Analise da expressão diferencial de genes de citros em resposta a infecção por Xanthomonas axonopodis pv. citri / Differential gene expression of citrus in response to infection by Xanthomonas axonopodis pv. citri

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The citrus canker disease, caused by Xanthomonas axonopodis pv. citri (Xac), has emerged as one of the major threats to the Brazilian citriculture because it affects all commercial citrus varieties, decreases the production and quality of the fruits and can spread rapidly in the citrus growing areas. The symptoms include canker lesions, leading to abscission of fruits and leaves and general tree decline. Within the genus Xanthomonas, several genes have been found associated with pathogenicity and virulence. However, little is known about the mechanisms involved in the Xac- citrus interaction and the development of the canker disease. In this work we analyzed the differential expression of genes involved in the development of the canker disease in sweet orange (Citrus sinensis) leaves in response to Xac infection. Therefore we constructed two Supression Subtracted Hybridization (SSH) libraries with mRNA from leaves infiltrated with Xac or water after 10 days of inoculation. The libraries were screnned by dot blot and the 17 differentially expressed genes were sequenced and identified through BLAST searches against the Citrus EST and protein databases. The differential gene expression was evaluated by Northem blot and Real Time PCR (qPCR). To complement our analysis, the expression of 17 genes was compared in cDNA samples from citrus leaves that had been infilt:r:ated with Xac, water or X axonopodis pv. aurantifolii (Xaa), wich is not pathogenic to orange but causes canker in key lime. Our results show that Xac and Xaa induce and repress a similar set of genes, however at different leveis. We found that both pathogens altered the pathways of auxin transport and signaling, vesicle trafficking and transport, cell cycle and protein synthesis, photorespiration and disease response. Further analysis of these genes will be of great importance to understand the events triggering the development of the canker symptoms

ASSUNTO(S)

laranja cancro citrico xanthomonas axonopodis pv. citri oranges citrus canker supression subtracted hybridization (ssh) expressão genica diferencial differential gene expression biblioteca subtrativa suprimida (ssh)

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