Advances and prospects of plant mitochondrial pentatricopeptide repeat proteins in post-transcriptional processing

The pentatricopeptide repeat (PPR) protein is integral to various post-transcriptional processing functions of precursor RNA in plant mitochondria and plastids. It plays a significant role in seed development, plant growth and development, and male infertility, thereby influencing crop yield and hybrid breeding. Over the past 30 years, significant progress has been achieved in elucidating the molecular functions and mechanisms of PPR proteins in various species, including Arabidopsis, maize, rice, and moss. Here, we provide a comprehensive summary of advances in the role of plant mitochondrial PPRs in post-transcriptional regulation, focusing on RNA editing, intron splicing, stability of 3′ untranslated regions (UTRs), maturation of 5' UTRs as well as RNA translation. Additionally, we discuss the potential applications of engineered PPR proteins in crop breeding and outline future research directions to resolve the outstanding questions surrounding the molecular mechanisms of PPR proteins.