N-acetyltransferase 10 catalyzes RNA N⁴-acetylcytidine to regulate photosynthesis in rice

N⁴-acetylcytidine (ac⁴C) is a novel mRNA modification that enhances RNA stability and translation in mammals and plants. We previously identified ac⁴C in Arabidopsis, introduced by two homologs of human N-acetyltransferase 10 (NAT10). While ac⁴C influences leaf development in Arabidopsis, its role in rice is unclear. In this study, we identify OsNAT10 as the ac⁴C writer in rice. osnat10 mutants show developmental defects, including shorter roots, fewer tillers, and lower yield. Compared with wild type, ac⁴C-modified genes are less abundant in osnat10, particularly those related to photosynthesis. Additionally, osnat10 exhibits decreased photosynthetic capacity and reduced RNA stability and translation efficiency of ac⁴C target genes, like LIGHT-INDUCED RICE 1 (LIR1). Overexpressing OsLIR1 partially rescues osnat10 defects, underscoring OsNAT10's role in photosynthesis regulation. Our findings highlight ac⁴C's crucial function in photosynthesis and plant development, offering insights into epitranscriptomic modifications for crop improvement.