IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
BBX24 acts as a positive regulator to promote hypocotyl elongation in shade avoidance responses
Autor/es:
CROCCO, CARLOS; SANTIAGO MORA GARCIA; BOTTO, JAVIER
Lugar:
Mendoza
Reunión:
Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012
Institución organizadora:
Sociedad Argentina de Investigación en Bioquímica y Biología Molecular
Resumen:
Plants grown at high densities perceive through the phytochrome
system a decrease in the red to far-red (R:FR) ratio of incoming light,
as a warning signal of future competition, and mount morphological
responses collectively known as the shade avoidance syndrome
(SAS). In Arabidopsis thaliana seedlings, the hypocotyl elongation
by SAS involves a rapid up-regulation of known shade marker genes
activating an interacting network of various hormones that will
eventually lead to cell elongation. We identified and characterized a
group of B-box (BBX) proteins as new components involved in the
SAS signaling pathway, which act as positive (BBX18 and BBX24)
or negative (BBX19, BBX21 and BBX22) regulators. By
microarray analysis, pharmacological and genetic approaches, we
investigated the molecular action of BBX24 in the SAS. Global
expression analysis of wild-type and bbx24 seedlings reveals that a
large number of genes involved in hormonal signaling pathways are
positively regulated by BBX24 in response to shade, particularly
genes involved in gibberellin (GA) biosynthesis. We found that
exogenous GA recovers the hypocotyl elongation of bbx24 mutant
seedlings in shade conditions. In addition, the phenotype of pif4
bbx24 double mutants suggests that BBX24 is involved in the GA
signaling pathway mediated by PHYTOCHROME
INTERACTING FACTOR 4 (PIF4).