification, internal transcribed spacer region (ITS), chitin synthase (CHS-1), actin (ACT), and glyceraldehydes-3-phosphate dehydrogenase gene regions were amplified using universal primers ITS1/ITS4, CHS-79F/CHS-354R, ACT-512F/ACT-783R, and GDF/GDR and were sequenced (Weir et al. 2012). All four gene sequences from the four isolates shared 100% identity. These four gene sequences of isolate DA1605 were deposited in GenBank (accession nos. KY689723, KY689725, KY689724, and KY689726). A multilocus phylogenetic analysis performed with the reference sequences (Weir et al. 2012) revealed that the isolate clustered within C. alatae. Isolate DA1605 was deposited in the Agriculture Culture Collection of China as ACCC39281. For the pathogenicity test, a conidial suspension (1 × 106 spores/ml) of each isolate was prepared by harvesting conidia from 5-day-old cultures growing on PDA. The suspension was sprayed onto 10 detached, unwounded, healthy young leaves. The same number of control leaves was treated with sterile water. All leaves were kept in plastic boxes under moist conditions at 28°C and a 12-h photoperiod. Seven days after inoculation, black spots were observed on all inoculated leaves. No symptoms were observed on the control leaves, and no fungus was isolated. The fungus was reisolated from inoculated leaves, fulfilling Koch's postulates. The pathogen has been previously reported only on yam (D. alata) from Nigeria, Barbardos, India, and Guadeloupe (Abang et al. 2002, 2003; Weir et al. 2012). To our knowledge, this is the first record for C. alatae in China.References:Abang, M. M., et al. 2002. Plant Pathol. 51:63. https://doi.org/10.1046/j.0032-0862.2001.00655.x Crossref, ISI, Google ScholarAbang, M. M., et al. 2003. Afr. J. Biotechnol. 2:486. https://doi.org/10.5897/AJB2003.000-1098 Crossref, Google ScholarMignouna, H. D., et al. 2003. Afr. J. Biotechnol. 2:478. https://doi.org/10.5897/AJB2003.000-1097 Crossref, Google ScholarWeir, B. S., et al. 2012. Stud. Mycol. 73:115. https://doi.org/10.3114/sim0011 Crossref, ISI, Google ScholarThis study was supported by China Agriculture Research System (no. CARS-34-BC1) and the National Natural Science Foundation of China (no. 31560495).DetailsFiguresLiterature CitedRelated Vol. 102, No. 1 January 2018SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 20 Dec 2017Published: 9 Nov 2017First Look: 12 Sep 2017Accepted: 9 Sep 2017 Page: 248 Information© 2018 The American Phytopathological SocietyCited byCharacterization of some fungal pathogens causing anthracnose disease on yam in Cross River State, Nigeria29 June 2022 | PLOS ONE, Vol. 17, No. 6Strategies to combat the problem of yam anthracnose disease: Status and prospects17 July 2021 | Molecular Plant Pathology, Vol. 22, No. 10Colletotrichum species and complexes: geographic distribution, host range and conservation status29 September 2021 | Fungal Diversity, Vol. 110, No. 1