Identificação de uma ferredoxina que interage com a proteína Sw-5 que confere resistência a tospovírus

• Autor(a) principal: Almeida, Leonardo Augusto de
• Data de Publicação: 2006
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4742
• topic: Resistência a tospovirus; Sistema duplo-híbrido de leveduras; Resistance to tospovirus; Yeasts two hybrid system; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL

The Sw-5 protein codified by the tomato Sw-5 gene confers broad spectrum tospovirus resistance. This protein contains a coil-coiled aminoterminal domain, a central nucleotide binding site domain and a leucine-rich repeat carboxi-terminal domain. These domains suggest that Sw-5 recognizes directly or indirectly virus elicitors and it participates in a signal transduction pathway that leads to the death of infected cells and activation of plant defense responses. The objective of this work was to identifiy and characterize genes encoding proteins that interacts physically with Sw-5 in the yeast two hybrid system. The screening of 5x107 Nicotiana benthamina cDNA clones, using the yeast mating strategy, did not yield any protein capable to interact with Sw-5. Analyzing 1,8 x 105 clones by co-transformation strategy, it was possible identify a cDNA that encodes an chloroplast ferredoxin I (Nb-Fd1) capable to interact with Sw-5. This protein contains a domain and a signature of 2Fe-2S proteins. Virus-induced silencing of the Nb-Fd1 gene leads to a grater number of local necrotic lesions and apical lesions in resistance plants challenged with tospovirus showing that this gene is important for tomato tospovirus resistance. This phenotype indicates that Nb-Fd1 is possibly involved in cellular redox state alteration, reactive oxygen species accumulation and programmed cell death activation processes mediated by Sw-5.