The importance of translational regulation during Arabidopsis seed germination has been shown previously. Here the role of transcriptional and translational regulation during seed imbibition of the very dormant DELAY OF GERMINATION 1 (DOG1) near-isogenic line was investigated. Polysome profiling was performed on dormant and after-ripened seeds imbibed for 6 and 24 h in water and in the transcription inhibitor cordycepin. Transcriptome and translatome changes were investigated. Ribosomal profiles of after-ripened seeds imbibed in cordycepin mimic those of dormant seeds. The polysome occupancy of mRNA species is not affected by germination inhibition, either as a result of seed dormancy or as a result of cordycepin treatment, indicating the importance of the regulation of transcript abundance. The expression of auxin metabolism genes is discriminative during the imbibition of after-ripened and dormant seeds, which is confirmed by altered concentrations of indole-3-acetic acid conjugates and precursors.
Combined transcriptome and translatome analyses reveal a role for tryptophan dependent auxin biosynthesis in the control of DOG1 dependent seed dormancy