TIR1 S-nitrosylation is a regulatory component in temperature-dependent Arabidopsis seedling growth

CASALONGUE, CLAUDIA ANAHI; TERRILE, MARÍA CECILIA; CASCO, AGUSTINA

Cordoba

Congreso; LII Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2016

SAIB

Plasticity allows plants to modulate their development in response to widely fluctuating environments. A mild increase in environmental temperature stimulates the growth of Arabidopsis seedlings by promoting biosynthesis of the plant hormone auxin. A recent study has revealed that the accumulation of auxin is only a part of the response. Temperature also promotes stabilization of the auxin co-receptor TIR1 through its interaction with the molecular chaperone HSP90. The aim of this work was to determine whether nitric oxide (NO) throughout S-nitrosylation of TIR1 is involved in the temperature-induced hypocotyl elongation in Arabidopsis. Plants overexpressing tir1 proteins mutated in cysteine residues targets of S-nitrosylation, tir1 C140A and tir1 C480A, showed an auxin-resistant response quantified as hypocotyl elongation. Temperature-induced phenotype was impaired in two different overexpressing transgenic lines of tir1 C140A. Although the introduction of tir1 C480A in the tir1-1 background partially restores auxin sensitivity, tir1 C140A did not recover TIR1 functionality. These data provided evidence about the relevance of post-translational modification in TIR1, and added a novel regulatory component in the temperature-dependent hypocotyl elongation. Supported by ANPCyT, CONICET and UNMdP.