Abstract
The plastid genome in higher plants is transcribed by NEP (T7-phage type RNA polymerase) and PEP (bacterial type RNA polymerase). Plastidic accD and rpo genes are exclusively transcribed by NEP, whereas photosynthetic genes are mainly transcribed by PEP. Gene expression is primary determined by transcription level, but in plastids post-transcriptional regulations like RNA editing, trimming and splicing of immature RNAs are also crucial for correct and enough expression of functional RNAs or active proteins. We focused in an Arabidopsis PPR gene named PPRTp, because the major NEP (RPOTp) and PPRTp show highest correlation coefficient with each other in ATTED-II database. An Arabidopsis pprTp mutant showed albino and severe morphological deficiency. We found that an RNA editing in accD mRNA did not occur in this mutant. We will discuss the critical role of PPRTp mediated by the RNA editing of accD mRNA.
