CHARACTERIZATION OF A FEMALE GAMETOPHYTIC MUTANT IN Arabidopsis thaliana

IGLESIAS, M.J.; TOSSI, V; GERGOFF, G; LARRAMBURU, E; GONZALEZ, M.E.; LOBATO, C.; ZABALETA, E.

San Miguel de Tucumán

Congreso; XLV Reunión Anual SAIB; 2009

Development and function of gametophytes are crucial for plantreproduction. However, relatively little is known about themolecular basis of embryo sac development. We characterized aDs insertion line (MEE 42) with defects in female transmissionefficiency. The phenotype of MEE 42 was studied by DICmicroscopy of whole-mount preparations of ovules. Mutant ovuleswere found to be affected during post-pollination processes.Embryo development was arrested at one-cell zygotic stage.Endosperm development was also arrested. Some ovules appearedunfertilized, suggesting that the mutation is also affecting pollentube (PT) guidance or fertilization. To further study the nature ofthe fertilization failure, we analyzed PT growth patterns by anilineblue staining. Although pollen tubes were found at the micropyle ofboth WT and mutant ovules, some mutant ovules showed abnormalPT growth patterns. To characterize the identity of the synergidecells -responsible for PT attraction- we tested the expression of asynergide marker. Similar GUS staining patterns were observed inWT and MEE42 mutant embryo sacs. The flanking sequence of theDs element was confirmed for the 5’ end of the DS element byusing Ds and specific primers to be in At3g63080, encoding aglutathione peroxidase.