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First Report of Gray Mold ( Botrytis cinerea ) on Sweet Basil ( Ocimum basilicum var. pilosum ) in northern Chile

2015; American Phytopathological Society; Volume: 100; Issue: 2 Linguagem: Inglês

10.1094/pdis-04-15-0390-pdn

1943-7692

Germán Sepúlveda, Wilson Huanca‐Mamani, Steffany Cárdenas, Mabel Arismendi, F. Salinas, E. E. Ferrada, B. A. Latorre,

Plant Pathogens and Resistance

HomePlant DiseaseVol. 100, No. 2First Report of Gray Mold (Botrytis cinerea) on Sweet Basil (Ocimum basilicum var. pilosum) in northern Chile PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Gray Mold (Botrytis cinerea) on Sweet Basil (Ocimum basilicum var. pilosum) in northern ChileG. Sepúlveda-Chavera, W. Huanca-Mamani, S. Cárdenas, M. Arismendi, F. Salinas, E. E. Ferrada, and B. A. LatorreG. Sepúlveda-ChaveraSearch for more papers by this author, W. Huanca-MamaniSearch for more papers by this author, S. CárdenasSearch for more papers by this author, M. ArismendiSearch for more papers by this author, F. SalinasSearch for more papers by this author, E. E. FerradaSearch for more papers by this author, and B. A. LatorreSearch for more papers by this authorAffiliationsAuthors and Affiliations G. Sepúlveda-Chavera W. Huanca-Mamani S. Cárdenas M. Arismendi F. Salinas , Universidad de Tarapacá, Arica, Chile E. E. Ferrada B. A. Latorre , Pontificia Universidad Católica de Chile, Santiago, Chile. Published Online:7 Jan 2016https://doi.org/10.1094/PDIS-04-15-0390-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Sweet basil (Ocimum basilicum Linn. var. pilosum (Willd.) Benth.) is a popular aromatic herb in the Lamiaceae. In July 2014, a disease was observed in commercial fields and greenhouse crops of sweet basil on about 10 ha in Azapa Valley (18°32′ S, 70°20′ W), Arica, Chile. Disease incidence ranged from 5 to 45% among fields and greenhouses. The pathogen infected stems, leaves, and inflorescences. Brown, necrotic lesions, each 0.5 to 2.0 cm in diameter, formed on the infected tissues. Lesions expanded rapidly under the humid and poor-aeration conditions of these fields and greenhouses, leading to total collapse of infected plants. On stems, leaves, and blossoms, the pathogen produced profuse conidia and mycelia, resulting in a moldy gray appearance. Botrytis cinerea Pers.:Fr. (Coley-Smith et al. 1980) was isolated consistently by incubating small pieces of infected leaves and stems sampled from the margin between diseased and healthy tissues, surface-disinfecting the pieces with 2% sodium hypochlorite for 5 min, and rinsing the pieces with sterilized water three times before plating onto potato dextrose agar (PDA) at 20°C for 4 to 5 days in the dark. Colonies were white to gray with fluffy aerial mycelia. Conidia (n = 100) produced on naturally infected stems were mostly ovoid, hyaline to lightly colored, smooth, 6.2 to 8.8 μm × 9.6 to 12.8 μm (average 7.5 × 10.6 μm), and born at the apex of erect, branched conidiophores. Sclerotia were absent on the host and in vitro. Pathogenicity tests were conducted separately with each of five isolates of B. cinerea by spraying a conidial suspension (4 × 105 conidia/ml), obtained from 7-day-old cultures on PDA, onto potted, 2-month-old sweet basil plants (n = 15). Inoculated plants were enclosed in polyethylene bags for 7 days at 18/25°C (night/day) with a 12-h photoperiod/day in a greenhouse. An equal number of noninoculated plants exposed to the same conditions were used as a control treatment. Symptoms appeared 2 to 7 days after inoculation on the leaves of all inoculated plants. B. cinerea was reisolated successfully onto PDA from inoculated plants, as described above, fulfilling Koch’s postulates. Noninoculated plants remained asymptomatic, and reisolations did not result in B. cinerea in culture. To confirm the identity of the pathogen as B. cinerea, genomic DNA was extracted from one isolate, and the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) and DNA-dependent RNA polymerase subunit II gene were amplified by PCR assay with universal primers ITS4/ITS5 (White et al. 1990) and RPB2for/RPB2rev primers (Staats et al. 2005), respectively. Sequences of DNA amplified (540 and 1,093 bp, respectively) were deposited in GenBank (Accession Nos. KP025968 and KR052881, respectively), and showed 99 to 100% identity with the corresponding sequences of Botryotinia fuckeliana accessions HQ171053 and AJ745674, respectively. B. cinerea has been reported in other areas of Chile (Acuña 2008), but this is the first report of gray mold in Azapa Valley in northern Chile. This disease could have a significant impact on the establishment and productivity of this important herb crop in open fields and greenhouses, especially under temperate, wet growing conditions.References:Acuña, R. 2008. Compendio de Fitopatógenos de Cultivos Agrícolas. Servico Agrícola y Ganadero. Gobierno de Chile, Santiago, Chile. Google ScholarColey-Smith, J. R., et al. 1980. The Biology of Botrytis. Academic Press, New York. Google ScholarStaats, M., et al. 2005. Mol. Biol. Evol. 22:333. ,https://doi.org/10.1093/molbev/msi020 Crossref, ISI, Google ScholarWhite, T. J., et al. 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. 100, No. 2 February 2016SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 15 Feb 2016Published: 7 Jan 2016First Look: 27 Jul 2015Accepted: 20 Jul 2015 Pages: 520-520 Information© 2016 The American Phytopathological Society