Plant Pathology (2021) 70, 521-533

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 and Marco A.S. Gama (2021)
Predominance of Burkholderia cenocepacia lineages causing onion sour skin in the semi-arid region of north-east Brazil
Plant Pathology 70 (3), 521-533
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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Link to article at publishers website

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Burkholderia cenocepacia	Onion/garlic/leek (Allium)	Brazil (NE)