Abstract
Parenchyma cells of xylem (XPCs) in larch (Larix kaempferi) adapt to subzero temperatures by deep supercooling (DSC). Recently, secondary metabolites possessing anti-ice nucleation activities and genes expressed in association with increased DSC ability have been characterized. However, role of soluble proteins on DSC mechanism is still unknown. In this study, detection of soluble proteins that are responsive to the changes in DSC ability in XPCs of larch was examined. DSC ability of XPCs in larch twigs was kept at the maximum level (LT50: <-50oC) in winter. After the artificial deacclimation of larch twigs of winter, DSC ability was promptly decreased to -34oC within a week. In parallel with this, levels of many winter-inducible proteins were also decreased. N-terminal amino acid sequencing of the proteins that are responsive to the changes in DSC ability revealed that some of them are homologous to the late embryogenesis abundant proteins.
