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First Report of Leaf Spot of Wild Rocket ( Diplotaxis tenuifolia ) Caused by Fusarium equiseti in Italy

2015; American Phytopathological Society; Volume: 99; Issue: 8 Linguagem: Inglês

10.1094/pdis-11-14-1169-pdn

1943-7692

A. Garibaldi, G. Gilardi, G. Ortu, M. L. Gullino,

Plant-Microbe Interactions and Immunity

HomePlant DiseaseVol. 99, No. 8First Report of Leaf Spot of Wild Rocket (Diplotaxis tenuifolia) Caused by Fusarium equiseti in Italy PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Leaf Spot of Wild Rocket (Diplotaxis tenuifolia) Caused by Fusarium equiseti in ItalyA. Garibaldi, G. Gilardi, G. Ortu, and M. L. GullinoA. Garibaldi, G. Gilardi, G. Ortu, and M. L. GullinoAffiliationsAuthors and Affiliations A. Garibaldi G. Gilardi G. Ortu M. L. Gullino , Centre of Competence for the Agro-Environmental Sector (AGROINNOVA) and DISAFA, Largo Braccini 2, 10095 Grugliasco, Italy. Published Online:26 Jun 2015https://doi.org/10.1094/PDIS-11-14-1169-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat During the spring of 2014, wild rocket (Diplotaxis tenuifolia) plants grown under greenhouse conditions in Campania (southern Italy) showed symptoms of a previously unreported foliar disease. Symptoms consisted of circular, gray-brown leaf spots 1 to 10 mm in diameter, each with a well-defined border, surrounded on the oldest leaves by a violet-brown halo. Approximately 10 to 15% of plants were affected, with an average 30 to 40% infected leaves/plant in a greenhouse of 2 ha of wild rocket produced at temperatures ranging from 20 to 28°C. Lesions were concentrated on the leaf margins of plants from the cotyledon stage through 20 to 25 days from sowing. An orange-brown colony with characteristics of Fusarium was isolated from leaf tissues of infected plants onto potato dextrose agar (PDA). Five isolates were subcultured on PDA and single-spore cultures were obtained. On carnation leaf agar (CLA), the isolates produced hyaline macroconidia with dorsiventral curvature, from 4- to 6-septate, and 20.2 to 36.8 × 2.9 to 4.5 um (average 28.8 × 3.8 µm). Macroconidia were produced in orange sporodochia from monophialides on branched conidiophores. Chlamydospores and microconidia were not observed. Such characteristics are typical of the genus Fusarium (Leslie and Summerell 2006). The internal transcribed spacer (ITS) region of ribosomal DNA from one representative isolate was amplified using the primers ITS1/ITS4 (White et al. 1990), and sequenced. BLASTn analysis of the 475-bp sequence showed 100% identity with ITS sequences of F. equiseti (GenBank Accessions Nos. KJ677236, KJ188664, and KJ562376). The nucleotide sequence was assigned GenBank Accession No. KM583445. To confirm pathogenicity of five isolates of this fungus, 30-day-old wild rocket plants were transplanted into 3-liter pots, each filled with a steamed peat substrate, and maintained in a greenhouse at 24 to 27°C. Five pots/treatment/isolate were used, each pot containing five plants. The inoculation was carried out by spraying leaves with a spore suspension of 1 × 105 CFU/ml (1 ml of inoculum per pot) prepared from a 10-day-old culture of the isolate on PDA. Five control pots were sprayed with distilled water. Plants were kept in a glasshouse and were covered with plastic bags for five days. The first symptoms, consisting of leaf spots each 1 mm in diameter surrounded by a violet-brown halo, developed 10 days after inoculation. The spots expanded in diameter for 30 days after inoculation. Noninoculated plants were asymptomatic. A fungal isolate showing the same morphological characteristics as F. equiseti was isolated consistently from symptomatic plants, while no fungi were isolated from the asymptomatic control plants, thus fulfilling Koch's postulates. The pathogenicity test was carried out twice. This is the first report of F. quiseti on D. tenuifolia in Italy as well as elsewhere. The pathogen has been observed previously in Italy on Eruca sativa (Garibaldi et al. 2011). The disease spread in 2014 on three commercial farms in southern as well as northern Italy, causing up to 20% yield losses.References:Garibaldi, A., et al. 2011. Plant Dis. 95:1315. https://doi.org/10.1094/PDIS-03-11-0220 Link, ISI, Google ScholarLeslie, J. F., and Summerell, B. A. 2006. The Fusarium Laboratory Manual. Blackwell, Ames, IA. Crossref, Google ScholarWhite, T. J. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Innis, M. A., et al., eds. Academic Press, San Diego. Crossref, Google ScholarDetailsFiguresLiterature CitedRelated Vol. 99, No. 8 August 2015SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 6 Aug 2015Published: 26 Jun 2015Accepted: 15 Mar 2015 Page: 1183 Information© 2015 The American Phytopathological SocietyCited byPseudomycosis and mycosis of rocket plant (arugula)Biljni lekar, Vol. 49, No. 1Unraveling the Fungal Community Associated with Leaf Spot on Crataegus sp.24 March 2020 | Microorganisms, Vol. 8, No. 3Emerging foliar and soil-borne pathogens of leafy vegetable crops: a possible threat to Europe19 February 2018 | EPPO Bulletin, Vol. 48, No. 1Crop Systems, Quality and Protection of Diplotaxis tenuifolia5 April 2018 | Agriculture, Vol. 8, No. 4Effect of a climate change scenario on Fusarium equiseti leaf spot on wild rocket and radish under phytotron simulation16 May 2017 | Phytoparasitica, Vol. 45, No. 3Fusarium Species and Their Associated Mycotoxins7 December 2016Temperature and leaf wetness affect the severity of leaf spot on lettuce and wild rocket incited by Fusarium equiseti17 December 2016 | Phytoparasitica, Vol. 44, No. 5