RNA metabolism and transcript regulation

Mitochondria house the tricarboxylic acid (TCA) cycle, the oxidative phosphorylation (OXPHOS) machinery and are also the sites of numerous other essential metabolic pathways in plants. This chapter describes the principal components of the transcription and post-transcriptional regulatory steps in mitochondrial gene expression. It then summarizes the current state of knowledge of mitochondrial RNA processing and maturation in plants. The chapter also describes the main pathways of ribosome maturation in bacteria and plant mitochondria. It reviews recent significant progress in editing factors research in plant mitochondria. Furthermore the chapter focuses on group I and group II introns that are predominant in angiosperm mitochondria. Analysis of group II introns splicing in wheat mitochondria indicates multiple group II splicing mechanisms, as evidenced by the presence of linear and circular forms of excised intron molecules in vivo. The splicing of group II introns is mechanistically identical to that of the nuclear spliceosomal introns.