Abstract
Vacuole plays an important role in maintaining the homeostasis of plant cell through the regulation of development of turgor pressure, the accumulation of various inorganic ions and metabolites and the degradation of discarded proteins. We have analyzed the contents of intact vacuoles directly and comprehensively by using CE-MS and FT-ICR-MS. The findings reveal the existence of organic phosphate compounds in the vacuole despite the presence of phosphatases. We have also prepared the transgenic Arabidopsis suspension-cultured cells over-expressing certain unknown tonoplast proteins and conducted the comparative analysis of the vacuolar metabolites of the wild-type and transgenic cells in order to elucidate the possible functions of the unknown membrane proteins. In the present study, possible mechanism of the entry of the phosphate compounds into the vacuole, using the genetically manipulated vacuoles, has been explored.
