title: Release of SOS2 kinase from sequestration with GIGANTEA determines salt tolerance in Arabidopsis.
abstract: Environmental challenges to plants typically entail retardation of vegetative growth and delay or cessation of flowering. Here we report a link between the flowering time regulator, GIGANTEA (GI), and adaptation to salt stress that is mechanistically based on GI degradation under saline conditions, thus retarding flowering. GI, a switch in photoperiodicity and circadian clock control, and the SNF1-related protein kinase SOS2 functionally interact. In the absence of stress, the GI:SOS2 complex prevents SOS2-based activation of SOS1, the major plant Na(+)/H(+)-antiporter mediating adaptation to salinity. GI overexpressing, rapidly flowering, plants show enhanced salt sensitivity, whereas gi mutants exhibit enhanced salt tolerance and delayed flowering. Salt-induced degradation of GI confers salt tolerance by the release of the SOS2 kinase. The GI-SOS2 interaction introduces a higher order regulatory circuit that can explain in molecular terms, the long observed connection between floral transition and adaptive environmental stress tolerance in Arabidopsis.
authors: Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Graduate School of Gyeongsang National University, Jinju 660-701, South Korea.
authors: Woe-Yeon
authors: WY
authors: Kim
authors: Zahir
authors: Z
authors: Ali
authors: Hee Jin
authors: HJ
authors: Park
authors: Su Jung
authors: SJ
authors: Park
authors: Joon-Yung
authors: JY
authors: Cha
authors: Javier
authors: J
authors: Perez-Hormaeche
authors: Francisco Javier
authors: FJ
authors: Quintero
authors: Gilok
authors: G
authors: Shin
authors: Mi Ri
authors: MR
authors: Kim
authors: Zhang
authors: Z
authors: Qiang
authors: Li
authors: L
authors: Ning
authors: Hyeong Cheol
authors: HC
authors: Park
authors: Sang Yeol
authors: SY
authors: Lee
authors: Ray A
authors: RA
authors: Bressan
authors: Jose M
authors: JM
authors: Pardo
authors: Hans J
authors: HJ
authors: Bohnert
authors: Dae-Jin
authors: DJ
authors: Yun
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D035264:Flowers / Q000502:physiology; D008954:Models, Biological; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D055550:Protein Stability / Q000187:drug effects; D059748:Proteolysis / Q000187:drug effects; D055049:Salt Tolerance / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins; C121183:GI protein, Arabidopsis; C477653:SOS1 protein, Arabidopsis; C112941:SOS3 protein, Arabidopsis; D017923:Sodium-Hydrogen Exchangers; D012965:Sodium Chloride; C406738:SOS2 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases