Modification of rice plant height by suppressing the height-controlling gene, D18, in rice
Modification of rice plant height by suppressing the height-controlling gene, D18, in rice
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DOI：
10.1270/jsbbs.52.215
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发表时间：
2002-09-01
期刊：
影响因子：
2.4
通讯作者：
Matsuoka, M
中科院分区：
文献类型：
--
作者：
Itoh, H;Ueguchi-Tanaka, M;Matsuoka, M
赤霉素(GA)3β-羟基酶催化植物中GA活性合成的最后一步。在水稻中，该酶至少由两个不同表达模式的基因(OsGA3ox1和OsGA3ox2)编码。此前，我们报道了OsGA3ox2基因与D18基因相同。D18的功能丧失突变体D18-AD(Akibaar Waisei)、D18-Id18(H)(Hoetsu Waisei)和D18-dy(Waito-C)表现出由于活性GA、GA(1)水平下降而导致的严重矮化。该基因编码GA 3β-羟基酶，催化从GA(20)到GA(1)的反应，其表达也受到活性GA的反馈机制的调节，提示该酶催化的步骤可能是调节活性GA水平的关键步骤。为了确定通过调节活性GA水平来降低水稻株高的可能性，我们获得了表达反义D18基因的转基因水稻植株。与仅携带反义载体的对照相比，表达反义基因的植株表现出半矮化表型。具有半矮秆表型的反义植株的D18基因表达水平降低。与D18mRNA表达水平降低相反，植株诱导了较高水平的OsGA20ox1的表达，OsGA20ox1编码GA 20-氧化酶，催化GA生物合成途径中从GA(53)到GA(20)的步骤。这些结果表明，水稻株高可以通过降低GA活性水平来调控GA3β-羟基酶的表达。
Gibberellin (GA) 3beta-hydroxylase catalyzes the final step of active GA synthesis in plants. In rice, the enzyme is encoded by at least two genes (OsGA3ox1 and OsGA3ox2) with differential patterns of expression. Previously, we reported that the OsGA3ox2 gene is identical with the D18 gene. The loss-of-function mutants of D18 designated as d18-AD (Akibare waisei), d18-Id18(h) (housetsu waisei), and d18-dy (Waito-C) show severe dwarfism caused by the decrease of the level of active GA, GA(1). The gene encodes GA 3beta-hydroxylase that catalyzes the reaction from GA(20) to GA(1) and its expression is also regulated by active GA through a feedback mechanism, suggesting that the step catalyzed by the enzyme may be a key step for regulating the level of active GA. To determine the possibility of reducing the height of rice through regulation of the level of active GA, we produced transgenic rice plants expressing the antisense of D18 cDNA. Plants expressing the antisense showed a semi-dwarf phenotype relative to the control plants carrying the vector only. The antisense plants with the semi-dwarf phenotype showed a reduced level of D18 mRNA. In contrast to the reduced level of D18 mRNA, the plants induced a higher expression level of OsGA20ox1, which encodes GA 20-oxidase catalyzing the step from GA(53) to GA(20) in the GA biosynthetic pathway. These results demonstrate that the height of rice can be controlled by manipulation of the GA 3beta-hydroxylase expression through the decrease in the active GA level.