Mitochondrial pentatricopeptide repeat(PPR)-containing proteins are essential to sustain embryogenesis in Arabidopsis thaliana

MARCHETTI MARIA FERNANDA, CORDOBA JUAN PABLO, PAGNUSSAT GABRIELA, ZABALETA EDUARDO

Mar del Plata

Congreso; XV Congreso Latinoamericano XXX Reunión Argentina de Fisiología Vegetal; 2014

Sociedad Argentina de Fisiología Vegetal

One of the largest gene families of the plant genome encodes proteins characterized by tandem arrays of pentatricopeptide repeats(PPRs) composed by characteristic 35 aminoacid motifs. The family has greatly expanded in higher plants (450 members in Arabidopsis) but also it has been found in animal and fungal proteins. PPR proteins are sequence-specific RNA-binding proteins implicated in many aspects of RNA process ing primarily in organelles. We focused on the role of PPR proteins potentially involved in embryo development. Phenotypes of four T-DNA insertion mutants for three genes encoding PPR-containing proteins (At2g02150:PPR2-1 and PPR2-2mutants; At1g79490:PPR7-1 mutant and gene At3g29290:PPR8-1mutant) were analyzed by DIC microscopy. These mutants show a delayed embryo development: siliques from heterozygous plants contain around 25% of globular to early heart stage embryos segregating from completely mature embryos. Consistent with this, we were unable to obtain homozygous mutant plants suggesting embryo lethality. Additionally, transient transformation of tobacco leaf epidermal cells showed these PPR proteins fused to GFP are localized in mitochondria.