MITOCHONDRIAL PPR-CONTAINING PROTEINS ARE ESSENTIAL IN EMBRYO DEVELOPMENT IN Arabidopsis thaliana

MARCHETTI, MARIA FERNANDA; CORDOBA JUAN PABLO; GLASS FRANZISKA; BRENNICKE AXEL; PAGNUSSAT G; EDUARDO JULIAN ZABALETA

Rosario

Congreso; L Reuniòn Anual SAIB; 2014

PPRs containing proteins are characterized by a motif of a degenerate 35-amino acid repeat. Most PPRs proteins are specific RNA-binding proteins which are involved in RNA processing, including editing, maturation, stability, and translation. We focused on the role of PPR proteins potentially involved in embryo development. Four T-DNA insertion mutants encoding for three PPR proteins (At2g02150, At1g79490 and At3g29290) were analyzed. Transient transformation with these PPR proteins fused to GFP showed they are localized in mitochondria. Mature siliques of mutants in these genes showed ~25% of shriveled seeds which do not germinate, not even in MS sucrose medium, suggesting embryo lethality. As we were unable to obtain homozygous mutant plants, silencing assays were developed with two independent artificial microRNAs for each gene. Mature siliques of silenced plants in a ~70% were preliminary analyzed. Most siliques were short length, containing aborted embryos. To further investigate this phenotype, we examined female and male gametophyte development. Apparently, embryo sac and pollen grain development proceeded normally. These results suggest that the expression of these mitochondrial PPR genes are essential to sustain embryo development and the proteins encoded may probably affect processes related to fertilization in Arabidopsis thaliana.