Required for specific RNA editing events in chloroplasts and stabilizes specific chloroplast mRNAs. Associates with the 3'-terminus ndhF mRNAs and protects them against 3'-exonucleolytic degradation (PubMed:19297624, PubMed:23110894). Required for normal chloroplast development under cold stress conditions by stabilizing transcripts of numerous mRNAs under these conditions (PubMed:23110894). May modulate telomere replication through RNA binding domains (PubMed:14703514). ADP-ribosylated by the Pseudomonas syringae type III effector HopU1. ADP-ribosylation reduces the ability of the protein to bind RNA. No visible phenotype under normal growth conditions, but mutant plants exhibit multiple specific editing defects in chloroplast transcripts (PubMed:19297624, PubMed:23110894). Mutant plants have increased sensitivity to cold stress (PubMed:23110894).