Role of auxin and gibberellin in citrus canker development and in the transcriptional control of cell-wall remodeling genes modulated by Xanthomonas axonopodis pv. citri

Autor(es)

Cernadas, Raul Andres ^[1] ; Benedetti, Celso Eduardo ^[1]

Afiliação do(s) autor(es)

^[1] Brazilian Synchrotron Light Lab, Ctr Mol & Struct Biol, BR-13083970 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Plant Science; v. 177, n. 3, p. 190-195, SEP 2009.
• Citações Web of Science: 24

Resumo

Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus canker, a disease characterized by hyperplastic lesions on the host surface. We have shown previously that Xac strongly increases transcription of sweet orange (Citrus sinensis) genes encoding cell-wall remodeling enzymes and proteins associated with cell division and expansion. In addition, a number of Xac-regulated genes are implicated in the synthesis, mobilization and signaling of auxin and gibberellin. Since auxin and gibberellin control cell division and elongation and are known to modulate the expression of cell-wall hydrolytic enzymes, we examined their ability to modulate the transcription of the cell-wall remodeling genes altered by Xac. Indeed, the expression of various citrus cellulases, pectinesterases, expansin and galactosyltransferase was rapidly and similarly affected by auxin and gibberellin. Moreover, the changes in transcript levels of the cell-wall remodeling genes mediated by auxin and gibberellin correlated with changes in the expression of genes involved in gibberellin synthesis, auxin signaling and mobilization, as observed during Xac infection. Most significantly, auxin promoted canker development whereas an inhibitor of auxin transport reduced pustule formation. Interestingly, an inhibitor of gibberellin synthesis significantly inhibited the auxin-induced transcription, as well as the appearance of canker lesions, thus suggesting that a crosstalk between auxin and gibberellin controls the transcription of orange genes involved in cell division and expansion trigged by Xac. (C) 2009 Elsevier Ireland Ltd. All rights reserved. (AU)

• Processo FAPESP: 00/10266-8 - A structural biology laboratory network for the study of the 3D structures of proteins
• Beneficiário: Nilson Ivo Tonin Zanchin
• Modalidade de apoio: Auxílio à Pesquisa - Programa GENOMA
• Processo FAPESP: 03/08316-5 - Análise da expressão diferencial de genes de citrus em resposta a infecção por Xanthomonas axonopodis pv. citri e Xanthomonas axonopodis pv. aurantifolii
• Beneficiário: Celso Eduardo Benedetti
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 98/14138-2 - Center for Structural Molecular Biotechnology
• Beneficiário: Glaucius Oliva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs