NMD-Based Gene Regulation-A Strategy for Fitness Enhancement in Plants?

Post-transcriptional RNA quality control is a vital issue for all eukaryotes to secure accurate gene expression, both on a qualitative and quantitative level. Among the different mechanisms, nonsense-mediated mRNA decay (NMD) is an essential surveillance system that triggers degradation of both aberrant and physiological transcripts. By targeting a substantial fraction of all transcripts for degradation, including many alternative splicing variants, NMD has a major impact on shaping transcriptomes. Recent progress on the transcriptome-wide profiling and physiological analyses of NMD-deficient plant mutants revealed crucial roles for NMD in gene regulation and environmental responses. In this review, we will briefly summarize our current knowledge of the recognition and degradation of NMD targets, followed by an account of NMD's regulation and physiological functions. We will specifically discuss plant-specific aspects of RNA quality control and its functional contribution to the fitness and environmental responses of plants.