IIB   20738
INSTITUTO DE INVESTIGACIONES BIOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A female gametophytic mutant impaired in a mitochondrial Mn-SOD -oiwa- reveals crucial roles for ROS during embryo sac development and fertilization in Arabidopsis thaliana.
Autor/es:
MARTIN, MARÍA VICTORIA; FIOL, DIEGO FERNANDO; VENKATESAN SUNDARESAN; ZABALETA, EDUARDO JULIÁN; PAGNUSSAT, GABRIELA CAROLINA
Lugar:
Rosario, Santa Fe
Reunión:
Congreso; 8th International Conference for Plant Mitochondrial Biology; 2013
Institución organizadora:
International Conference for Plant Mitochondrial Biology
Resumen:
Reactive oxygen species (ROS) can work as signaling molecules, regulating key aspects of plant development, or as toxic compounds leading to oxidative damage. In the present work, we show by the use of specific probes and confocal and DIC microscopy that control of ROS levels during megagametogenesis is largely dependent on OIWA, a mitochondrial Mn-superoxide dismutase. WT mature embryo sacs show ROS exclusively in the central cell, which appears to be the main source of ROS before pollination. Accordingly, expression of OIWA shows a complementary pattern. OIWA expression is maintained elevated in the egg apparatus at maturity, but is downregulated in the central cell. oiwa mutants are characterized by high levels of ROS detectable both in the central cell and in the micropylar cells of the embryo sacs. Remarkably, egg apparatus cells in oiwa show central cell features, indicating that high levels of ROS might result in the expression of central cell-characteristic genes. Notably, ROS are detected in the synergid cells after pollination. This ROS burst depends on stigma pollination but precedes fertilization, suggesting that embryo sacs sense the imminent arrival of pollen tubes and respond generating an oxidative environment. Altogether, we show that ROS play a crucial role during female gametogenesis and fertilization. Furthermore, OIWA activity seems critical for maintaining ROS localization confined to the central cell and essential for embryo sac patterning.