Synaptotagmin-Mediated Plasma Membrane Repair in the Regulation of Cold Stress Tolerance

A. ROSADO; A.L. SCHAPIRE; C. PEREA; J. PÉREZ-SANCHO; V. VALPUESTA; J. SALINAS; MA. BOTELLA

Segovia

Congreso; XI Reunión de Biología Molecular de Plantas; 2012

Being one of the first points of contact for environmental adverse conditions, the plasma membrane plays an important role in stress responses. Reflecting this significance, the integrity of this biological barrier has been shown to be protected by a repairing mechanism in which Synaptotagmin 1 (SYT1) has been the first component identified. Here we found that the homologous SYT3 protein participates, along with SYT1, in the maintenance of plasma membrane integrity during osmotic stress and plant fitness during freezing conditions. The SYT3 gene undergoes several alternative splicing in introns 3 and 6, one of the combinations producing the predicted SYT3 functional protein. As SYT1, SYT3 is ubiquitously expressed, is able to bind phospholipids in a calcium dependent manner, and it is induced after cold treatments. Interestingly, while SYT1 is essential for cold tolerance in acclimated and non-acclimated plants, SYT3 is important for tolerance only after plants have been cold-acclimated. Our results point to SYT3 as a cold inducible component of the plasma membrane repair machinery in Arabidopsis required for proper cold acclimation.