A Mutation of OSOTP 51 Leads to Impairment of Photosystem I Complex Assembly and Serious Photo‐damage in Rice

Abstract Gene expression in chloroplasts is regulated by many nuclear‐encoded proteins. In this study, we isolated a rice ( Oryza sativa subsp. japonica ) mutant osotp51 with significant reduction in photosystem I (PSI). The osotp51 is extremely sensitive to light and accumulates a higher level of reactive oxygen species. Its leaves are almost albino when grown at 40 μmol photons/m 2 per s. However, grown at 4 μmol photons/m 2 per s, osotp51 has a similar phenotype to the wild‐type. 77K chlorophyll fluorescence analysis showed a blue shift in the highest peak emission from PSI in osotp51 . In addition, the level of PSI and PSII dimer is dramatically reduced in osotp51 . OSOTP 51 encodes a pentatricopeptide repeats protein, homologous to organelle transcript processing 51 in Arabidopsis . Loss‐of‐function OSOTP51 affects intron splicing of a number of plastid genes, particularly the ycf3 coding a protein involved in the assembly of PSI complex. OSOTP51 is functionally conserved in higher plants. The mutation of osotp51 indirectly leads to a widespread change in the structure and functions of PSI, results in severe photoinhibition, and finally dies, even when grown under very low light intensity.