Sucrose starvation causes a loss of immunologically detectable pyrophosphatase and V-ATPase in the tonoplast of suspension-cultured tobacco cells.

摘要

The effect of sucrose starvation on logarithmically growing suspension cultures of tobacco BY-2 cells was investigated by immunogold electron microscopy with antisera against pyrophosphatase (PPase) and V-ATPase. In normal cells PPase was located atthe plasma and tonoplast membranes, whereas V-ATPase was restricted to the tonoplast. After 32 h of growth in the absence of exogenous sucrose, both PPase and V-ATPase polypeptides were no longer detectable in the tonoplast by this method. By contrast,plasma membrane-bound PPase appeared to be unaffected by sucrose deficiency. These results are discussed in terms of a down-regulation of electrogenic pumps in the tonoplast.