Similarity and distinction between organ-specific gibberellin-modulated genome expression between Arabidopsis and rice

Gibberellins (GAs) regulate plant growth and development, at least in part, by modulating downstream gene expression. Different plant species and plant organs are differentially responsive to GAs, though it remains unclear whether there exist organ and species specificities of GA responses at the genome expression level. Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) are model dicot and monocot plants. Microarray analyses indicate that in different organs of both species, small portions of the genomes are affected by GA3 or paclobutrazol (PAC), a gibberellin biosynthetic inhibitor. Gene Ontology analyses reveal that GA3 regulates genes in almost all major functional categories of both species. Functional categorization of GA3-responsive homologous genes suggests that some features of GA3 regulation of genome expression are conserved between the two species. Venn diagrams and cluster display analyses show that only a small gene portion is shared between each pair of rice and Arabidopsis organs, strongly supporting the presence of organ specificity of GA3-regulated gene expression in both species.

► In rice and Arabidopsis, small portions of the genomes are affected by GA or PAC.
► GA regulates genes in almost all major functional categories of both species.
► Some features of GA regulation of gene expression are conserved between two species.
► Organ specificity of GA-regulated gene expression occurs in both species.