REVIEW ARTICLE AP2/EREBP transcription factors are part of gene regulatory networks and integrate metabolic, hormonal and environmental signals in stress acclimation and retrograde signalling Karl-Josef Dietz & Marc Oliver Vogel & Andrea Viehhauser Received: 1 February 2010 / Accepted: 1 April 2010 / Published online: 22 April 2010 # Springer-Verlag 2010 Abstract To optimize acclimation responses to environ- mental growth conditions, plants integrate and weigh a diversity of input signals. Signal integration within the signalling networks occurs at different sites including the level of transcription factor activation. Accumulating evidence assigns a major and diversified role in environ- mental signal integration to the family of APETALA 2/ ethylene response element binding protein (AP2/EREBP) transcription factors. Presently, the Plant Transcription Factor Database 3.0 assigns 147 gene loci to this family in Arabidopsis thaliana, 200 in Populus trichocarpa and 163 in Oryza sativa subsp. japonica as compared to 13 to 14 in unicellular algae (http://plntfdb.bio.uni-potsdam.de/ v3.0/). AP2/EREBP transcription factors have been impli- cated in hormone, sugar and redox signalling in context of abiotic stresses such as cold and drought. This review exemplarily addresses present-day knowledge of selected AP2/EREBP with focus on a function in stress signal integration and retrograde signalling and defines AP2/ EREBP-linked gene networks from transcriptional profiling-based graphical Gaussian models. The latter approach suggests highly interlinked functions of AP2/ EREBPs in retrograde and stress signalling. Keywords AP2/EREBP . Gaussian models . Transcription factors . Hormone . Redox . Retrograde signalling . Abiotic stress Abbreviations ABA abscisic acid AP2 APETALA 2 DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea CBF C-repeat binding factor DREB dehydration-responsive element binding protein EREBP ethylene response element binding protein ERF ethylene responsive factor GGM graphical Gaussian model PSY phytoene synthase RAP2 related to AP2 RAV related to ABI3/VP1 TF transcription factor The AP2/EREBP gene family in plants Among the more than 1,600 transcription factors (TFs) encoded by the Arabidopsis thaliana genome, the family of APETALA 2/ethylene responsive element binding protein (AP2/EREBP)-like proteins comprises a major fraction with a share of about 9%. Thus, the genome-wide search by Feng et al. (2005) identified 147 AP2/EREBPs. The Plant Transcription Factor Database 3.0 (Riano-Pachon et al. 2007), a public database aimed at identifying and catalogu- ing all plant genes involved in transcriptional control, assigns also 147 genes to this family. In higher plants, between 124 (Vitis vinifera) and 200 (Populus trichocarpa) loci are reported to belong to the AP2/EREBP family (Table 1). In unicellular green algae, the low number of 13 This article is published as part of the Special Issue on Stress metabolism of plant Electronic supplementary material The online version of this article (doi:10.1007/s00709-010-0142-8) contains supplementary material, which is available to authorized users. K.-J. Dietz (*) : M. O. Vogel : A. Viehhauser Biochemistry and Physiology of Plants–W5, Bielefeld University, 33501 Bielefeld, Germany e-mail: karl-josef.dietz@uni-bielefeld.de Protoplasma (2010) 245:3–14 DOI 10.1007/s00709-010-0142-8