GSE26722
Role of class III HD-ZIP transcription factors in shade signaling
Unlike the situation in animals, the final morphology of the plant body is highly modulated by the environment. During Arabidopsis development, intrinsic factors provide the framework for basic patterning processes. CLASS III HOMEODOMAIN LEUCINE ZIPPER (HD-ZIPIII) transcription factors are involved in embryo, shoot and root patterning and during vegetative growth regulate several polarity set-up processes such as in leaves and the vascular system. Here we show that besides being involved in basic patterning, HD-ZIPIII transcription factors also have a critical role in controlling elongation growth that is induced when plants experience shade. By using a ChIP-Seq approach, we have identified several direct target genes of the HD-ZIPIII transcription factor REVOLUTA (REV). We show that REV acts upstream of auxin biosynthesis and directly regulates several HAT transcription factors that control shade avoidance responses in Arabidopsis. Plants in which HD-ZIPIII genes are mutated show altered responses to shade revealing that the basic patterning machinery also regulates adaptive development. Thus, HD-ZIPIII transcription factors contribute to shade signaling and act upstream of both auxin and HAT activation. Overall design: A. thaliana REVOLUTA ChIP-seq w control