Abstract
Cytokinin inhibits root formation and activates shoot formation in tissue culture. This suggests that cyokinins regulate processes that govern root/shoot decision. We analyzed 16 genes that were strongly repressed by cytokinins in the cytokinin hypersensitive mutants, ckh1, and ckh2. We first examined expression patterns of these genes. 6 genes were specifically expressed in the root apex. To understand the functions of these genes, we overexpressed these genes, and found a gene that induced roots on cotyledons when overexpressed. This gene codes for an uncharacterized transcription factor. This gene, when fused to the sequence for SRDX repressor domain, gave shoot properties to the root. These results suggest that this gene potentially confers root identity to stem cells, and prevents the root stem cells from expressing shoot properties.
