, Encoding a Pentatricopeptide Repeat Protein, Is Essential for Chloroplast RNA Editing and Biogenesis in Soybean.

Chloroplast biogenesis and development are highly complex processes requiring interactions between plastids and nuclear genomic products. Pentatricopeptide repeat (PPR) proteins play an essential role in the development of chloroplasts; however, it remains unclear how RNA editing factors influence soybean development. In this study, a mutant () was identified with decreased chlorophyll contents. Genetic mapping revealed that a single-nucleotide deletion at position 1949 bp in the gene in the mutant, resulting in a truncated GmPGL2 protein. The nuclear-encoded is a PLS-type PPR protein that localizes to the chloroplasts. The C-to-U editing efficiencies of , , , , , and were reduced in the mutant. RNA electrophoresis mobility shift assay (REMSA) analysis further revealed that GmPGL2 binds to the immediate upstream sequences at RNA editing sites of and , respectively. In addition, GmPGL2 was found to interact with GmMORF8, GmMORF9, and GmORRM6. These results suggest that GmPGL2 participates in C-to-U RNA editing the formation of a complex RNA editosome in soybean chloroplasts.