mRNA decapping proteins regulate EIN2-dependent ethylene signaling in arabidopsis

Ethylene signaling regulates plant growth and stress adaptation through a well-defined pathway, yet its mechanistic complexity remains underexplored. Here, we identify two mRNA decapping proteins, DCP1 and DCP2, as novel regulators of canonical ethylene signaling. Using forward genetics in the ctr1-1 loss-of-function mutant (constitutively activated ethylene signaling), we identified dcp1 and dcp2 suppressor mutations that significantly rescue the developmental defects characteristic of ctr1-1. Transcriptome profiling showed that DCP1/2 regulates a substantial subset of genes that are affected by CTR1 or ACC treatment. We further found that both DCP1 and DCP2 were associated with the C-terminal of central regulator EIN2 (EIN2-C) in processing bodies (P-bodies). These dcp mutants exhibit reduced protein accumulation of the key transcription factor EIN3, suggesting a potential link to the EIN2-C-mediated translational regulation of EBF1/2 mRNAs. Additionally, we showed that the EMS-induced M78I mutation in DCP1 disrupts its interaction with DCP2, impairing DCP1-activated decapping activity of DCP2 in vitro, while the R138H mutation in DCP2 directly compromises both its enzymatic activity and the association with EIN2-C. Our findings provide genetic evidence that mRNA decapping machinery is involved in ethylene signaling and suggest a potential link to the EIN2-C-mediated pathway within P-bodies.