Descripción
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The Arabidopsis heterotrimeric G protein complex regulates several developmental-associated processes and innate immunity responses to vascular and necrotrophic fungal pathogens1. G protein has three protein subunits ?, ? and ?, encoded by AGB1, GPA1 and AGG1/AGG2 genes respectively2. AGB1 forms an obligate dimer with either one of the two Arabidopsis G? subunits (?AGG1 and ?AGG2)2. Accordingly, we have now demonstrated that the agg1 agg2 double mutant was as susceptible as agb1 plants to the necrotrophic fungus Plectosphaerella cucumerina. To elucidate the molecular bases of heterotrimeric G protein-mediated resistance, we performed a comparative transcriptomic analysis of agb1-1 mutant and wild-type plants upon inoculation with P. cucumerina. This analysis, together with gene expression and metabolomic studies, demonstrated that G protein-mediated resistance was independent on the salicylic acid (SA)-, jasmonic acid (JA)-, ethylene (ET)-, abscisic acid (ABA)- or tryptophan-derived metabolites defensive signalling, as these pathways required for resistance to necrotophs were not impaired in agb1-1 and agg1 agg2 plants. Notably, in agb1-1 transcriptome we found an overrepresentation of misregulated genes related with cell wall functions, which showed a similar expression pattern in agg1 agg2 plants. Biochemical analyses and Fourier Transform InfraRed (FTIR) spectroscopy of cell walls from G-protein mutants and wild-type plants revealed that xylose content was lower in agb1 and agg1 agg2 mutants that in wild-type plants, and that these mutants walls had similar FTIR spectratypes, which differed from that of wild-type plants. The data presented here suggest a canonical functionality of the G? and G?1/?2 subunits in the control of Arabidopsis immune responses and cell wall composition, being this last critical for resistance to necrotrophic fungal pathogens. | |
Internacional
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Si |
Nombre congreso
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Communication in Plants and their Responses to the Enviroment |
Tipo de participación
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960 |
Lugar del congreso
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Halle (Alemania) |
Revisores
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Si |
ISBN o ISSN
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0000-0000 |
DOI
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Fecha inicio congreso
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19/05/2011 |
Fecha fin congreso
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22/05/2011 |
Desde la página
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0 |
Hasta la página
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0 |
Título de las actas
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Libro de resúmenes |