Poster: Hormones

Abs # 579: Oligonucleotide array analysis of genes specifically regulated during shoot development in Arabidopsis

Presenter:	Che, Ping , pche@iastate.edu
Authors	Che, Ping  (A)   Lall, Sonia  (A)   Gingerich, Derek J (A)   Howell, Stephen H (A)
Affiliations:	(A): Plant Sciences Institute

We are studying the gene expression programs that underlie shoot development in Arabidopsis tissue culture. Regenerating tissues exposed to different hormone regimes can be directed down different developmental paths toward the formation of shoots, callus or roots. We have identified genes, using Affymetrix Arabidopsis 20K gene chips, that are specifically up- or down-regulated during the formation of shoots (on shoot induction medium, SIM) and not during the formation of callus (on callus induction medium, CIM) or roots (on root induction medium, RIM). From the group of genes specifically up- or downregulated after 3-6 days on SIM (the early SIM regulon), the most highly expressed genes representing transcription factors (TFs) or cytokinin signaling components (CSCs) were chosen for further study. Two upregulated TF or CSC genes in the SIM regulon, CKI1 (Kakimoto, 1996) and ESR1 (Banno et al., 2001), promote shoot formation when induced in the absence of cytokinin. We have also identified common sequence motifs in the promoters of genes in the early SIM regulon and dissected the promoter of one gene in the regulon, ARR5, to find cis-acting regulatory elements that control developmental stage expression.