Caracterização funcional do fator de transcrição GmNAC6 de soja (Glycine max) e padrão de expressão de genes GmNACs em resposta a estímulos bióticos

• Autor(a) principal: Faria, Jerusa Araújo Quintão Arantes
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2415
• topic: GmNAC6; Soja; Estimúlos bióticos; GmNAC6; Soybean; Biotic stimulus; CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA::BIOLOGIA MOLECULAR

The plant-specific transcription factors belonging to the NAC family perform functions in development events and defense response. In addition to seven NAC genes previously described (GmNAC1-GmNAC6 and GmATAF), four new genes of the GmNAC family (Gm82, Gm119, Gm178 e Gm258) were analyzed in response to biotic stress. GmATAF, GmNAC3 e GmNAC4 were consistently induced by common factors of pathogenesis, such as wounding and pathogen infection (both compatible and incompatible interactions). GmNAC1 was transiently induced by wounding. Gm82 was induced during the hypersensitive response and systemic condition, whereas Gm119 displayed high levels of expression in compatible and incompatible interactions. In contrast, GmNAC2 and GmNAC5 were not up-regulated by biotic stimuli. Expression of GmNAC6 in tobacco leaves resulted in cell death, causing leaf yellowing and necrosis, chlorophyll loss, malondialdehyde production, and induction of the PRs defense genes. Consistent with the presence of defenserelated putative elements in the GmNAC6 promoter region, this transfactor was induced by wounding, compatible pathogen and systemic response. Overexpression of NRP-A and NRP-B, which are involved in cell death events, increased GmNAC6 transcripts. These results are consistent with the early response of NRPs in response to pathogen attack in comparison with the late response of GmNAC6. Nevertheless, transient expression of GmNAC6 downregulated NRP-A expression. All together, these results implicated GmNAC6 as a downstream component of the NRPs- mediated cell death signalling. Further experiments are necessary to elucidate the signaling pathway involved NRPs and GmNAC6.