The Pentatricopeptide Repeat Protein OsPPR674 Regulates Rice Growth and Drought Sensitivity by Modulating RNA Editing of the Mitochondrial Transcript ccmC

The P-type pentatricopeptide repeat (PPR) proteins are crucial for RNA editing and post-transcriptional regulation in plant organelles, particularly mitochondria. This study investigates the role of <i>OsPPR674</i> in rice, focusing on its function in mitochondrial RNA editing. Using CRISPR/Cas9 technology, we generated <i>ppr674</i> mutant and examined its phenotypic and molecular characteristics. The results indicate that <i>ppr674</i> exhibits reduced plant height, decreased seed-setting rate, and poor drought tolerance. Further analysis revealed that in the <i>ppr674</i> mutant, RNA editing at the 299th nucleotide position of the mitochondrial <i>ccmC</i> gene (C-to-U conversion) was abolished. REMSAs showed that GST-<i>PPR674</i> specifically binds to RNA probes targeting this <i>ccmC</i>-299 site, confirming its role in this editing process. In summary, these results suggest that <i>OsPPR674</i> plays a pivotal role in mitochondrial RNA editing, emphasizing the significance of PPR proteins in organelle function and plant development.