Produção Nacional
Revisado por pares
Description of Golovinomyces orontii as the Causal Agent of Lettuce ( Lactuca sativa ) Powdery Mildew in Brazil
2018; American Phytopathological Society; Volume: 103; Issue: 4 Linguagem: Inglês
10.1094/pdis-09-18-1514-pdn
ISSN1943-7692
AutoresCléia Santos Cabral, Maria do Desterro Mendes dos Santos, R. C. F. Borges, M. E. N. Fonseca, L. S. Boiteux, Ailton Reis,
Tópico(s)Plant Pathogens and Resistance
ResumoHomePlant DiseaseVol. 103, No. 4Description of Golovinomyces orontii as the Causal Agent of Lettuce (Lactuca sativa) Powdery Mildew in Brazil PreviousNext DISEASE NOTES OPENOpen Access licenseDescription of Golovinomyces orontii as the Causal Agent of Lettuce (Lactuca sativa) Powdery Mildew in BrazilC. S. Cabral, M. D. M. Santos, R. C. F. Borges, M. E. N. Fonseca, L. S. Boiteux, and A. ReisC. S. CabralDepartamento de Fitopatologia, Universidade de Brasília, Brasília–DF, Brazil; and , M. D. M. SantosDepartamento de Fitopatologia, Universidade de Brasília, Brasília–DF, Brazil; and , R. C. F. BorgesDepartamento de Fitopatologia, Universidade de Brasília, Brasília–DF, Brazil; and , M. E. N. FonsecaCNPH/Embrapa Hortaliças, Brasília–DF, Brazil, L. S. Boiteux†Corresponding author: L. S. Boiteux; E-mail: E-mail Address: leonardo.boiteux@embrapa.brhttp://orcid.org/0000-0002-5791-8002CNPH/Embrapa Hortaliças, Brasília–DF, Brazil, and A. Reishttp://orcid.org/0000-0002-5705-3002CNPH/Embrapa Hortaliças, Brasília–DF, BrazilAffiliationsAuthors and Affiliations C. S. Cabral1 M. D. M. Santos1 R. C. F. Borges1 M. E. N. Fonseca2 L. S. Boiteux2 † A. Reis2 1Departamento de Fitopatologia, Universidade de Brasília, Brasília–DF, Brazil; and 2CNPH/Embrapa Hortaliças, Brasília–DF, Brazil Published Online:4 Feb 2019https://doi.org/10.1094/PDIS-09-18-1514-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Lettuce (Lactuca sativa L.) is the most important leafy vegetable crop in Brazil, being affected by a number of fungal diseases. Severe powdery mildew (PM) symptoms (100% incidence) were observed in commercial lettuce cultivar 'Caipira' plantings in Formosa, Goiás State (2015) and 'Milena' in Planaltina, Federal District (2018) under hydroponic conditions in Central Brazil. Typical whitish fungal colonies were observed on both leaf surfaces. PM infection induced leaf distortion, chlorosis, necrosis, and reduced plant growth. Morphological analyses of fungal isolates revealed straight and hyaline conidiophores (100.8 to 268.9 × 10.4 to 13.6 μm) with cylindrical foot cells ranging from 56.2 to 63.3 × 7.9 to 8.6 μm. Conidia (n = 30) were hyaline, ellipsoid to ovate (27.7 to 35.1 × 13 to 14 µm), and produced two to six conidia in sinuous chains. Chasmothecia were not observed. Pathogenicity assays were performed under greenhouse conditions by inoculating seedlings of cultivar Caipira via leaf-to-leaf contact with already-infected lettuce plants. Noninoculated plants served as controls. Only inoculated plants displayed conspicuous PM colonies 7 days after inoculation. The fungus from the inoculated plants was morphologically identical to that from the original isolates. The fungus was tentatively identified as Golovinomyces orontii (Braun and Cook 2012). To confirm this classification, the total genomic DNA of three lettuce-infecting isolates (named as Gollac1, Gollac2, and Gollac3) was extracted from conidial suspensions using a modified cetyltrimethylammonium bromide protocol (Boiteux et al. 1999). Purified DNA was used as a template in polymerase chain reaction assays with a pair of primer targeting the internal transcribed spacer (ITS) rDNA region: PM ITS1 (5′-TCGGACTGGCCYAGGGAGA-3′) and PM ITS2 (5′-TCACTCGCCGTTACTGAGGT-3′) (Cunnington et al. 2003). BLASTn alignments of the ITS sequences from the Brazilian lettuce isolates (KY984064 to KY984066) indicated 100% identity among themselves and also with G. orontii isolates reported infecting L. sativa and L. scariola in Japan (AB769447 and AB077688) and Cirsium arvense (L.) Scop. (Asteraceae) in Italy (KJ438822). A Bayesian inference analysis (Geneious R8) was carried out with several PM-inducing isolates from the GenBank. Arthrocladiella mougeotii (AF073358) was employed as outgroup. All lettuce-infecting isolates from Brazil clustered (0.98 posterior probability) with isolates of G. orontii 'group 3' (Takamatsu et al. 2013). G. orontii has been reported on a wide range of botanical families (Braun and Cook 2012). Infection of lettuce by G. orontii was already reported in European countries, North America, South Africa, Chile, Argentina, Australia, Israel, Japan, and Korea (Farr and Rossman 2018) and now in Brazil. Breeding for resistance is one of the few sustainable strategies for PM management in this crop.References:Boiteux, L. S., et al. 1999. J. Am. Soc. Hortic. Sci. 124:32. Crossref, ISI, Google ScholarBraun, U., and Cook, R. T. A. 2012. Taxonomic Manual of the Erysiphales (Powdery Mildews). CBS Biodiversity Series No. 11. CBS, Utrecht, the Netherlands. Google ScholarCunnington, J. H., et al. 2003. Australas. Plant Pathol. 32:421. https://doi.org/10.1071/AP03045 Crossref, ISI, Google ScholarFarr, D. F., and Rossman, A. Y. 2018. Fungal Databases, Syst. Mycol. Microbiol. Lab., ARS, USDA. https://nt.ars-grin.gov/fungaldatabases/. Google ScholarTakamatsu, S., et al. 2013. Mycologia 105:1135. https://doi.org/10.3852/13-046 Crossref, ISI, Google ScholarFunding: Funding was provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.DetailsFiguresLiterature CitedRelated Vol. 103, No. 4 April 2019SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionGray mold on kiwifruit leaves caused by Botrytis cinerea (courtesy Guoshu Gong and Qinjun Tao); sunflower rust on bracts (courtesy Sam Markell); cucumber plant with mosaic symptoms caused by papaya ringspot virus (courtesy Roger Jones). Metrics Article History Issue Date: 10 Apr 2019Published: 4 Feb 2019First Look: 9 Oct 2018Accepted: 4 Oct 2018 Pages: 761-761 Information© 2018 The American Phytopathological SocietyFundingConselho Nacional de Desenvolvimento Científico e TecnológicoCoordenação de Aperfeiçoamento de Pessoal de Nível SuperiorCited bySeed Priming with Silicon Improves Plant Resistance to Downy Mildew (Bremia lactucae) in Lettuce Seedlings by Intensifying Antioxidant Defense Systems24 June 2022 | Silicon, Vol. 14, No. 18An algal extract enriched with amino acids increases the content of leaf pigments but also the susceptibility to the powdery mildew of lettuce18 May 2022 | Phytoparasitica, Vol. 161Powdery Mildews on Lactuca Species – A Complex View of Host-Pathogen Interactions6 May 2020 | Critical Reviews in Plant Sciences, Vol. 39, No. 1
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