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.

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The survival of Ralstonia solanacearum A1-9 Rif race 1 phylotype I was studied in ten different soil types in the absence of the host plant as well as in infected tissues of the stem and root of bell peppers buried in the soil at 0, 5, and 15 cm. The survival time of R. solanacearum A1-9 Rif in the ten soil types ranged from 42 up to 77 days. Among the chemical and physical characteristics of the soil, clay content, residual moisture, and available water were positively correlated, and pH was negatively correlated, with survival time, population size at 42 days, and area under the population curve. The pathogen survival differed significantly in relation to the plant tissues, but not with respect to the incorporation depth of the infected tissues. The root tissue of bell pepper supported a larger bacterial population at 7 and 21 days (5 × 10 4 and 3.

Plant pathogenic Xanthomonas species attack a wide range of agriculture crops and is capable of surviving on weeds. In this study, Xanthomonas strains obtained from weeds grown withing vegetable crop fields in the state of Pernambuco, Northeast Brazil, were identified. Bacterial colonies resembling Xanthomonas were obtained from Aeollanthus suaveolens (strain CCRMXe03), Amaranthus lividus (CCRMXe01 and CCRMXe02), Sida glomerata (CCRMXe04), and Emilia fosbergii (CCRMXe04). All weeds but E. fosbergii exhibited lesions on the leaves. Phylogenetic analysis of the gyrB and rpoD genes and PCR-specific assays allowed to identify X. euvesicatoria pv. euvesicatoria (CCRMXe01, CCRMXe02, CCRMXe03, and CCRMXe04) and X. campestris pv. campestris (CCRMXcc371). All strains but CCRMXe03 were pathogenic to its host of origin. All X. euvesicatoria pv. euvesicatoria strains were pathogenic to leaves and fruits of tomato and bell pepper. Two strains, CCRMXe03 and CCRMXe04, were capable of inducing soft rot in fruits. Amylolytic activity was found in all strains and two strains (CCRMXe03 and CCRMXe04) degraded pectate. Strain CCRMXcc371 was pathogenic to cabbage, kale, cauliflower, and broccoli. This work provides new knowledge of hosts for two important plant pathogenic bacteria for vegetable crops.