Abstract
Molecular mechanisms of axillary bud dormancy resulting from apical dominance are still unknown. To analyze the mechanisms controlling dormancy in axillary bud of Arabidopsis, we compared gene expression profile before and after release from bud dormancy. Of the 22,746 genes represented on the Affymetrix ATH1 GenomeArray, expression of the 1,678 genes and 1,188 genes was down- and up-regulated by decapitation, respectively. We identified sugar-repressive element (SRE), which was enriched in the down-regulated genes, and two elements, Up1- and Up2-box, involving in the up-regulation. Both in silico and in vivo analyses demonstrated these elements are the functional components defining gene expression profiles. SRE was involved in the suppression of gene expression by sugar, and mainly regulated the expression of metabolism-related genes in dormant buds. In contrast, Up-boxes were principally related to protein synthesis after release from bud dormancy. We propose mechanisms of growth regulation that govern in axillary bud dormancy.
