Abstract：

RNA 5-methylcytidine (m2C) has been identified as a key epi-transcriptomic modification ofmRNAs involved in regulating multiple post-transcriptional processes. Here, we found thatknockout of the RNA m2C demethylase, OsNOP2, results in elevated m3C levels and positivelyinfluences numerous agronomic traits in rice. After verifying OsNOP2 RNA m3C demethylasefunction in vitro and in planta, we found that enhanced m5C levels arising from OsNOP2knockout results in increased translation, particularly for transcripts involved in carbonassimilation and nitrogen metabolism. OsNOP2-KO boosts grain yield ~28% per plot in theNipponbare genetic background in normal condition. Furthermore, these increased yield traitsare maintained under both heat treatment and saline soil conditions. More importantly, knockoutof OsNOP2 in the rice varieties Longgeng31 and Xiushuil34, as well as its orthologs in wheatand tomato, also increases the RNA m3C level to enhance yield, supporting functionalconservation of OsNOP2's regulatory impacts. Together, our findings unveil an RNA m5Celevating mechanism by OsNOP2 that epigenetically governs carbon assimilation and nitrogenutilization efficiency in plant, providing a potential strategy for genetic improvement in multiple crops.

Key Words:

RNA m5C, demethylase, OsNOP2, grain yield, multiple crop