RRC ID 4035
Author Yamazaki T, Kawamura Y, Minami A, Uemura M.
Title Calcium-dependent freezing tolerance in Arabidopsis involves membrane resealing via synaptotagmin SYT1.
Journal Plant Cell
Abstract Plant freezing tolerance involves the prevention of lethal freeze-induced damage to the plasma membrane. We hypothesized that plant freezing tolerance involves membrane resealing, which, in animal cells, is accomplished by calcium-dependent exocytosis following mechanical disruption of the plasma membrane. In Arabidopsis thaliana protoplasts, extracellular calcium enhanced not only freezing tolerance but also tolerance to electroporation, which typically punctures the plasma membrane. However, calcium did not enhance survival when protoplasts were exposed to osmotic stress that mimicked freeze-induced dehydration. Calcium-dependent freezing tolerance was also detected with leaf sections in which ice crystals intruded into tissues. Interestingly, calcium-dependent freezing tolerance was inhibited by extracellular addition of an antibody against the cytosolic region of SYT1, a homolog of synaptotagmin known to be a calcium sensor that initiates exocytosis. This inhibition indicates that the puncture allowing the antibody to flow into the cytoplasm occurs during freeze/thawing. Thus, we propose that calcium-dependent freezing tolerance results from resealing of the punctured site. Protoplasts or leaf sections isolated from Arabidopsis SYT1-RNA interference (RNAi) plants lost calcium-dependent freezing tolerance, and intact SYT1-RNAi plants had lower freezing tolerance than control plants. Taken together, these findings suggest that calcium-dependent freezing tolerance results from membrane resealing and that this mechanism involves SYT1 function.
Volume 20(12)
Pages 3389-404
Published 2008-12
DOI 10.1105/tpc.108.062679
PII tpc.108.062679
PMID 19088330
PMC PMC2630449
MeSH Arabidopsis / genetics Arabidopsis / metabolism* Arabidopsis / physiology* Arabidopsis Proteins / genetics Arabidopsis Proteins / physiology* Calcium / metabolism* Freezing* Immunoblotting Models, Biological Models, Genetic Molecular Sequence Data Plant Leaves / genetics Plant Leaves / metabolism Plant Leaves / physiology Plants, Genetically Modified / genetics Plants, Genetically Modified / metabolism Plants, Genetically Modified / physiology Protoplasts / metabolism Protoplasts / physiology RNA Interference / physiology Synaptotagmin I / genetics Synaptotagmin I / physiology*
IF 8.631
Times Cited 63
Arabidopsis / Cultured plant cells, genes pda01369