title: The RopGEF2-ROP7/ROP2 Pathway Activated by phyB Suppresses Red Light-Induced Stomatal Opening.
abstract: Circadian rhythm of stomatal aperture is mainly regulated by light/darkness. Blue and red light induce stomatal opening through different mechanisms that are mediated by special receptors. ROP2, a member of Rho GTPase family in Arabidopsis (Arabidopsisthaliana), has been found to negatively regulate light-induced stomatal opening. However, the upstream guanine nucleotide exchange factor (GEF) RopGEFs have not been revealed, and it is unclear which photoreceptor is required for the action of RopGEFs-ROPs. Here, we showed that RopGEF2 acted as a negative regulator in phytochrome B (phyB)-mediated red light-induced stomatal opening. Meanwhile, ROP7, another member of ROP family, acting redundantly with ROP2, was regulated by RopGEF2 in this process. RopGEF2 interacted with ROP7 and ROP2 and enhanced their intrinsic nucleotide exchange rates. Furthermore, the direct interactions between phyB and RopGEF2 were detected in vitro and in plants, and phyB enhanced the GEF activity of RopGEF2 toward both ROP7 and ROP2 under light. In addition, RopGEF4 functioned redundantly with RopGEF2 in red light-induced stomatal opening by activating both ROP7 and ROP2, andRopGEF2/RopGEF4acted genetically downstream ofphyB; however, the GEF activity of RopGEF4 was not directly enhanced by phyB. These results revealed that red light-activated phyB enhances the GEF activities of RopGEF2 and RopGEF4 directly or indirectly, and then activate both ROP7 and ROP2 in guard cells. The negative mechanism triggered by phyB prevents the excessive stomatal opening under red light.
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Zhao
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Bao
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Sha-Sha
authors.initials: SS
authors.lastname: Zhang
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Chun-Guang
authors.identifier: http://orcid.org/0000-0003-4287-9183
authors.initials: CG
authors.lastname: Zhang
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Hai-Xia
authors.initials: HX
authors.lastname: Li
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Xiao-Lu
authors.identifier: http://orcid.org/0000-0001-7956-8878
authors.initials: XL
authors.lastname: Zhang
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Atle Magnar
authors.initials: AM
authors.lastname: Bones
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.).|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.).
authors.forename: Zhen-Biao
authors.initials: ZB
authors.lastname: Yang
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China (W.W., Z.L., L.-J.B., S.-S.Z., C.-G.Z., X.L., H.-X.L., X.-L.Z., Y.-L.C.); yulingchen@hebtu.edu.cn.|Center for Plant Cell Biology, Department of Botany and Sciences, University of California, Riverside, California 92521 (Z.-B.Y.); and yulingchen@hebtu.edu.cn.|Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway (A.M.B.) yulingchen@hebtu.edu.cn.
authors.forename: Yu-Ling
authors.identifier: http://orcid.org/0000-0001-5110-1096
authors.initials: YL
authors.lastname: Chen
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D008027:Light; D053858:Metabolic Networks and Pathways; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D051939:Phytochrome B / Q000235:genetics / Q000378:metabolism*; D054046:Plant Stomata / Q000502:physiology*; D030821:Plants, Genetically Modified; D021381:Protein Transport
chemical_list: D029681:Arabidopsis Proteins; D019204:GTP-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D020559:Monomeric GTP-Binding Proteins; D051939:Phytochrome B; C497952:PHYB protein, Arabidopsis; C572956:ROPGEF4 protein, Arabidopsis; C000612241:RopGEF2 protein, Arabidopsis; C499714:AT1G20090 protein, Arabidopsis; C505651:RAC2 protein, Arabidopsis