The phytohormone abscisic acid （ABA） regulates many key processes in plants, such as seed germina- tion, seedling growth, and abiotic stress tolerance. In recent years, a minimal set of core components of a major AB...The phytohormone abscisic acid （ABA） regulates many key processes in plants, such as seed germina- tion, seedling growth, and abiotic stress tolerance. In recent years, a minimal set of core components of a major ABA signaling pathway has been discovered. These components include a RCAR/PYR/PYL family of ABA receptors, a group of PP2C phosphatases, and three SnRK2 kinases. However, how the interactions between the receptors and their targets are regulated by other proteins remains largely unknown. In a companion paper published in this issue, we showed that ROP11, a member of the plant- specific Rho-like small GTPase family, negatively regulates multiple ABA responses in Arabidopsis. The current work demonstrated that the constitutively active ROP11 （CA-ROP11） can modulate the RCAR1/PYL9-mediated ABA signaling pathway based on reconstitution assays in Arabidopsis thaliana protoplasts. Furthermore, using luciferase complementation imaging, yeast two-hybrid assays, co- immunoprecipitation assays in Nicotiana benthamiana and bimolecular fluorescence complementation assays, we demonstrated that CA-ROP11 directly interacts with ABI1, a signaling component downstream of RCAR1/PYL9. Finally, we provided biochemical evidence that CA-ROP11 protects ABI1 phosphatase activity from inhibition by RCAR1/PYL9 and thus negatively regulates ABA signaling in plant cells. A model of how ROP11 acts to negatively regulate ABA signaling is presented.展开更多
植物激素脱落酸(ABA)参与从种子萌发到植物开花、结果和衰老等多个生长发育过程。研究ABA细胞信号转导的分子机制对进一步阐明其功能具有重要的意义。通过介绍FCA(Flowering Control Locus A)、Mg离子螯合酶H亚基(ABAR/CHLH)、G蛋白偶...植物激素脱落酸(ABA)参与从种子萌发到植物开花、结果和衰老等多个生长发育过程。研究ABA细胞信号转导的分子机制对进一步阐明其功能具有重要的意义。通过介绍FCA(Flowering Control Locus A)、Mg离子螯合酶H亚基(ABAR/CHLH)、G蛋白偶联受体(GCR2)、GTG1/GTG2(GPCR-type G-Proteins1/2)和PYR1/PYL/RCAR在ABA信号传导途径中的作用模式,阐述了其能够接受ABA信号并激活相关下游组分,从而完成其生理功能。展开更多
基金supported by the 973National Basic Research Program of the Ministry of Science and Technology of China(2009CB119100)the National Natural Science Foundation of China(90717121)
文摘The phytohormone abscisic acid （ABA） regulates many key processes in plants, such as seed germina- tion, seedling growth, and abiotic stress tolerance. In recent years, a minimal set of core components of a major ABA signaling pathway has been discovered. These components include a RCAR/PYR/PYL family of ABA receptors, a group of PP2C phosphatases, and three SnRK2 kinases. However, how the interactions between the receptors and their targets are regulated by other proteins remains largely unknown. In a companion paper published in this issue, we showed that ROP11, a member of the plant- specific Rho-like small GTPase family, negatively regulates multiple ABA responses in Arabidopsis. The current work demonstrated that the constitutively active ROP11 （CA-ROP11） can modulate the RCAR1/PYL9-mediated ABA signaling pathway based on reconstitution assays in Arabidopsis thaliana protoplasts. Furthermore, using luciferase complementation imaging, yeast two-hybrid assays, co- immunoprecipitation assays in Nicotiana benthamiana and bimolecular fluorescence complementation assays, we demonstrated that CA-ROP11 directly interacts with ABI1, a signaling component downstream of RCAR1/PYL9. Finally, we provided biochemical evidence that CA-ROP11 protects ABI1 phosphatase activity from inhibition by RCAR1/PYL9 and thus negatively regulates ABA signaling in plant cells. A model of how ROP11 acts to negatively regulate ABA signaling is presented.
文摘植物激素脱落酸(ABA)参与从种子萌发到植物开花、结果和衰老等多个生长发育过程。研究ABA细胞信号转导的分子机制对进一步阐明其功能具有重要的意义。通过介绍FCA(Flowering Control Locus A)、Mg离子螯合酶H亚基(ABAR/CHLH)、G蛋白偶联受体(GCR2)、GTG1/GTG2(GPCR-type G-Proteins1/2)和PYR1/PYL/RCAR在ABA信号传导途径中的作用模式,阐述了其能够接受ABA信号并激活相关下游组分,从而完成其生理功能。
