title: The polyamine spermine protects against high salt stress in Arabidopsis thaliana.
abstract: It is well known that changes in abiotic conditions such as the concentration of ions, temperature and humidity lead to modulation of polyamine contents in plants. However, little is known about the relevant parts these polyamines play in abiotic stress responses. Here we addressed a specific role of spermine during high salt stress using an Arabidopsis double knockout-mutant plant (acl5/spms) which cannot produce spermine. The mutant showed higher sensitivity to high salt than wild type plants. This phenotype was cured by exogenous spermine but not by the other polyamines putrescine and spermidine, suggesting a strong link between spermine-deficiency and NaCl-hypersensitivity. The mutant was also hypersensitive to high levels of KCl but not to MgCl(2) or to high osmoticum. NaCl-hypersensitivity of the mutant was compromised by treatment with Ca(2+) channel blockers. Moreover, the mutant showed poor growth on Ca(2+)-depleted Murashige-Skoog agar media. The data suggest that the absence of spermine causes an imbalance in Ca(2+) homeostasis in the mutant plant. Based on the data obtained, we propose a model for a role of spermine in high salt stress responses.
authors.affiliation: Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Thomas
authors.initials: T
authors.lastname: Berberich
authors.forename: Akihiko
authors.initials: A
authors.lastname: Imai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Miyazaki
authors.forename: Taku
authors.initials: T
authors.lastname: Takahashi
authors.forename: Anthony
authors.initials: A
authors.lastname: Michael
authors.forename: Tomonobu
authors.initials: T
authors.lastname: Kusano
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D030821:Plants, Genetically Modified; D012492:Salts / Q000494:pharmacology*; D036226:Seedlings / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013096:Spermine / Q000378:metabolism* / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; D012492:Salts; D013096:Spermine; D002118:Calcium