title: Dynamic aspects of ion accumulation by vesicle traffic under salt stress in Arabidopsis.
abstract: The intracellular membrane dynamics of Arabidopsis cells under high salt treatment were investigated. When Arabidopsis was treated with high levels of NaCl in hydroponic culture, root tip cells showed rapid changes in the vacuolar volume, a decrease in the number of small acid compartments, active movement of vesicles and accumulation of Na(+) both in the central vacuole and in the vesicles around the main vacuole observed with the Na(+)-dependent fluorescence of Sodium Green. Detailed observation of Arabidopsis suspension-cultured cells under high salt treatment showed a similar pattern of response to that observed in root tip cells. Immunostaining of suspension-cultured cells with antibodies against AtNHX1 clearly showed the occurrence of dotted fluorescence in the cytoplasm only under salt treatment. We also confirmed the existence of AtNHX1 in the vacuolar membrane isolated from suspension-cultured cells with immunofluorescence. Knockout of the vacuolar Q(a)-SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein VAM3/SYP22 caused an increase in salt tolerance. In mutant plants, the distribution of Na(+) between roots and shoots differed from that of wild-type plants, with Na(+) accumulating more in roots and less in the shoots of the mutant plants. The role of vesicle traffic under salt stress is discussed.
authors.affiliation: Graduate School of Science, Kobe University, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Hamaji
authors.forename: Megumi
authors.initials: M
authors.lastname: Nagira
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Yoshida
authors.forename: Miwa
authors.initials: M
authors.lastname: Ohnishi
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Oda
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Uemura
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Goh
authors.forename: Masa H
authors.initials: MH
authors.lastname: Sato
authors.forename: Miyo T
authors.initials: MT
authors.lastname: Morita
authors.forename: Masao
authors.initials: M
authors.lastname: Tasaka
authors.forename: Sei-ichiro
authors.initials: S
authors.lastname: Hasezawa
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nakano
authors.forename: Ikuko
authors.initials: I
authors.lastname: Hara-Nishimura
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Maeshima
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Fukaki
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Mimura
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics; D027682:Cation Transport Proteins / Q000235:genetics; D007473:Ion Channels / Q000378:metabolism; D007477:Ions / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000378:metabolism*; D018520:Plant Shoots / Q000378:metabolism; D050765:Qa-SNARE Proteins / Q000235:genetics; D012965:Sodium Chloride / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics; D013312:Stress, Physiological; D014617:Vacuoles / Q000378:metabolism / Q000648:ultrastructure*
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; D007473:Ion Channels; D007477:Ions; C117751:NHX1 protein, Arabidopsis; D050765:Qa-SNARE Proteins; D017923:Sodium-Hydrogen Exchangers; C108430:Vam3 protein, Arabidopsis; D012965:Sodium Chloride