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The iron-sulfur subunit (SDH2) of succinate dehydrogenase plays a key role in electron transport in plant mitochondria. However, it is yet unknown whether <i>SDH2</i> genes are involved in leaf senescence and yield formation. In this study, we isolated a late premature senescence mutant, <i>lps1</i>, in rice (<i>Oryza sativa</i>). The mutant leaves exhibited brown spots at late tillering stage and wilted at the late grain-filling stage and mature stage. In its premature senescence leaves, photosynthetic pigment contents and net photosynthetic rate were reduced; chloroplasts and mitochondria were degraded. Meanwhile, <i>lps1</i> displayed small panicles, low seed-setting rate and dramatically reduced grain yield. Gene cloning and complementation analysis suggested that the causal gene for the mutant phenotype was <i>OsSDH2-1</i> (<i>LOC_Os08g02640</i>), in which single nucleotide mutation resulted in an amino acid substitution in the encoded protein. <i>OsSDH2-1</i> gene was expressed in all organs tested, with higher expression in leaves, root tips, ovary and anthers. OsSDH2-1 protein was targeted to mitochondria. Furthermore, reactive oxygen species (ROS), mainly H₂O₂, was excessively accumulated in leaves and young panicles of <i>lps1</i>, which could cause premature leaf senescence and affect panicle development and pollen function. Taken together, <i>OsSDH2-1</i> plays a crucial role in leaf senescence and yield formation in rice.