Produção Nacional
Revisado por pares
First Report of Cladode and Foot Rots Caused by Pythium aphanidermatum on Cactus ( Nopalea cochenillifera )
2016; American Phytopathological Society; Volume: 100; Issue: 8 Linguagem: Inglês
10.1094/pdis-12-15-1507-pdn
ISSN1943-7692
AutoresFrederico Monteiro Feijó, Roberto Ramos‐Sobrinho, M. J. S. Silva, L. F. Barbosa, Danilo Batista Pinho, Iraíldes Pereira Assunção, Gaus Silvestre de Andrade Lima,
Tópico(s)Plant Pathogens and Fungal Diseases
ResumoHomePlant DiseaseVol. 100, No. 8First Report of Cladode and Foot Rots Caused by Pythium aphanidermatum on Cactus (Nopalea cochenillifera) PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Cladode and Foot Rots Caused by Pythium aphanidermatum on Cactus (Nopalea cochenillifera)F. M. Feijó, R. Ramos-Sobrinho, M. J. S. Silva, L. F. Barbosa, D. B. Pinho, I. P. Assunção, and G. S. A. LimaF. M. FeijóSearch for more papers by this author, R. Ramos-SobrinhoSearch for more papers by this author, M. J. S. SilvaSearch for more papers by this author, L. F. BarbosaSearch for more papers by this author, D. B. PinhoSearch for more papers by this author, I. P. AssunçãoSearch for more papers by this author, and G. S. A. LimaSearch for more papers by this authorAffiliationsAuthors and Affiliations F. M. Feijó R. Ramos-Sobrinho M. J. S. Silva L. F. Barbosa , Setor de Fitossanidade/Centro de Ciências Agrárias, Universidade Federal de Alagoas, Rio Largo, AL, Brazil, 57100-000 D. B. Pinho , Departamento de Fitopatologia, Universidade de Brasília, Brazil, 70910-900 I. P. Assunção G. S. A. Lima , Setor de Fitossanidade/Centro de Ciências Agrárias, Universidade Federal de Alagoas, Rio Largo, AL, Brazil, 57100-000. Published Online:26 May 2016https://doi.org/10.1094/PDIS-12-15-1507-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Nopalea cochenillifera is a Cactaceae widely used for animal feeding during the dry season in the Brazilian semiarid. In the last years, Pythium-induced rot has caused the death of plants in this region. As several Pythium species are commonly associated with a single host (Kimati et al. 2005), this study aimed to determine the etiology of the disease on N. cochenillifera using morphological and molecular data. Diagnosis was performed on symptomatic plants collected in March 2015 (beginning of the rainy season) in a commercial field in Santana do Ipanema County, State of Alagoas, Brazil. Composted cattle manure was used as fertilizer in this N. cochenillifera-growing area. Pythium-induced brown rot on cladodes initially are water soaked, become elliptical and pale brown, and quickly enlarge in size causing tissue rot. Pythium sp. infects foot and cladode tissues near the soil surface, inducing cladode and foot rot symptoms, and consequently death of young plants. Two isolates were obtained on potato dextrose agar (PDA) at 25°C, and Pythium-derived cultures were deposited in the Coleção de Culturas de Fungos Fitopatogênicos da Universidade Federal de Alagoas (codes COUFAL1984 and COUFAL1985). Colonies on PDA were white and cottony; and in reverse uniformly white with a growth rate of 18 mm/day at 25°C. The pathogen has been recognized as Pythium aphanidermatum by its hyaline and nonseptate hyphae with filamentous-inflated sporangia; antheridia barrel-shaped; oogonia terminal on lateral hyphae, wall smooth, 23 to 25 µm in diameter, and oospores very loose in the oogonium, thick and smooth wall, 21 to 23 µm in diameter. To confirm identification, partial sequences of the internal transcribed spacer (ITS) and cytochrome c oxidase subunit 2 (Cox2) genomic regions were obtained and deposited in GenBank (Accession Nos. KU324667 to KU324670). The sequences of ITS and Cox2 showed 100% and 99% identity, respectively, with sequences from P. aphanidermatum culture-collection CBS:118.80. Additionally, our isolates clustered with others P. aphanidermatum in a Bayesian phylogenetic tree based on concatenate sequences (ITS and Cox2) (study 18660 deposited in TreeBASE). To confirm pathogenicity, PDA discs of 5 mm or mycelial suspension were taken from a 15-day-old culture (grown at 25°C) and deposited on three cactus cladodes superficially wounded with a sterilized needle. In control cladodes, only PDA discs without oomycete growth or sterilized distilled water were used. Cladodes were kept for 2 days in a humid chamber at 25°C. After 1 day, soaked and pale brown lesions were observed on 100% of the inoculated cladodes, which spread throughout the cladodes in 6 days after inoculation. No disease symptom was observed on the control cladodes. To fulfill Koch’s postulates, the oomycete P. aphanidermatum was successfully reisolated from inoculated cladodes. Although P. aphanidermatum to infect a wide host range (Laundon and Waterson 1964), this pathogen has been previously reported only on Echinocactus grusonii, Opuntia dillenii, O. ficus-indica, Schlumbergera truncate, and Zygocactus truncatus in Cactaceae (Farr and Rossman 2016). To our knowledge, this is the first report of P. aphanidermatum inducing foot and cladode rots on N. cochenillifera worldwide.References:Farr, D. F., and Rossman, A. Y. 2016. Fungal Databases, Syst. Mycol. and Microbiol. Lab. ARS, USDA. Online: http://nt.ars-grin.gov/fungaldatabases/ Google ScholarKimati, H., et al. 2005. Manual de Fitopatologia, Vol. 2. Editora Agronômica Ceres Ltda., São Paolo, Brazil. Google ScholarLaundon, G. F., and Waterson, J. M. 1964. CMI Descriptions Pathogenic Fungi Bacteria. 36:1. Google ScholarDetailsFiguresLiterature CitedRelated Vol. 100, No. 8 August 2016SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 22 Jul 2016Published: 26 May 2016First Look: 6 Apr 2016Accepted: 27 Mar 2016 Pages: 1797-1797 Information© 2016 The American Phytopathological SocietyCited byNopalea cochenillifera (cochineal cactus)CABI Compendium, Vol. CABI CompendiumPythium aphanidermatum (damping-off)CABI Compendium, Vol. CABI CompendiumBotryosphaeriaceae species associated with the pickly pear cactus, Nopalea cochenillifera5 August 2019 | Tropical Plant Pathology, Vol. 44, No. 5Identification of Colletotrichum species associated with brown spot of cactus prickly pear in Brazil15 March 2018 | Tropical Plant Pathology, Vol. 43, No. 3
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