Titre:	Phytophthora theobromicola sp. nov. : a new species causing black pod disease on cacao in Brazil
Auteur(s):	Decloquement, Jennifer Nathalie Yolande Ramos Sobrinho, Roberto Elias, Samuel Galvão Britto, Dahyana Santos Puig, Alina Sandra Reis, Ailton Silva, Rildo Alexandre Fernandes da Júnior, Jaime Honorato Luz, Edna Dora Martins Newman Pinho, Danilo Batista Marelli, Jean Philippe
metadata.dc.contributor.email:	danilopinho@unb.br jean-philippe.marelli@effem.com
metadata.dc.contributor.affiliation:	Universidade de Brasília, Departamento de Fitopatologia Biophyto Plant Health Universidade de Brasília, Departamento de Fitopatologia Mars Center for Cocoa Science U.S. Department of Agriculture, Agricultural Research Service, Subtropical Horticultural Research Station Embrapa, Centro Nacional de Pesquisa de Hortaliças Universidade de Brasília, Departamento de Fitopatologia Universidade Federal do Oeste da Bahia, Centro Multidisciplinar do Campus de Barra Centro de Pesquisas do Cacau, Comissão Executiva do Plano da Lavoura Cacaueira Universidade de Brasília, Departamento de Fitopatologia Mars Plant Sciences Laboratory
Assunto::	Diversidade biológica Cacaueiro - doenças e pragas Controle de pragas Phytophthora
Date de publication:	15-mar-2021
Editeur:	Frontiers Media
Référence bibliographique:	DECLOQUEMENT, Jennifer Nathalie Yolande et al. Phytophthora theobromicola sp. nov.: a new species causing black pod disease on cacao in Brazil. Frontiers in Microbiology, v. 12, 2021. DOI: https://doi.org/10.3389/fmicb.2021.537399. Disponível em: https://www.frontiersin.org/articles/10.3389/fmicb.2021.537399/full. Acesso em: 05 out. 2023.
Abstract:	Black pod disease, caused by Phytophthora species, is among the main limiting factors of cacao (Theobroma cacao L.) production. High incidence levels of black pod disease have been reported in Brazil, being induced by Phytophthora capsici, Phytophthora citrophthora, Phytophthora heveae, and Phytophthora palmivora. To assess the diversity of Phytophthora species affecting cacao in Brazil, 40 new isolates were obtained from cacao pods exhibiting symptoms of black pod disease collected in different smallholder farms in 2017. Further, ten cacao-infecting isolates morphologically identified as P. citrophthora and P. palmivora were molecularly characterized. The genomic regions beta-tubulin, elongation factor 1 alpha, heat shock protein 90, and internal transcribed spacer, and the mitochondrially encoded cytochrome c oxidase I and II genes were PCR-amplified and Sanger-sequenced from the cacao-infecting Phytophthora isolates. The morphological characterization and evaluation of the mycelial growth rates for the Phytophthora isolates were performed in vitro. Based on the molecular analysis and morphological comparisons, 19 isolates were identified as P. palmivora (clade 4). Interestingly, 31 isolates grouped together in the phylogenetic tree and were placed apart from previously known species in Phytophthora clade 2. Therefore, these isolates are considered as a new species herein referred to as Phytophthora theobromicola sp. nov., which produced papillate, semipapillate, and persistent sporangia on simple sporangiophores. The P. palmivora isolates were identified as A1 mating type by pairing each isolate with known A1 and A2 tester strains of P. capsici, but no oogonia/antheridia were observed when P. theobromicola was paired with the different tester strains. The P. theobromicola and P. citrophthora isolates showed higher mycelial growth rates, when compared to P. palmivora, on different media at 10, 15, and 20◦C, but similar values were observed when grown on clarified CA media at 25 and 30◦C. The pathogenicity tests carried out on pods of four cacao clones (CCN51, PS1319, Cepec2004, and CP49) showed significant variability among the isolates of both Phytophthora species, with P. theobromicola inducing higher rates of necrotic lesion expansion, when compared to P. palmivora. Here, two Phytophthora species were found associated with black pod disease in the state of Bahia, Brazil, and the previously undescribed P. theobromicola seems to be prevalent in field conditions. This is the first report of P. theobromicola on T. cacao. Also, these findings are crucial to improve the disease control strategies, and for the development of cacao materials genetically resistant to Phytophthora.
metadata.dc.description.unidade:	Instituto de Ciências Biológicas (IB) Departamento de Fitopatologia (IB FIT)
Licença::	Copyright © 2021 Decloquement, Ramos-Sobrinho, Elias, Britto, Puig, Reis, da Silva, Honorato-Júnior, Luz, Pinho and Marelli. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Fonte: https://www.frontiersin.org/articles/10.3389/fmicb.2021.537399/full. Acesso em: 05 out. 2023.
DOI:	https://doi.org/10.3389/fmicb.2021.537399
Collection(s) :	Artigos publicados em periódicos e afins

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