An objective of the present invention is to provide gibberellin-binding proteins, genes encoding such proteins, and applications therefor. The proteins of the present invention function as cytoplasmic receptors for gibberellin and mediate gibberellin response in plants. Plants overexpressing such genes exhibited gibberellin-hypersensitive phenotypes, such as increased plant height. In contrast, plants in which the genes were mutated exhibited gibberellin-insensitive phenotypes, and thus became dwarfed. Accordingly, plant differentiation and growth can be regulated by introducing the gibberellin-binding genes of the present invention or by suppressing the expression of same.