Marco A. S. Gama and
Rosa L. R. Mariano, Phytobacteriology Laboratory, Department of Agronomy, Universidade Federal Rural de Pernambuco, Av. Dom Manoel de Medeiros, s/n, Dois Irmãos, CEP 52171-900, Recife-PE, Brasil;
Francisco M. P. Viana, Laboratory of Plant Pathology, National Center for Tropical Agroindustrial Research, Empresa Brasileira de Pesquisa Agropecuária, Rua Dra. Sara Mesquita, 2270, Planalto PICI, CEP 60511-110, Fortaleza-CE, Brasil;
Marisa A. S. V. Ferreira, Institute of Biological Sciences, Department of Plant Pathology, Universidade de Brasília, Campus Universitário - Asa Norte, CEP 70910-900, Brasília-DF, Brasil; and
Elineide B. Souza, Department of Microbiology, Universidade Federal Rural de Pernambuco, Av. Dom Manoel de Medeiros, s/n, Dois Irmãos, CEP 52171-900, Recife-PE, Brasil
Go to article:
Accepted for publication 5 March 2011.
The export of cashew (Anacardium occidentale) nuts generates millions of dollars for the Brazilian economy annually. However, production may be limited by the occurrence of diseases that affect cashew trees, such as Xanthomonas spot and angular leaf spot, which are caused by pigmented strains of Xanthomonas and Xanthomonas citri pv. anacardii, respectively. Thirty-one pigmented strains of Xanthomonas were characterized for phenotypic, pathogenic, and molecular attributes. These strains were similar to X. citri pv. anacardii in phenotypical characteristics, sensitivity to antibiotics and copper compounds used in agriculture, epidemiology, and repetitive sequence-based polymerase chain reaction (rep-PCR) profiles. When inoculated into Brazilian pepper, cashew, mango, and hog plum seedlings, the pigmented strains of Xanthomonas and X. citri pv. anacardii produced similar symptoms. However, the pigmented strains of Xanthomonas were more aggressive toward cashew plants than toward the other hosts tested, which confirms their specificity. We conclude that pigmented strains of Xanthomonas are very aggressive on cashew trees and should not be considered casual pathogens of these hosts. Moreover, based on our results from rep-PCR and IS1595-PCR amplification, we suggest that these strains constitute a variant of X. citri pv. anacardii.
© 2011 The American Phytopathological Society