Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
Johannes Hanson
Department of Molecular Plant Physiology, Utrecht University, Utrecht, Netherlands; Department of Plant Physiology, Umea Plant Science Center, Umeå University, Umea, Sweden
Elena Baena-González
Instituto Gulbenkian de Ciência, Oeiras, Portugal
Christina Chaban
Department of Plant Physiology, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
Wolfram Weckwerth
Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
Wolfgang Dröge-Laser
Pharmaceutical Biology, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
Metabolic adjustment to changing environmental conditions, particularly balancing of growth and defense responses, is crucial for all organisms to survive. The evolutionary conserved AMPK/Snf1/SnRK1 kinases are well-known metabolic master regulators in the low-energy response in animals, yeast and plants. They act at two different levels: by modulating the activity of key metabolic enzymes, and by massive transcriptional reprogramming. While the first part is well established, the latter function is only partially understood in animals and not at all in plants. Here we identified the Arabidopsis transcription factor bZIP63 as key regulator of the starvation response and direct target of the SnRK1 kinase. Phosphorylation of bZIP63 by SnRK1 changed its dimerization preference, thereby affecting target gene expression and ultimately primary metabolism. A bzip63 knock-out mutant exhibited starvation-related phenotypes, which could be functionally complemented by wild type bZIP63, but not by a version harboring point mutations in the identified SnRK1 target sites.
