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Title: Two organelle RNA recognition motif proteins affect distinct sets of RNA editing sites in the Arabidopsis thaliana plastid

Plastid and mitochondrial RNAs in vascular plants are subjected to cytidine‐to‐uridine editing. The model plant speciesArabidopsis thaliana(Arabidopsis) has two nuclear‐encoded plastid‐targeted organelle RNA recognition motif (ORRM) proteins: ORRM1 and ORRM6. In theorrm1mutant, 21 plastid RNA editing sites were affected but none are essential to photosynthesis. In theorrm6mutants, two plastid RNA editing sites were affected:psbF‐C77 andaccD‐C794. BecausepsbFencodes the β subunit of cytochromeb559in photosystem II, which is essential to photosynthesis, theorrm6mutants were much smaller than the wild type. In addition, theorrm6mutants had pale green leaves and reduced photosynthetic efficiency. To investigate the functional relationship between ORRM1 and ORRM6, we generatedorrm1 orrm6double homozygous mutants. Morphological and physiological analyses showed that theorrm1 orrm6double mutants had a smaller plant size, reduced chlorophyll contents, and decreased photosynthetic efficiency, similar to theorrm6single mutants. Although theorrm1 orrm6double mutants adopted the phenotype of theorrm6single mutants, the total number of plastid RNA editing sites affected in theorrm1 orrm6double mutants was the sum of the sites affected in theorrm1andorrm6single mutants. These data suggest that ORRM1 and ORRM6 are in charge of distinct sets of plastid RNA editing sites and that simultaneous mutations inORRM1andORRM6genes do not cause additional reduction in editing extent at other plastid RNA editing sites.

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Author(s) / Creator(s):
 ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Plant Direct
Medium: X
Sponsoring Org:
National Science Foundation
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