Dynamic aspects of ion accumulation by vesicle traffic under salt stress in Arabidopsis.
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.
Hamaji
Kohei
K
Graduate School of Science, Kobe University, Nada-ku, Kobe, 657-8501, Japan.
Nagira
Megumi
M
Yoshida
Katsuhisa
K
Ohnishi
Miwa
M
Oda
Yoshihisa
Y
Uemura
Tomohiro
T
Goh
Tatsuaki
T
Sato
Masa H
MH
Morita
Miyo T
MT
Tasaka
Masao
M
Hasezawa
Sei-ichiro
S
Nakano
Akihiko
A
Hara-Nishimura
Ikuko
I
Maeshima
Masayoshi
M
Fukaki
Hidehiro
H
Mimura
Tetsuro
T
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*
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