Title:	Xanthomonas euvesicatoria associated with outbreaks of bacterial blight of onion in Central Brazil.
Authors:	FERREIRA, L. da C. ALVES, A. R. MACEDO, W. da S. ROSSATO, M OLIVEIRA, V. R. QUEZADO-DUVAL, A. M.
Affiliation:	LUCIELLEN DA COSTA FERREIRA, UNIVERSIDADE DE BRASÍLIA; ANGELICA RODRIGUES ALVES, UNIVERSIDADE DE BRASÍLIA; WELLINGTON DA SILVA MACEDO; MAURÍCIO ROSSATO, UNIVERSIDADE DE BRASÍLIA; VALTER RODRIGUES OLIVEIRA, CNPH; ALICE MARIA QUEZADO DUVAL, CNPH.
Date Issued:	2026
Citation:	Plant Pathology, v. 75, n. 4, e70229, 2026.
Description:	Since 2018, outbreaks of typical bacterial blight caused by Xanthomonas have been observed in summer onion crops in central Brazil. To identify the Xanthomonas species involved and evaluate the role of rotation crops (e.g., soybean) and weeds, surveys were conducted at outbreak sites from 2018 to 2021. Forty-two xanthomonad-like isolates were obtained from symptomatic leaves (33 from onion, four from Euphorbia heterophylla, two from Amaranthus sp. and three from soybean). Isolates were analysed using PCR of the gumD gene and BOX-PCR, followed by multilocus sequence analysis (MLSA) of dnaK, fyuA, gyrB and rpoD genes. Representative isolates from MLSA clades and hosts were evaluated for pathogenicity on onion, E. heterophylla, Amaranthus retroflexus, soybean and common bean. Phylogenomic, type III secretion system (T3SS) effector and copper-insensitivity gene analyses were also performed. BOX-PCR revealed 11 haplotypes, some present within the same cultivar in different locations and year samples, as well as in coexisting weeds and crop species. Molecular analyses confirmed all isolates as Xanthomonas euvesicatoria, though not all onion isolates clustered with GenBank strains previously designated X. euvesicatoria pv. allii. The T3SS effector analysis identified a conserved core of 13 effectors, along with unique profiles such as XopR. No copper-insensitivity genes were detected. Onion isolates infected legumes and the weeds, whereas Amaranthus and soybean isolates did not infect onion. These findings emphasise the epidemiological relevance of managing weeds and soybean volunteers in onion fields, particularly during the summer season.
Thesagro:	Rotação de Cultura Erva Daninha Bactéria
Keywords:	Sequenciamento genômico Xanthomonas euvesicatoria
ISSN:	0032-0862
Type of Material:	Artigo de periódico
Access:	openAccess
Appears in Collections:	Artigo em periódico indexado (CNPH)