Casting Away the Shadows: Elucidating the Role of Light-mediated Posttranscriptional Control in Plants

Light signals trigger precise changes in gene expression networks that activate distinctive developmental programs in plants. The transcriptome is shaped at different stages, both by the regulation of gene expression and also by posttranscriptional mechanisms that alter the sequence or abundance of the transcripts generated. Posttranscriptional mechanisms have attracted much interest in recent years with the advent of high-throughput technologies and bioinformatics tools. One such posttranscriptional process, alternative splicing, increases proteome diversity without increasing gene number by changing the function of individual proteins, while another, miRNA-mediated gene silencing, fine-tunes the amount of mRNA produced. The manner in which plants make use of these two crucial posttranscriptional mechanisms to respond to light and adapt to their environment is the focus of active research. In this review, we summarize the current knowledge of light-mediated posttranscriptional control in Arabidopsis thaliana and focus on the biological impact of the various posttranscriptional processes. We also discuss a potential cross talk between the alternative splicing and miRNA pathways, highlighting the complexity of light responsiveness.