FOR1061, Subproject: Dynamic Storage Functions of Plant Vacuoles During Cold and Osmotic Stress

Transport processes across the vacuolar membrane are critical for multiple elementary plant functions including stress tolerance. In the previous funding period we made remarkable progress (i) in characterizing functional properties of vacuolar carriers using electrophysiological approaches, (ii) in understanding the mechanisms underlying the energization of the tonoplast, (iii) in the unraveling of prevacuolar processes, (iv) in determining the impact of selected membrane proteins on plant performance, (v) in elucidating posttranslational modifications of tonoplast proteins, (vi) in characterizing vacuolar export proteins, and (vii) in identifying novel targeting mechanisms of vacuolar membrane proteins. In the proposed funding period we will extend our efforts on the regulation of tonoplast-located proton pumps, on the biogenesis of vacuoles and protein targeting to the tonoplast, on functional analyses of proteins affecting post-translational modification, on the effects of micronutrient movement (metals) across the tonoplast on stress tolerance, and on the analysis of altered (improved?) stress tolerance in multiple loss-of-function or overexpressor mutants.

Due to the complexity of the techniques required to conduct such comprehensive analyses it is necessary that the groups involved also cooperate closely in the future. The anticipated results will help to understand the function of higher plant vacuoles, to position this essential organelle and its molecular responses in the context of primary metabolism, and to develop strategies to improve (i) storage of agriculturally important compounds, (ii) plant productivity and (iii) abiotic stress tolerance. We expect that further concerted cooperation on dynamic vacuolar storage processes will foster the internationally appreciated position of German research in this field.