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First Report of Black Rot on Apple Fruit Caused by Diplodia seriata in California

2017; American Phytopathological Society; Volume: 102; Issue: 4 Linguagem: Inglês

10.1094/pdis-07-17-1023-pdn

1943-7692

Mario Crespo Miguel, Juan Moral, Themis J. Michailides, Florent P. Trouillas,

Plant Pathogenic Bacteria Studies

HomePlant DiseaseVol. 102, No. 4First Report of Black Rot on Apple Fruit Caused by Diplodia seriata in California PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Black Rot on Apple Fruit Caused by Diplodia seriata in CaliforniaM. Crespo, J. Moral, T. J. Michailides, and F. P. TrouillasM. Crespo†Corresponding author: M. Crespo; E-mail: E-mail Address: [email protected]Search for more papers by this author, J. MoralSearch for more papers by this author, T. J. MichailidesSearch for more papers by this author, and F. P. TrouillasSearch for more papers by this authorAffiliationsAuthors and Affiliations M. Crespo † J. Moral T. J. Michailides F. P. Trouillas , University of California-Davis, Department of Plant Pathology, Kearney Agricultural Research and Extension Center, Parlier, CA 93648. Published Online:12 Feb 2018https://doi.org/10.1094/PDIS-07-17-1023-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat A fruit rot was observed on apple (Malus domestica Borkh.) cv. Fuji in a commercial orchard during 2015 and 2016 in San Joaquin Valley County, California. Early symptoms of fruit rot included light to dark brown lesions (3 to 4 cm in diameter) with defined margins and firm texture. In more advanced stages of the disease, the fruit became completely rotten and soft. Additionally, the affected apple trees developed fungal fruiting bodies on shoots initially blighted by Erwinia amylovora, the causal agent of fire blight. A fungal species was consistently isolated by cutting small pieces of symptomatic fruit and blighted shoots and placing them on acidified potato dextrose agar (APDA). The plates were incubated at 22°C for 7 days. To obtain pure fungal cultures, hyphal tips were transferred to PDA. Upon isolation, 74.5% of the colonies formed on PDA developed dense white aerial mycelia that became dark gray after 7 days. The reverse of the colony ranged from olive green to black. The fungus formed pycnidia on pistachio leaf agar medium (Chen et al. 2014) after 15 days of incubation at room temperature (22 to 25°C). Conidia were initially hyaline, becoming dark brown at maturity, aseptate, ovoid, rounded at both ends, and 8 to 12 × 14 to 24 µm (n = 50). Based on cultural and morphological characteristics, the pathogen was identified as Diplodia seriata De Not (Sutton 2014). In addition, a second species was isolated from 10% of the blighted shoots but not from the rotted fruit. This second species was identified based on cultural and conidial characteristics as D. mutila (Fr.:Fr.). To confirm the identification of both species, the ITS and EF1-α loci were amplified with the primer sets ITS1/ITS4 (White et al. 1990) and EF1-728F/EF1-986R (Carbone and Kohn 1999), respectively. BLAST searches against GenBank showed ≥99% nucleotide identity with reference sequences of D. seriata (2K33) and D. mutila (CBS112553) for both DNA regions (accessions nos. KF778795 and KF778985; and AY259093 and AY573219, respectively). The ITS and EF sequences of one representative isolate of D. seriata (KARE1701) isolated from shoots, and another isolate of D. mutila (KARE1696) were deposited in GenBank (MF346337, MF346339, MF346338, MF346340 for ITS and EF1-α, respectively). The pathogenicity of one representative isolate of each fungal species was tested on apple fruit cv. Fuji. For that, 20 fruit were surface-disinfected with 75% ethanol solution for 30 s. Each fruit was wounded on opposite sides using a sterile 5 mm diameter cork borer and inoculated with 5 mm diameter mycelial plugs from 7-day-old cultures. To serve as negative control, 10 apple fruits were inoculated with sterile PDA plugs. Fruits were incubated in humid chambers at 22°C for 10 days. Symptoms of black rot developed on all inoculated fruit with lesions ranging from 2.1 to 6.9 cm in diameter. No symptoms were observed on the negative control fruit. Koch’s postulates were fulfilled by reisolating each fungus from the inoculated fruit. Both D. seriata and D. mutila caused similar (Student’s t-test, P = 0.824) lesion diameter on the inoculated apple fruit. The experiment was repeated once. Although black rot is well known in the eastern United States, to our knowledge, this is the first report of black rot of apple caused by D. seriata in California.References:Carbone, I., and Kohn, L. M. 1999. Mycologia 91:553. https://doi.org/10.2307/3761358 Crossref, ISI, Google ScholarChen, S. F., et al. 2014. Fungal Divers. 67:157. https://doi.org/10.1007/s13225-014-0285-6 Crossref, ISI, Google ScholarSutton, T. B. 2014. Black rot. Page 23 in: Compendium of Apple and Pear Diseases and Pests. T. B. Sutton, et al., eds. American Phytopathological Society, St. Paul, MN. Google ScholarWhite, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis, et al., eds. Academic Press, San Diego. Crossref, Google ScholarDetailsFiguresLiterature CitedRelated Vol. 102, No. 4 April 2018SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 15 Mar 2018Published: 12 Feb 2018First Look: 22 Nov 2017Accepted: 17 Nov 2017 Page: 824 Information© 2018 The American Phytopathological SocietyCited byComparison of various deep convolutional neural network models to discriminate apple leaf diseases using transfer learning24 August 2022 | Journal of Plant Diseases and Protection, Vol. 129, No. 6Mycosynthesized Fe2O3 nanoparticles diminish brown rot of apple whilst maintaining composition and pertinent organoleptic properties1 May 2022 | Journal of Applied Microbiology, Vol. 132, No. 5Diplodia seriata (grapevine trunk disease)CABI Compendium, Vol. CABI CompendiumBotryosphaeria stevensii (Botryosphaeria disease, grapevine)CABI Compendium, Vol. CABI CompendiumLasiodiplodia mitidjana sp. nov. and other Botryosphaeriaceae species causing branch canker and dieback of Citrus sinensis in Algeria20 May 2020 | PLOS ONE, Vol. 15, No. 5A Richer Community of Botryosphaeriaceae Within a Less Diverse Community of Fungal Endophytes in Grapevines than in Adjacent Forest Trees Revealed by a Mixed Metabarcoding StrategyBenoit Laurent, Marylise Marchand, Emilie Chancerel, Gilles Saint-Jean, Xavier Capdevielle, Charlotte Poeydebat, Anthony Bellée, Gwenaëlle Comont, Laure Villate, and Marie-Laure Desprez-Loustau24 July 2020 | Phytobiomes Journal, Vol. 4, No. 3Full Issue PDF7 August 2020 | Phytobiomes Journal, Vol. 4, No. 3Identification and characterization of Diplodia mutila, D. seriata, Phacidiopycnis washingtonensis and Phacidium lacerum obtained from apple (Malus x domestica) fruit rot in Maule Region, Chile24 November 2018 | European Journal of Plant Pathology, Vol. 153, No. 4First Report of Black Rot Caused by Diplodia seriata on AppleResearch in Plant Disease, Vol. 24, No. 4