PROBLEM TO BE SOLVED: To provide an agent for controlling growth or differentiation of plants and to provide a technique for searching a chemical substance having useful biological activity clarifying a target, namely a method, etc., for screening the chemical substance with activity to a specific target in order to chemically control the target part.SOLUTION: The method for searching for a chemical substance promoting the growth of a root of a plant comprises measuring the level of intracellular signaling from a cytokinin receptor in a system where a cell having the cytokinin receptor derived from a plant is brought into contact with a chemical substance having an agonistic activity on the receptor and a substance to be tested, comparing the level of intracellular signaling measured in the preceding step with a level of intracellular signaling measured in the absence of the chemical substance and determining the chemical substance as being a chemical substance promoting the growth of a root of a plant based on the difference obtained by the comparison. 6-Chloro-2-ethoxycarbonylmethylamino-4-phenylquinazoline, etc., was found as the active substance by the method.COPYRIGHT: (C)2008,JPO&INPIT【課題】植物の生長若しくは分化を制御する薬剤、並びに、標的を明確にした有用な生物活性を有する化学物質の探索手法、即ち、標的部位を化学的に調節する、特定の標的に対する活性で化学物質をスクリーニングする方法等を提供する。【解決手段】植物由来のサイトカイニン受容体を有する細胞と前記受容体に対してアゴニスト活性を有する物質と被験物質との接触系内において、前記受容体からの細胞内信号伝達の量を測定し、次いで測定された量と前記化学物質が存在しない場合における細胞内信号伝達の量とを比較することにより得られる差異に基づき植物の根の生長促進能力を有する化学物質。この方法により、活性物質として、6-クロロ-2-エトキシカルボニルメチルアミノ-4-フェニルキナゾリン等を見いだした。【選択図】なし
