Coordination of vacuolar proton-pumps during cold acclimation

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The geographical distribution of plant species as well as the growth and yield of crop plants are limited by their tolerance to low temperatures. Whereas plants from temperate regions increase their freezing tolerance during exposure to low but non-freezing temperatures in a process termed cold acclimation, chilling-sensitive plants fail to do so. Damage to cellular membranes is the major cause of freezing injury in chilling-sensitive plants and inactivation of the vacuolar H+-ATPase (V-ATPase) leading to cytosolic acidification has been reported to be one of the primary events after cold exposure. We have shown that cold acclimation in Arabidopsis involves an increase in V-ATPase activity that requires the presence and activity of a second enzyme, the vacuolar H+-PPase (V-PPase).We now propose to determine the molecular mechanism underlying the interplay of the two proton-pumps during cold acclimation as well as the function of their reversible modification via S-acylation. Moreover, we will perform a comprehensive analysis of the role of vacuolar H+-pumps during cold acclimation via genetically encoded sensors (pH and ATP/ADP ratio) as well as by metabolomics and lipidomics approaches. Based on the expected insights novel strategies for improved cold tolerance of crop plants will be developed.