AtMBF1 genes modulate the seed thermotolerance and germination responses against oxidative stress conditions.

ARCE D; TONÓN C; GODOY AV; CASALONGUÉ C

Pinamar

Congreso; Reunión Anual SAIB; 2005

SAIB

ATMBF1 GENES MODULATE THE SEED THERMOTOLERANCE AND GERMINATION RESPONSES AGAINST OXIDATIVE STRESS CONDITIONS Arce, Débora; Tonón, Claudia; Godoy, Verónica and Casalongué, Claudia. Instituto de Investigaciones Biológicas, FCEyN, UNMDP, 7600, Mar del Plata, Buenos Aires, Argentina. E-mail: dparcear@yahoo.com.ar  Multiprotein bridging factor 1 (MBF1) is a transcriptional co-activator that mediates transcriptional activation by bridging between an activator and the TATA-box binding protein. To better understand the roles of MBF1 genes during the response against oxidative stress  and thermotolerance, we carried out the analysis of different Arabidopsis thaliana MBF1 mutant lines: T-DNA insertion mutants (SALK and Syngenta collections) and transgenic over-expressing  lines for the three AtMBF1 genes (a, b or c). Plants homozygous for the T-DNA insertion in AtMBF1c and the triple mutant (AtMBF1abc), were treated with methyl viologen or heat shock.  Seeds showed a delay in the germination rate compared to the wild type after treatments. However, the over-expressing lines (35S::AtMBF1 b and c) showed a higher germination rate than the wild type seeds under the same stress conditions. All these findings suggest that AtMBFs genes may modulate the response to oxidative stress and heat-induced oxidative damage during germination by a still unkown mechanism. Supported by ANPCyT, CONICET, UNMDP.