Predominance of Burkholderia cenocepacia lineages causing onion sour skin in the semi-arid region of north-east Brazil |
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Authors: | Ana D B Baia Adriano M F Silva Bárbara G Ribeiro Claudeana C Souza Wilson J Silva Júnior Valdir Q Balbino Carla M Leal Antônio R G de Farias Elineide B Souza Marco A S Gama |
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Institution: | 1. Departamento de Agronomia, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil;2. Departamento de Agronomia, Universidade Federal de Alagoas, Rio Largo, AL, Brazil;3. Departamento de Genética, Universidade Federal de Pernambuco, Recife, PE, Brazil;4. Crop Science Department, Georg-August-Universität Göttingen, Göttingen, LS, Germany;5. Departamento de Biologia, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil |
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Abstract: | Burkholderia cepacia was originally described as the causal agent of onion sour skin. However, this bacterium is now recognized as a complex of 22 closely related species, commonly referred to as the B. cepacia complex (BCC). Only a few taxonomic studies have been undertaken with the aim of understanding the diversity of species associated with onion sour skin. In this study, we used a polyphasic analysis including rep-PCR assay, biochemical and pathological profiles, and multilocus sequence analysis (MLSA) to characterize the BCC species associated with onion sour skin in the semi-arid region of north-east Brazil. Phylogenetic analysis of the recA of strains representing the genetic variability, as determined by rep-PCR, grouped the strains into four clades. Clades I and II represent B. cenocepacia lineages IIB and IIIA, respectively, while the strains in Clades III and IV clustered more closely to Clades I and II than to strains of any other BCC species. MLSA confirmed the existence of the four clades with a 1.00 posterior probability. A distance matrix indicated a low level of divergence among the strains of the four clades found in the MLSA, proving that B. cenocepacia lineages IIIA, IIIB, and a new lineage of B. cenocepacia are associated with onion sour skin in the semi-arid region of north-east Brazil. Also, surprisingly, no strain was identified as B. cepacia, indicating that this species probably does not play a role in this disease in this region. |
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Keywords: | Burkholderia cepacia complex multilocus sequence analysis onion crop polyphasic characterization |
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