title: Reactive oxygen species mediate Na+-induced SOS1 mRNA stability in Arabidopsis.
abstract: Salt Overly Sensitive 1 (SOS1), a plasma membrane Na+/H+ antiporter in Arabidopsis, is a salt tolerance determinant crucial for the maintenance of ion homeostasis in saline stress conditions. SOS1 mRNA is unstable at normal growth conditions, but its stability is substantially increased under salt stress and other ionic and dehydration stresses. In addition, H2O2 treatment increases the stability of SOS1 mRNA. SOS1 mRNA is inherently unstable and rapidly degraded with a half-life of approximately 10 min. Rapid decay of SOS1 mRNA requires new protein synthesis. Stress-induced SOS1 mRNA stability is mediated by reactive oxygen species (ROS). NADPH oxidase is also involved in the upregulation of SOS1 mRNA stability, presumably through the control of extracellular ROS production. The cis-element required for SOS1 mRNA instability resides in the 500-bp region within the 2.2 kb at the 3' end of the SOS1 mRNA. Furthermore, mutations in the SOS1 gene render sos1 mutants more tolerant to paraquat, a non-selective herbicide causing oxidative stress, indicating that SOS1 plays negative roles in tolerance of oxidative stress. A hypothetical model for the signaling pathway involving SOS1-mediated pH changes, NADPH oxidase activation, apoplastic ROS production and downstream signaling transduction is proposed, and the biological significance of ROS-mediated induction of SOS1 mRNA stability is discussed.
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA.
authors.forename: Jung-Sung
authors.initials: JS
authors.lastname: Chung
authors.forename: Jian-Kang
authors.initials: JK
authors.lastname: Zhu
authors.forename: Ray A
authors.initials: RA
authors.lastname: Bressan
authors.forename: Paul M
authors.initials: PM
authors.lastname: Hasegawa
authors.forename: Huazhong
authors.initials: H
authors.lastname: Shi
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins; D015152:Blotting, Northern; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D020871:RNA Stability / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D012965:Sodium Chloride / Q000494:pharmacology*; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D017382:Reactive Oxygen Species; C477653:SOS1 protein, Arabidopsis; D017923:Sodium-Hydrogen Exchangers; D012965:Sodium Chloride; D006861:Hydrogen Peroxide