Transcript profiling of auxin/cytokinin crosstalk in the Arabidopsis primary root apex

AtIPT8/pga22 seedlings (gain-of-function mutant in Ws background; Sun et al. 2003, Plant Physiology 131, pp167-176) were grown on vertical plates for 7 days in LD. The seedlings were then incubated directly on the plate with medium containing 5 uM 17-beta-estradiol (for induction of the IPT8 gene) or 5 uM trans-zeatin for 12 and 24 h. 5 mm primary root tips were harvested from the seedlings and pooled for microarray analysis. Total RNA was isolated from the samples with the RNeasy Plant Mini Kit from Qiagen. 14 samples were used in this experiment.