IIB   20738
INSTITUTO DE INVESTIGACIONES BIOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A mitochondrial ADX ? ADXR ? P450 shuttle is essential for gametophytic development in A. thaliana
Autor/es:
AYELEN M. DISTEFANO; EDUARDO J. ZABALETA; NICOLÁS SETZES; DIEGO F. FIOL; ANDRES M. BELLIDO; GABRIELA C. PAGNUSSAT
Lugar:
Buenos Aires
Reunión:
Congreso; LASDB Meeting 2019; 2019
Resumen:
Gametophytes are haploid structures where gametes are specified, which makes them essential for plant reproduction. We have identified and studied Arabidopsis mutants with an insertion in a nuclear gene encoding for a mitochondrial adrenodoxin reductase (ADXR) that have female gametophyte development defects. In mammals and insects mitochondria, adrenodoxin (ADX) mediates electron transfer from NADPH via ADXR towards a cytochrome P450 (P450), which constitutes the first step in steroid hormones synthesis. Through Y2H studies and bimolecular fluorescence complementation assays, we have established that three Arabidopsis P450s (CYP711A1, CYP90A1, CYP75B1) interact with ADX1. We demonstrated that these P450s have mitochondrial localization by co-localization experiments in N. benthamiana. However, knockout mutant lines for these P450s do not show gametophytic defects. Since this could be due to functional redundancy, we performed crossings to obtain double and triple mutants. We found that, despite double hemizygous mutants didn?t show any differences in their percentage of abortions, the triple hemizygous mutant showed ~8% of aborted seeds, suggesting a gametophytic defect. The analysis of its embryo sacs under DIC microscopy showed development defects similar to those found in ADXR mutants. Since homozygous mutants for CPD present development issues, the idea is to analyze the cyp711a1, CYP90A1/cyp90a1, cyp75b1 triple mutant, which should present a percentage of abortions close to 50%. Preliminary results showed that these triple mutants showed 35 - 48% of aborted seeds, which suggests a gametophytic defect. We are currently growing more plants in order to increase statistical power