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First Report of Verticillium dahliae Causing Wilt on Annual Wormwood in Switzerland

2015; American Phytopathological Society; Volume: 100; Issue: 6 Linguagem: Inglês

10.1094/pdis-09-15-0971-pdn

1943-7692

Vincent Michel, Mireille Dessimoz, X. Simonnet,

Forest Insect Ecology and Management

HomePlant DiseaseVol. 100, No. 6First Report of Verticillium dahliae Causing Wilt on Annual Wormwood in Switzerland PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Verticillium dahliae Causing Wilt on Annual Wormwood in SwitzerlandV. V. Michel, M. Dessimoz, and X. SimonnetV. V. MichelSearch for more papers by this author, M. DessimozSearch for more papers by this author, and X. SimonnetSearch for more papers by this authorAffiliationsAuthors and Affiliations V. V. Michel M. Dessimoz , Agroscope, Institute for Plant Production Sciences, Research Center Conthey, CH-1964 Conthey, Switzerland X. Simonnet , Médiplant, CH-1964 Conthey, Switzerland. Published Online:7 Mar 2016https://doi.org/10.1094/PDIS-09-15-0971-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Annual wormwood (Artemisia annua L.) is highly valued for artemisinin, which has a strong effect against Plasmodium falciparum, the causal agent of malaria. Since 2010, the World Health Organization (WHO) recommends the use of drugs derived from A. annua to control the disease (WHO 2010). In 2011, four A. annua cultivars were tested in a field trial at Conthey (Switzerland). At the end of August 2011, the leaves of one of the cultivars showed wilt symptoms. Vascular discoloration was observed in the lower stem section of symptomatic plants. From aseptically removed stem tissue, the fungal strain Aa#2 was isolated on potato dextrose agar containing chlortetracycline. White mycelium and dark, pigmented microsclerotia formed after 10 to 14 days of incubation at 24°C. The conidiophores, conidiospores, and microslerotia of the fungus were of the size and shapes previously characterized for Verticillium dahliae (Hawksworth and Talboys 1970). The ribosomal intergenic spacer (rIGS) region of DNA of strain Aa#2 was amplified using the universal primers for fungi, LR12R and CNS25. The 376-bp amplified segment was sequenced using primers 318f and 1206r. A BLAST search of this segment (GenBank Accession No. KF772231) revealed 100% nucleotide identity to a rIGS sequence of V. dahliae. In 2012, the pathogenicity of V. dahliae on annual wormwood was confirmed in a trial at Agroscope, Conthey, Switzerland. At the end of August 2012, seedlings of the same proprietary cultivar on which symptoms were observed originally were grown in a greenhouse. In September, two strains of V. dahliae, Aa#2 and VdM (Accession No. of the latter, KF772232, isolated from Acer palmatum Thunb.) were each multiplied by adding colonized agar from the edges of each colony to 250-ml Erlenmeyer flasks containing 50 ml of expanded clay granules and 30 ml of autoclaved clarified V8 juice. The flasks were incubated in the dark at 24°C for seven weeks. Greenhouse soil (pH 7.4, 1:1 soil:water w:v) was autoclaved twice on consecutive days. Autoclaved soil was mixed with inoculated clay granules at 5% v:v. Plastic pots, each 0.5 liter, were filled with 400 ml of the mixture before a 10-week-old, 20- to 30-cm tall A. annua seedling was transplanted into each pot. Separate inoculum was prepared for each V. dahliae strain, and sterilized clay granules were used for the control pots. Three pots per treatment were prepared and then placed in a greenhouse set at 18 and 22°C by night and day, respectively. Inoculated and control pots were placed on separate trays to avoid cross-contamination from drainage water. A month later, the lower leaves of the plants inoculated with either strain became chlorotic with necrotic leaf tips. Ten days later, leaves of these plants exhibited wilting, vascular tissue of the basal stem turned brown, and V. dahliae was isolated onto PDA containing chlortetracycline for all these plants. Control plants showed no such symptoms and V. dahliae was not isolated from the stems. This is the first report of V. dahliae as a wilt pathogen of A. annua (Farr and Rossman 2015).References:Farr, D. F., and Rossman, A. Y. Fungal Databases, Syst. Mycol. Microbiol. Lab., ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/, 23 October 2015. Google ScholarHawksworth, D. L., and Talboys, P. W. 1970. Verticillium dahliae. Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK. Google ScholarWHO. 2010. Guidelines for the Treatment of Malaria, 2nd Ed. World Health Organization, Geneva, Switzerland. Google ScholarDetailsFiguresLiterature CitedRelated Vol. 100, No. 6 June 2016SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 12 May 2016Published: 7 Mar 2016First Look: 15 Dec 2015Accepted: 4 Dec 2015 Pages: 1235-1235 Information© 2016 The American Phytopathological SocietyCited byVerticillium dahliae (verticillium wilt)CABI Compendium, Vol. CABI CompendiumEfficacy of Different Forms of Green Manure Crops to Reduce Verticillium dahliae in Different Soils15 November 2021 | Global Journal of Agricultural Innovation, Research & Development, Vol. 8