Mitochondrial Ribosomal Protein S9M is Involved in Male Gametogenesis and Seed Development in Arabidopsis.

Mitochondrial function is critical for cell vitality in all eukaryotes including plants. Although plant mitochondria contain many proteins, few have been studied in the context of plant development and physiology. We used knock-down mutantRPS9Mto study its important role in male gametogenesis and seed development inArabidopsis thaliana. Knock-down ofRPS9Min therps9m-3mutant led to abnormal pollen development and impaired pollen tube growth. In addition, both embryo and endosperm development were affected. Phenotype analysis revealed that therps9m-3mutant contained a lower amount of endosperm and nuclear proteins, and both embryo cell division and embryo pattern were affected, resulting in an abnormal and defective embryo. Lowering the level of RPS9M inrps9m-3affects mitochondrial ribosome biogenesis, energy metabolism and production of ROS. Our data revealed that RPS9M plays important roles in normal gametophyte development and seed formation, possibly by sustaining mitochondrial function.