Osakabe Yuriko, Maruyama Kyonoshin, Seki Motoaki, Satou Masakazu, Shinozaki Kazuo, Yamaguchi-Shinozaki Kazuko
Biological Resources Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan.
Plant Cell. 2005 Apr;17(4):1105-19. doi: 10.1105/tpc.104.027474. Epub 2005 Mar 16.
Abscisic acid (ABA) is important in seed maturation, seed dormancy, stomatal closure, and stress response. Many genes that function in ABA signal transduction pathways have been identified. However, most important signaling molecules involved in the perception of the ABA signal or with ABA receptors have not been identified yet. Receptor-like kinase1 (RPK1), a Leu-rich repeat (LRR) receptor kinase in the plasma membrane, is upregulated by ABA in Arabidopsis thaliana. Here, we show the phenotypes of T-DNA insertion mutants and RPK1-antisense plants. Repression of RPK1 expression in Arabidopsis decreased sensitivity to ABA during germination, growth, and stomatal closure; microarray and RNA gel analysis showed that many ABA-inducible genes are downregulated in these plants. Furthermore, overexpression of the RPK1 LRR domain alone or fused with the Brassinosteroid-insensitive1 kinase domain in plants resulted in phenotypes indicating ABA sensitivity. RPK1 is involved in the main ABA signaling pathway and in early ABA perception in Arabidopsis.
脱落酸(ABA)在种子成熟、种子休眠、气孔关闭及应激反应中发挥着重要作用。许多在ABA信号转导途径中起作用的基因已被识别。然而,参与ABA信号感知或与ABA受体相关的最重要的信号分子尚未被识别。类受体激酶1(RPK1)是一种位于质膜上富含亮氨酸重复序列(LRR)的受体激酶,在拟南芥中受ABA上调。在此,我们展示了T-DNA插入突变体和RPK1反义植株的表型。拟南芥中RPK1表达的抑制降低了种子萌发、生长及气孔关闭过程中对ABA的敏感性;微阵列和RNA凝胶分析表明,许多ABA诱导基因在这些植株中表达下调。此外,单独过表达RPK1的LRR结构域或与油菜素内酯不敏感1激酶结构域融合过表达,在植株中产生了表明对ABA敏感的表型。RPK1参与拟南芥主要的ABA信号途径及早期ABA感知。