Phylogeny and variability of Colletotrichum truncatum associated with soybean anthracnose in Brazil.

Autor: Rogério F; Departamento de Fitopatologia e Nematologia (ESALQ/USP), Universidade de São Paulo, Piracicaba, São Paulo, Brazil., Ciampi-Guillardi M; Departamento de Fitopatologia e Nematologia (ESALQ/USP), Universidade de São Paulo, Piracicaba, São Paulo, Brazil., Barbieri MC; Departamento de Fitopatologia e Nematologia (ESALQ/USP), Universidade de São Paulo, Piracicaba, São Paulo, Brazil., Bragança CA; Universidade Federal do Recôncavo da Bahia (UFRB), Cruz das Almas, Bahia, Brazil., Seixas CD; Embrapa Soja, Londrina, Paraná, Brazil., Almeida AM; Embrapa Soja, Londrina, Paraná, Brazil., Massola NS Jr; Departamento de Fitopatologia e Nematologia (ESALQ/USP), Universidade de São Paulo, Piracicaba, São Paulo, Brazil.
Jazyk: angličtina
Zdroj: Journal of applied microbiology [J Appl Microbiol] 2017 Feb; Vol. 122 (2), pp. 402-415.
DOI: 10.1111/jam.13346
Abstrakt: Aims: Fungal diseases are among the main factors limiting high yields of soybean crop. Colletotrichum isolates from soybean plants with anthracnose symptoms were studied from different regions and time periods in Brazil using molecular, morphological and pathogenic analyses.
Methods and Results: Bayesian phylogenetic inference of GAPDH, HIS3 and ITS-5.8S rDNA sequences, the morphologies of colony and conidia, and inoculation tests on seeds and seedlings were performed. All isolates clustered only with Colletotrichum truncatum species in three well-separated clusters. Intraspecific genetic diversity revealed 27 distinct haplotypes in 51 fungal isolates; some of which were identical to C. truncatum sequences from other regions around the world, while others were related to alternative hosts. Conidia were falcate, hyaline, unicellular and aseptate, formed in acervuli, with variable dimensions. Despite being pathogenic to seedlings by both inoculation methods, variation was observed in the aggressiveness of the tested isolates, which was not correlated with genetic variation.
Conclusion: The identification of C. truncatum in the sampled isolates was evidenced as being the only causal agent of soybean anthracnose in Brazil until 2007, with relevant genetic, morphological and pathogenic variability as well as a broad geographical origin. The wide distribution of the predominant C. truncatum haplotype indicated the existence of a highly efficient mechanism of pathogen dispersal over long distances, reinforcing the role of seeds as the primary source of disease inoculum.
Significance and Impact of the Study: The characterization and distribution of Colletotrichum species in soybean-producing regions in Brazil is fundamental for understanding the disease epidemiology and for ensuring effective control strategies against anthracnose.
(© 2016 The Society for Applied Microbiology.)
Databáze: MEDLINE
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