ORIGINAL PAPER Members of the Dof transcription factor family in Triticum aestivum are associated with light-mediated gene regulation Lindsay M. Shaw & C. Lynne McIntyre & Peter M. Gresshoff & Gang-Ping Xue Received: 12 March 2009 / Revised: 9 June 2009 / Accepted: 23 June 2009 / Published online: 4 July 2009 # Springer-Verlag 2009 Abstract DNA binding with One Finger (Dof) protein is a plant-specific transcription factor implicated in the regula- tion of many important plant-specific processes, including photosynthesis and carbohydrate metabolism. This study has identified 31 Dof genes (TaDof) in bread wheat through extensive analysis of current nucleotide databases. Phylo- genetic analysis suggests that the TaDof family can be divided into four clades. Expression analysis of the TaDof family across all major organs using quantitative RT-PCR and searches of the wheat genome array database revealed that the majority of TaDof members were predominately expressed in vegetative organs. A large number of TaDof members were down-regulated by drought and/or were responsive to the light and dark cycle. Further expression analysis revealed that light up-regulated TaDof members were highly correlated in expression with a number of genes that are involved in photosynthesis or sucrose transport. These data suggest that the TaDof family may have an important role in light-mediated gene regulation, including involvement in the photosynthetic process. Keywords Transcription factor . Triticum aestivum . Dof . Gene expression profiling . Phylogenetic analysis Introduction Bread wheat (Triticum aestivum) is one of the world’ s most important food crops. However, significant increases in productivity are necessary to keep up with growing global demand. One approach to achieving this aim is to focus on key regulators of wheat growth and development. Tran- scription factors (TFs) are an important group of regulatory genes and regulate transcription through a two-step process, binding to a specific DNA sequence and subsequent transcriptional activation or repression (Wray et al. 2003). They are involved in the control of all biological processes in plants such as photosynthesis, growth, development and the regulation of gene response to developmental and environmental changes (Meshi and Iwabuchi 1995). Plants possess a number of plant-specific TF families, some of which regulate these plant-specific biological processes. One such family is the DNA binding with One Finger (Dof) family of TFs (Yanagisawa 2004). Dof proteins have been shown to play critical roles as transcriptional regulators in many plant-specific biological processes related to plant photosynthesis, growth and devel- opment (Yanagisawa and Sheen 1998; Yanagisawa 2000, 2002, 2004; Gualberti et al. 2002; Park et al. 2003; Yanagisawa et al. 2004; Ward et al. 2005; Imaizumi et al. 2005; Imaizumi and Kay 2006; Skirycz et al. 2008). Dof proteins are also present in unicellular, green algae, but not in non-photosynthetic organisms (Moreno-Risueno et al. 2007; Riaño-Pachón et al. 2008), suggesting a potential role in regulating the photosynthesis process. From the model species for dicotyledonous and monocotyledonous plant species, bioinformatics analysis has identified 36 Dof gene loci (44 gene models) in Arabidopsis and 30 loci (36 gene models) in rice (Lijavetzky et al. 2003; http://plntfdb.bio.uni- potsdam.de/v2.0/), several of which have been characterised. Electronic supplementary material The online version of this article (doi:10.1007/s10142-009-0130-2) contains supplementary material, which is available to authorized users. L. M. Shaw : C. L. McIntyre : G.-P. Xue (*) CSIRO Plant Industry, 306 Carmody Rd, St Lucia, QLD 4067, Australia e-mail: gang-ping.xue@csiro.au L. M. Shaw : P. M. Gresshoff ARC Centre of Excellence for Integrative Legume Research, The University of Queensland, St Lucia, QLD 4072, Australia Funct Integr Genomics (2009) 9:485–498 DOI 10.1007/s10142-009-0130-2