Submitted by Helen C. Scott on Wed, 07/02/2018 - 08:34
New work from Julian Hibberd's lab published in the Proceedings of the National Academy of Sciences USA has identified two duons as regulators of photosynthesis gene expression in the C4 plant Gynandropsis gynandra (Reyna-Llorens et al. DOI: ). Duons are so-called because they represent DNA sequence that plays a dual role in coding for amino acids but also in transcription factor binding and thus gene regulation. The work provides functional evidence for two such duons in plants, and shows that in C4 leaves they restrict gene expression to bundle sheath cells (see image). Interestingly, these duons are present in ancestral C3 species of land plants and even some chlorophyte algae. We propose that the prevalence of these motifs in C3 species has likely facilitated the repeated evolution of the complex C4 system.