A DREAM of NAC - Molecular mechanism of transcriptional adaptation to DNA stress

点击翻译按钮获取中文摘要

Plants are repeatedly subjected to environmental stresses. A particular harmful condition is acidic soil, prevalent in many regions of the world including most parts of Europe as well as many developing countries. Below a pH of 5.5, Aluminium (Al), the most abundant metal in the crust of the earth, becomes mobile in the form of Al3+ ions and causes phytotoxicity. Previous work of both partners in the frame of an ERA-CAPS project has focused on a recently discovered DNA damaging effect of Al using Arabidopsis and barley, a crop that is highly sensitive to Al, as model plants.In parallel, Arabidopsis mutants have been identified, that show better root growth than the wildtype under mildly DNA damaging conditions, a trait highly relevant to be translated to crops. One of these mutants is defective in a NAC transcription factor, a close homolog of the central DNA damage regulator SOG1. Another one is mutant for the transcription factor MYB3R3, which has been shown to be part of a repressor complex called DREAM. The DREAM complex is key for cell cycle control in animals and is in the focus of current research due to its involvement in cancer. Although components of a DREAM complex have been discovered in Arabidopsis with important roles in development and physiology, knowledge about the plant DREAM complex is in its infancy and even the core composition of the complex is not yet clear. In our preparatory work, we have now discovered a link between the above-mentioned NAC and the DREAM complex. A tandem affinity purification experiment using the central cell cycle regulator RBR1 of Arabidopsis as a bait resulted in the identification of this NAC transcription factor as well as homologs of almost all constituents of the human DREAM complex next to several new components. Following the solid base that was laid in the previous project, both partners want to expand their collaboration now in the frame of the Beethoven Life program and develop a long-term collaboration exploring a novel transcriptional mechanism describing how plants adjust their growth and physiology to genotoxic environmental conditions. The overall aim of this project is not only to obtain fundamental and mechanistic insights into the function of the DREAM complex but also to build a foundation for the subsequent translation of these results, i.e. the generation of Al resistant crops.