A temperature-sensitive complex formed by OsDYW2 is required for chloroplast RNA editing and splicing under high temperature in rice

Abstract

Chloroplast gene expression and regulation are essential for plant growth, development, and environmental adaptation, in which post-transcriptional RNA editing and splicing processing play an important role. This study demonstrates that OsDYW2, a rice DYW domain-containing protein, is crucial for both chloroplast RNA editing and splicing, particularly under high temperature. Mutants lacking OsDYW2 exhibit a high-temperature-sensitive albino lethal phenotype, characterized by defective chloroplast biogenesis and suppressed expression of chloroplast development and photosynthesis-associated genes. The loss of OsDYW2 function impairs the RNA editing of matK-1258, ndhA-473, ndhA-563, ndhA-1070, ndhB-586, ndhB-611, ndhB-737, ndhB-830, ndhD-878, ndhG-5-UTR-10, ndhG-347, rpl2-2, rpoC2-4106, and rps14-80 sites as well as the RNA splicing of atpF, ndhA, ndhB, petB, rpl2, rps12, and rps16 under high-temperature conditions. Mechanistically, OsDYW2 interacts with core RNA processing factors, including several rice multiple organellar RNA editing factor (OsMORF) proteins, to form a temperature-sensitive complex. These interactions are modulated by high temperature, suggesting a direct link between high-temperature response and chloroplast RNA processing. Our findings demonstrate that OsDYW2 is essential for coordinating chloroplast post-transcriptional gene expression regulation with the high-temperature stress response in rice, providing new insights into the molecular mechanisms underlying chloroplast adaptation to environmental challenges.