Preferential ribosome loading on the stress-responsive mRNA pool shapes the translation profile under different stress conditions

Reprogramming of gene expression is one of the key responses to environmental stimuli, whereas changes in mRNA do not necessarily bring forth corresponding changes of the protein. We investigated the coordination and discordance between transcription and translation under different stresses in Arabidopsis and found that a substantial fraction of total mRNAs were present in the polysomes, however, to a large extent, the mRNAs were not evenly loaded with ribosomes. Notably, typical stress responsive genes were coordinately regulated at both transcriptional and translational levels, while stress irrelevant genes were changed solely at a single level, suggesting that stress-specific ribosome loading onto the existing mRNAs pool could be a pacing factor for preferential translation.