Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/27/2006
Publication Date: 8/7/2006
Citation: Liu, J., Ramirez, M., Hernandez, G., Lara, M., Vance, C.P. 2006. Characterization of WRKY transcription factors expressed in model legumes under phosphorus deficiency [abstract]. American Society of Plant Biologists Annual Meeting. Abstract No. P12013. Interpretive Summary:
Technical Abstract: The WRKY transcription factors (TF) are encoded by a super family of genes specific to plants. Although the function of most WRKY TFs remains to be elucidated, a few have been well characterized based on their specific binding ability to W-box, with the consensus sequence (C/T)TGAC(C/T). These WRKY genes play a crucial role in the regulation of target genes in various processes, including both biotic and abiotic stress. The nuclear localization of WRKY proteins is also consistent with their function as transcriptional regulators. By applying a functional genomics approach we have investigated plant response to phosphorus (P) deficiency in model legume species, including white lupin (Lupinus albus), common bean (Phaseolus vulgaris), and Medicago truncatula. We analyzed a large number of ESTs to identify transcription factor genes which are differentially expressed in response to changing P status. A group of WRKY genes were chosen for further studies because they were found to be either highly up-regulated or down-regulated under P deficiency in the root. RNA gel blot hybridization further indicated that despite the high degree of sequence homology (>70%) among the analyzed WRKY genes, their expression patterns differ significantly. These diverse expression patterns may reflect the fact that WRKY TFs are known to function as both transcriptional activators and repressors and their binding sites may vary from the W-box. Given the complexity of the WRKY superfamily in legumes, phylogenetic analysis of more WRKY genes would facilitate the identification of putative WRKY orthologues in other crop legumes with a conserved function in response to P stress.