IIB   20738
INSTITUTO DE INVESTIGACIONES BIOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
An essential role for nitric oxide in auxin signaling pathway
Autor/es:
TERRILE, MC; CALDERON-VILLALOBOS, LIA; IGLESIAS, MJ; PARIS, R; ESTELLE. M; LAMATTINA, L; CASALONGUÉ, CA
Lugar:
Puerto Madryn
Reunión:
Congreso; XLVI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2010
Institución organizadora:
Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)
Resumen:
Nitric
oxide (NO) is a second messenger implicated in many plant cell signaling
events. In particular, NO is a key molecule that operates in the
auxin-regulated signaling cascade contributing to root morphogenesis during
plant growth and development. S-nitrosylation is emerging as a specific
posttranslational protein modification for the transduction of NO bioactivity. Recently,
we demonstrated that NO production is induced in IAA-treated Arabidopsis roots.
NO is also required for the auxin-induced gene expression and auxin-induced
degradation of Aux/IAA repressors. Moreover, NO controls TIR1/AFB2-Aux/IAA
protein-protein interaction leading to Aux/IAA degradation and auxin-dependent
gene expression. Here, we demonstrate that the auxin receptor TIR1 is
S-nitrosylated. Mutations of cysteine residues, Cys 140 (C140A) and Cys 480
(C480A) in TIR1 protein disrupted its interaction with Aux/IAA repressors. Arabidopsis
transgenic lines overexpressing TIR1 protein in tir1-1 background rescued the
normal root sensitivity to auxin. However, when tir1 C140A was overexpressed,
TIR1 functionality was not recovered and seedlings remained resistant to auxin
suggesting that S-nitrosylation of this cysteine residue may be critical for
auxin signaling. These results open an exciting new field in the physiological
regulation of auxin signaling by NO. Supported by UNMdP, ANPCyT, CONICET, UCSD-USA.