oiwa regulates ROS homeostasis and is essential for cell specification during embryo sac development in Arabidopsis thaliana

MARTIN, M. V.; PAGNUSSAT G; EDUARDO JULIAN ZABALETA

Mar del Plata

Congreso; Reunión de Fisiología Vegetal; 2012

Reactive oxygen species (ROS) are emerging signaling molecules that regulate manydevelopmental and physiological responses in diverse organisms. In plants, ROS areimplicated in a wide range of processes, including environmental responses, growth,cell elongation, apical dominance, tracheary element maturation, trichomedevelopment, senescence, programmed cell death and hormonal signaling. (Joo et al.,2001; Rodriguez et al., 2002; Foreman et al., 2003; Carol and Dolan, 2006; Gapper andDolan, 2006; Van Breusegem and Dat, 2006; Lee et al., 2007; Miller et al., 2008; DeTullio et al., 2010; Tsukagoshi et al., 2010). Furthermore, growing evidence issupporting a crucial role for ROS in plant cell division: ROS were reported to accelerateauxin-mediated cell cycle entry in Medicago sativa L (Attila Fehér, 2008) and to controlthe transition between cell proliferation and differentiation in Arabidopsis root(Tsukagoshi et al., 2010). On the other hand, ROS can also be cytotoxic, causingoxidative damage to cell structures and molecules and inducing cell death programs(Van Breusegem and Dat, 2006). This dual role of ROS acting as toxic agents or assignaling molecules is mainly dependent on concentration, pulse duration and site ofaction. ROS fluctuations and homeostasis are thus tightly regulated in the plant cell.Superoxide dismutases (SODs; EC 1.15.1.1) catalyze the dismutation of superoxide (O2–) to molecular oxygen (O2) and peroxide (H2O2) and are key components of the ROSgene network in plants. Here, by studying the Arabidopsis mutants oiwa, carryinginsertions in the Mn-SOD coding gene, we revealed a new role for Mn-SOD as anessential protein regulating ROS levels during female gametogenesis, which in turnresult critical for cell fate decisions throughout embryo sac development.