Regulation of m⁶A RNA reader protein OsECT3 activity by lysine acetylation in the cold stress response in rice

N⁶-Methyladenosine (m⁶A) reader proteins, which recognize m⁶A to regulate RNA metabolism, are important for plant adaptation to the changing environment. It remains unknown how the activities of plant m⁶A reader proteins are regulated in plant responses to stress. Here we show that the rice m⁶A reader protein EVOLUTIONARILY CONSERVED C-TERMINAL REGION 3 (OsECT3), required for rice tolerance to cold, is post-translationally modified by lysine acetylation, which reduces its m⁶A-binding activity. Under cold conditions, OsECT3 acetylation is reduced by cold-induced histone deacetylase HDA705 and low ACLA2-sourced acetyl-CoA levels, resulting in an increase in OsECT3 m⁶A-binding activity, the accumulation of cold-response-related mRNAs and improved tolerance of rice to cold stress. These results unravel a regulatory mechanism of an m⁶A reader protein to dynamically control m⁶A RNA levels under stress and suggest a link between lysine acetylation, metabolism and m⁶A pathways.