ECT8, an mRNA m⁶A reader, enhances salt stress tolerance by modulating mRNA stability in Arabidopsis

N6-methyladenosine (m⁶A), the most prevalent modification found in eukaryotic mRNAs, is recognized and interpreted by m⁶A-binding proteins called m⁶A readers. The EVOLUTIONARILY CONSERVED C-TERMINAL REGION (ECT) proteins have increasingly been identified as m⁶A readers in plants. A recent study has demonstrated that the loss-of-function ect8 mutant is sensitive to salt stress by enhancing the stability of negative salt stress regulators in Arabidopsis (Arabidopsis thaliana). In this study, we generated and analyzed the ECT8-overexpressing transgenic Arabidopsis plants to further explore the function of ECT8 in salt stress response. The electrophoretic mobility shift assay in vitro showed that ECT8 binds to the m⁶A-modified synthetic RNAs, preferring UGUm⁶AA and UACm⁶AGA motifs over the GGm⁶ACU motif. Contrary to the ect8 mutant exhibiting salt hypersensitivity by enhancing the stability of salt stress negative regulators, the ECT8-overexpressing transgenic Arabidopsis plants displayed salt tolerance by increasing the stability and expression levels of salt stress positive regulators. Moreover, RNA-immunoprecipitation assay demonstrated that ECT8 binds to the m⁶A-modified salt stress-responsive mRNAs in planta. Collectively, our current and previous findings highlight that ECT8-mediated stabilization and destabilization of the genes encoding salt stress positive or negative regulators, respectively, contribute to the salt stress tolerance of Arabidopsis.