OsALY4 acts as an m5C-mRNA reader facilitating mRNA export and contributing to chilling and salt tolerance in rice

RNA 5-methylcytosine (m 5 C) modification is involved in various developmental processes and stress tolerance. However, its role in abiotic stress responses remains largely unknown in rice. We previously demonstrated that the writer OsNSUN2 is required for heat adaptation by facilitating the translation of m 5 C-mRNAs. Herein, we identify OsALY4 as an m 5 C reader to modulate the chilling and salt tolerance in rice seedlings. The interaction between OsALY4 and RNA helicase OsAIP2 is essential for nucleocytoplasmic export of target mRNAs of OsALY4 under normal condition, including those of OsWRKY45 , OsMDHAR3 , and OsHAK13 . In the osaly4 mutant, these target mRNAs are more efficiently transported to cytoplasm under stress conditions due to the high expression of OsALY2 and OsALY6 , which affect chilling and salt tolerance through several pathways. Our findings uncover the critical function of m 5 C modification on mRNA transport and stress adaptation in rice, shedding new light on the intricate mechanisms underlying plant resilience.