Patterning and fertilization of the embryo sac in Arabidopsis thaliana

DISTEFANO, AYELEN; BELLIDO, ANDRES; MARTIN, MARIA VICTORIA; FIOL, DIEGO F.; ZABALETA, EDUARDO J.; PAGNUSSAT, GABRIELA C.

Rosario

Conferencia; Reunion SAIB 2014; 2014

Gamete formation in plants takes place in special haploid structures called gametophytes.The male gametophyte is the pollen grain, while the female gametophyte is the embryosac, which develops enclosed by the maternal tissues of the ovule. In Arabidopsis, theembryo sac is a polarized structure composed by seven cells: the egg cell, the central cell,two synergids and three antipodal cells. In our lab, we are interested in the molecularmechanisms underlying cell specification during embryo sac development. Particularly, weare focusing our studies on mitochondrial proteins. By studying insertional mutants ingenes encoding ROS detoxifying enzymes, we showed a crucial role for ROS in cell fateand fertilization. Additionally, we have identified and studied Arabidopsis mutants withinsertions in genes that encode for members of the mitochondrial electron shuttleAdrenodoxin-Adrenodoxin reductase (ADX-ADXR). These mutants show cell fateabnormalities and aberrant pollen tube attraction, suggesting a role for this shuttle in cellspecification and communication between the female and male gametophytes. Invertebrates and insects, ADX-ADXR mediates electron transfer to a cytochrome P450,which constitutes the first step in steroid hormones synthesis. We are currently analyzingthe possible occurrence of a similar pathway in Arabidopsis and the female gametophyte steroid profile. Suppported by ANPCyT, CONICET and HHMI