The lipidome remodeling during cold acclimation is an important evolutionary
milestone to plant adaption to sub-optimal temperature conditions. In Arabidopsis, the
phospholipid binding protein Synaptotagmin1 (SYT1) maintains the plasma membrane
(PM) integrity during abiotic stress (1, 2) , participates in the Ca2+-dependent acquisition of
freezing tolerance (3), and it is involved in viral protein cell-to-cell movement (4). Despite
these important roles, its PM delivery mechanisms, lipid membrane targets, and in vivo
effects on lipid composition have been largely overlooked. In this report (5), we establish
that SYT1 is an ER and PM associated protein that specifically binds negatively charged
phosphoinositides and glycerolipids, and its loss causes the over-accumulation of its
phospholipid binding partners in vivo. We also present a preliminary characterization of
SYT3, an additional phospholipid binding member of the Arabidopsis SYT family, as a
unique stress inducible determinant required for lipidome remodeling during cold stress
episodes.
