Mitochondrial PPR proteins are essential to sustain embryogenesis in Arabidopsis thaliana

MARCHETTI, MARIA FERNANDA; CORDOBA JUAN PABLO; CAINZOS MAXIMILIANO; OSTERSETZER O; PAGNUSSAT G; EDUARDO JULIAN ZABALETA

Cordoba

Congreso; LII Reunión Anual SAIB; 2016

SAIB

Plant embryogenesis involves a regular sequence of celldivision, differentiation and morphogenesis. Defects inmitochondrial proteins often show embryo lethal phenotypessuggesting that the mitochondria biogenesis is one of the keyfactors for normal embryo development. We are interested in therole of mitochondrial PPR proteins during embryogenesis. Twoallelic mutants for At2g02150 (EMB2794) gene are beingstudied. Mutant plants show ~25% of shriveled seeds in maturesiliques. Homozygous mutants could not be obtained. Genesilenced plants were developed by using two independentartificial microRNAs. Due to PPR proteins are sequence-specificRNA-bindingproteins involved in many aspects of RNAprocessing primarily in organelles, the splicing profile of themitochondrial mRNAs was analyzed by quantitative RTPCRofmitochondrial transcripts in silenced plants. Results showsplicing defects for all exons of nad1 RNA (mitochondriallyencoded Complex I subunit NAD1), suggesting that EMB2794protein is a component of nad1 spliceosome. The annotation ofAt2g02150 locus has recently changed incorporating a secondsmall gene (At2g02148) covering the binding site of one of themicroRNAs. Due to the fact that both microRNAs are equallyeffective in silencing EMB2794 transcript, we propose that twodifferent overlapping mRNAs are being transcribed.