Jacobsen S E, Olszewski N E
Department of Plant Biology, University of Minnesota, St. Paul 55108.
Plant Cell. 1993 Aug;5(8):887-96. doi: 10.1105/tpc.5.8.887.
Three independent recessive mutations at the SPINDLY (SPY) locus of Arabidopsis confer resistance to the gibberellin (GA) biosynthesis inhibitor paclobutrazol. Relative to wild type, spy mutants exhibit longer hypocotyls, leaves that are a lighter green color, increased stem elongation, early flowering, parthenocarpy, and partial male sterility. All of these phenotypes are also observed when wild-type Arabidopsis plants are repeatedly treated with gibberellin A3 (GA3). The spy-1 allele is partially epistatic to the ga1-2 mutation, which causes GA deficiency. In addition, the spy-1 mutation can simultaneously suppress the effects of the ga1-2 mutation and paclobutrazol treatment, which inhibit different steps in the GA biosynthesis pathway. This observation suggests that spy-1 activates a basal level of GA signal transduction that is independent of GA. Furthermore, results from GA3 dose-response experiments suggest that GA3 and spy-1 interact in an additive manner. These results are consistent with models in which the SPY gene product regulates a portion of the GA signal transduction pathway.
拟南芥SPINDLY（SPY）基因座上的三个独立隐性突变赋予了对赤霉素（GA）生物合成抑制剂多效唑的抗性。相对于野生型，spy突变体表现出更长的下胚轴、颜色更浅的绿色叶片、茎伸长增加、早花、单性结实和部分雄性不育。当用赤霉素A3（GA3）反复处理野生型拟南芥植株时，也会观察到所有这些表型。spy - 1等位基因对导致GA缺乏的ga1 - 2突变具有部分上位性。此外，spy - 1突变可以同时抑制ga1 - 2突变和多效唑处理的效果，这两种处理分别抑制GA生物合成途径中的不同步骤。这一观察结果表明，spy - 1激活了一个独立于GA的GA信号转导基础水平。此外，GA3剂量反应实验结果表明，GA3和spy - 1以累加方式相互作用。这些结果与SPY基因产物调节部分GA信号转导途径的模型一致。
