INVESTIGADORES
OTTADO Jorgelina
congresos y reuniones científicas
Título:
EFFECTS OF MUTATIONS IN THE Xanthomonas axonopodis pv citri LIPOPOLYSACCHARIDE ON CITRUS CANKER
Autor/es:
SILVANA PETROCELLI; CASABUONO, AC; COUTO, AS; JORGELINA OTTADO; ORELLANO, E
Lugar:
Villa Carlos Paz
Reunión:
Congreso; XLIV Reunión Anual de la Sociedad Argentina de Bioquímica y Biología Molecular; 2008
Resumen:
A broad range of pathogens is recognized by plants through socalled
pathogen-associated molecular patterns (PAMPs), which are
highly conserved fragments of pathogenic molecules. In plant
pathogenic bacteria, lipopolysaccharide (LPS) is an important
virulence factor and it is being recognized as a PAMP. Stomatal
closure is part of a plant innate immune response. Citrus canker is
produced by Xanthomonas axonopodis pv. citri (Xac).
The aim of this study is to determine the effect of Xac mutant strains
defective in genes (wzt and rfb303) involved in LPS biosynthesis on
citrus canker. The structures of LPS from Xac-wzt and Xac-rfb303
were determined and differences between LPS from Xac and
mutants strains were observed. Incubation of orange leaves with
LPS isolated of Xac wild-type (wt), Xac-wzt and Xac-rfb303
induced stomatal closure after 2 hours. On the other hand,
incubation of orange leaves with bacteria induced stomatal aperture
after 3 hours. It is established that bacterial LPS can induce
accumulations of transcripts of a number of defense-related genes
like PR, PrxA, GST and MAPKs in plants. Expression changes in
genes that are involved in basal defense were observed in orange
leaves infected with Xac wt, Xac-wzt and Xac-rfb303 at 6 and 24
hours post-infiltration. These results suggest that LPS of Xac acts as
a PAMP in Xac-orange interaction.