CONICET | Buscador de Institutos y Recursos Humanos

Plant embryogenesis involves a regular sequence of cell division, differentiation and morphogenesis. Defects in mitochondrial proteins often show embryo lethal phenotypes suggesting that the mitochondria biogenesis is one of the key factors for normal embryo development. We are interested in the role of mitochondrial Pentatricopeptide Repeat (PPR) containing proteins during embryogenesis. Two allelic mutants for At2g02150 (EMB2794) gene are being studied. Mutant plants show ~25% of shriveled seeds in mature siliques. Gene silenced plants were developed by using two independent artificial microRNAs. Due to PPR proteins are sequence-specific RNA-binding proteins involved in many aspects of RNA processing primarily in organelles, the mitochondrial transcriptome profile was analyzed by qRT-PCR in silenced plants. Results show reduced expression levels of all exons of nad1 transcript (mitochondrially encoded Complex I subunit NAD1). Due to embryo lethality phenotype, homozygous mutant plants could not be obtained. Shriveled seeds could be rescued in MS sucrose medium and RNA from leaves was used to analyze the expression of nad1exon1 transcript by qPCR. As we are mainly interested in embryogenesis, we also analyzed nad1exon1 transcript expression levels in homozygous embryos. In both cases, results show a strong reduction in relative expression levels of nad1exon1 suggesting that this PPR protein affects nad1 transcript processing. To analyze the binding site of EMB2794 protein of nad1 transcript, we performed a protein-RNA binding assay using heterologous expressed protein. Preliminary results show that nad1intron1 is the target RNA of this protein, suggesting that EMB2794 protein could be a component of nad1 spliceosome.