Abstract
One of the regulation factors of mitochondrial gene expression is pentatricopeptide repeat (PPR) protein which binds RNA. PPR motif is composed of 35 amino acids tandem repeat and PPR proteins bind specific RNA. Consequently, PPR proteins are involved in post transcriptional process. In this study, we analyzed rice PPR gene mutant, named Mitochondrial PPR 25 (MPR25) caused by Tos17 insertio. mpr25 mutants exhibited pale green leaves and growth retardation. MPR25 was localized in mitochondria and was involved in C-U RNA editing of nad5 encoding a subunit of complex I (NADH dehydrogenase) respiratory chain in mitochondria. Respiration activity was not significantly lower in the mpr25 mutants but photosynthesis rate was lower in the mpr25 mutants than that of WT at juvenile stage. Internal/external NADH dehydrogenase genes were up-regulated in mpr25 mutant leaves than those of WT at juvenile stage. MPR25 have a function of C-U RNA editing of nad5 and affects photosynthesis.
