IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
XANTHOMONAS CAMPESTRIS SUPPRESSES STOMATAL DEFENSE
Autor/es:
GUDESBLAT GE; TORRES PABLO; VOJNOV ADRIAN
Lugar:
Villa Carlos Paz
Reunión:
Congreso; Sociedad Argentina de Microbiología General; 2008
Resumen:
Pathogen-induced stomatal closure is part of the plant innate
immune response. In order to penetrate leaves through stomata,
pathogens must avoid the stomatal response of the host. In this work
we describe a factor secreted by the bacterial phytopathogen
Xanthomonas campestris pv campestris (Xcc) that is capable of
interfering with stomatal closure induced by bacteria or by abscisic
acid (ABA). We found that living Xcc, as well as ethyl acetate
extracts from Xcc culture supernatants, are capable of reverting
stomatal closure induced by bacteria, lypopolisaccharide (lps) or
ABA. Xcc ethyl acetate extracts also complemented the infectivity
of Pseudomonas syringae pv tomato (Pst) mutants deficient in the
production of the coronatine (cor) toxin, which is required to
overcome stomatal defense. By contrast, the rpfF and rpfC mutant
strains of Xcc, that are unable to respectively synthesize or perceive
a diffusible molecule involved in bacterial cell to cell signaling,
were incapable of reverting stomatal closure, indicating that
suppression of stomatal response by Xcc requires an intact rpf/DSF
system. In addition, we found that guard cell-specific MAP kinase 3
(MPK3) Arabidopsis antisense mutants were unresponsive to
bacteria or lps in promotion of stomatal closure, and also more
sensitive to Pst cor deficient mutants, showing that MPK3 is
required for stomatal immune response.