RESUMO
The epidemic situation of Moko disease-causing strains in Latin America and Brazil is unclear. Thirty-seven Ralstonia solanacearum strains from Brazil that cause the Moko disease on banana and heliconia plants were sampled and phylogenetically typed using the endoglucanase (egl) and DNA repair (mutS) genes according to the phylotype and sequevar classification. All of the strains belonged to phylotype II and a portion of the strains was typed as the Moko disease-related sequevars IIA-6 and IIA-24. Nevertheless, two unsuspected sequevars also harbored the Moko disease-causing strains IIA-41 and IIB-25, and a new sequevar was described and named IIA-53. All of the strains were pathogenic to banana and some of the strains of sequevars IIA-6, IIA-24, and IIA-41 were also pathogenic to tomato. The Moko disease-causing strains from sequevar IIB-25 were pathogenic to potato but not to tomato. These results highlight the high diversity of strains of Moko in Brazil, reinforce the efficiency of the egl gene to reveal relationships among these strains, and contribute to a better understanding of the diversity of paraphyletic Moko disease-causing strains of the R. solanacearum species complex, where the following seven distinct genetic clusters have been described: IIA-6, IIA-24, IIA-41, IIA-53, IIB-3, IIB-4, and IIB-25.
Assuntos
Variação Genética , Heliconiaceae/microbiologia , Musa/microbiologia , Doenças das Plantas/microbiologia , Ralstonia solanacearum/genética , Sequência de Bases , Brasil , DNA Bacteriano/química , DNA Bacteriano/genética , Dados de Sequência Molecular , Filogenia , Ralstonia solanacearum/patogenicidade , Análise de Sequência de DNARESUMO
A rust disease on the Brazilian orchid Pleurothallis mentigera was found in Mata do Jambreiro, a tropical forest in Minas Gerais State, caused by a fungus identified as Sphenospora kevorkianii Linder is described. P. mentigera Kraenzl. is added to S. kevorkianii host range.
