Analysis of Spatio-temporal Gene Expression and Involvement of Phytohormone Signaling during Tissue-reunion Process of Arabidopsis Cut Flowering Stem

Abstract

Previously, we analyzed differential gene expression between cut and non-cut flowering stems and their changes in expression during reunion process. Genes that were up-regulated during the reunion process include those involved in cell division, cell wall modification, phytohormone-related gene and transcription factors (TFs). To gain a better understanding of the regulation of large groups of genes on reunion process, we particularly focused on the expression of ERF/AP2- and NAC-type TFs that are specifically up-regulated at earlier stage. Gene expression analysis showed that IAA application down-regulated the level of the expression of AP2-TF and up-regulated that of NAC-TF. Spatio-temporal gene expression analysis revealed that AP2- and NAC-type TF transcripts were specifically induced in lower and upper regions of cut position, respectively. The transformants expressing dominant negative form of AP2-TF and NAC-TF using CRES-T showed abnormal reunion process. These results suggest that phyotohormone signaling pathways and putative downstream TFs have an important role in the regulation of gene expression during tissue-reunion of Arabidopsis cut flowering stems.