Evolution and regulation of SNF1/AMPK/SnRK1 and trehalose 6-phosphate in eukaryotes: questions and lessons on energy signalling in plants

Sugar signalling in plants is crucial to distribute available energy and respond appropriately to energy deprivation induced by nutrient shortage or environmental and biotic stresses. Several regulatory systems are involved in sugar signalling in plants. Orthologs of components of these systems are often already studied in non-plant eukaryotes. Knowledge about the function of these orthologous systems can contribute to unravelling sugar signalling pathways in plants. Differences between sugar signalling in different species might increase our understanding of the way in which evolution dealt with characteristics of these species that influence their regulation of metabolism. In order to better understand the function and evolutionary history of two sugar signalling components in plants, the SnRK1 kinase complex and trehalose 6-phosphate, their regulation and downstream effects were compared between plants, yeast and mammals. Current knowledge on the evolution of these systems was also collected. Together these data point out interesting directions for future research on sugar signalling in plants and its evolution.