RESUMO
Agrobacterium tumefaciens causes crown gall disease. Although Agrobacterium can be popularly used for genetic engineering, the influence of aboveground insect infestation on Agrobacterium induced gall formation has not been investigated. Nicotiana benthamiana leaves were exposed to a sucking insect (whitefly) infestation and benzothiadiazole (BTH) for 7 d, and these exposed plants were inoculated with a tumorigenic Agrobacterium strain. We evaluated, both in planta and in vitro, how whitefly infestation affects crown gall disease. Whitefly-infested plants exhibited at least a two-fold reduction in gall formation on both stem and crown root. Silencing of isochorismate synthase 1 (ICS1), required for salicylic acid (SA) synthesis, compromised gall formation indicating an involvement of SA in whitefly-derived plant defence against Agrobacterium. Endogenous SA content was augmented in whitefly-infested plants upon Agrobacterium inoculation. In addition, SA concentration was three times higher in root exudates from whitefly-infested plants. As a consequence, Agrobacterium-mediated transformation of roots of whitefly-infested plants was clearly inhibited when compared to control plants. These results suggest that aboveground whitefly infestation elicits systemic defence responses throughout the plant. Our findings provide new insights into insect-mediated leaf-root intra-communication and a framework to understand interactions between three organisms: whitefly, N. benthamiana and Agrobacterium.
Assuntos
Agrobacterium tumefaciens/fisiologia , Hemípteros/fisiologia , Nicotiana/microbiologia , Nicotiana/parasitologia , Transformação Genética , Animais , Ciclopentanos/metabolismo , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Genes de Plantas , Modelos Biológicos , Dados de Sequência Molecular , Oxilipinas/metabolismo , Exsudatos de Plantas/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/microbiologia , Tumores de Planta/microbiologia , Tumores de Planta/parasitologia , Vírus de Plantas/fisiologia , Ácido Salicílico/metabolismo , Nicotiana/genéticaRESUMO
Shiga toxin-producing Escherichia coli causes bloody diarrhea and hemolytic-uremic syndrome and serious outbreaks worldwide. Here, we report the draft genome sequence of E. coli NCCP15657 isolated from a patient. The genome has virulence genes, many in the locus of enterocyte effacement (LEE) island, encoding a metalloprotease, the Shiga toxin, and constituents of type III secretion.