Down-regulation of auxin signalling pathway enhances antioxidant metabolism as an adaptative response to salt stress in Arabidopsis

IGLESIAS, MARÍA JOSÉ; TERRILE, MARÍA CECILIA; BARTOLI, CARLOS GUILLERMO; D´IPPOLITO, SEBASTIÁN; CASALONGUÉ, CLAUDIA

La Plata

Congreso; XXVIII Reunión Argentina de Fisiología Vegetal; 2010

Asociación Sociedad Argentina de Fisiología Vegetal

The sessile life style of plants makes them vulnerable to changing environmental conditions.Salinization is a problem long being associated to agriculture. The aim of this work was to study how auxin contributes to plant´s ability to grow under changing conditions. The phytohormone auxin regulates gene expression through direct physical interaction with TIR1/AFB receptor proteins. We have previously reported that Arabidopsis double mutant for auxin receptors, tir1 afb2is rather tolerant to abiotic stresses. In this work we analyzed the effect of salinity by analyzing the auxin-inducible gene expression in the BA3:GUS transgenic line. Salinity mediated by NaCl treatments significantly inhibited the expression of BA3:GUS reporter in a dose-response manner.tir1 afb2 plants showed significantly reduced ROS accumulation as well as high levels of ascorbic acid and antioxidant enzymatic activities. In addition, auxin transport decreased under salt stress.Our evidences revealed that auxin is fundamentally required to redistribute growth and development responses meanwhile improve the adaptative response against changing salinity.The cross-talk between auxin and redox-status is emerging as a new regulatory node by which plants control acclimation responses to environmental stresses.Partially supported by CONICET; UNMDP.