Abstract
Seed storage proteins are synthesized on rER as precursors, are transported to protein storage vacuoles, and then are converted into the mature forms. We have isolated vacuolar sorting mutants for storage proteins. atvsr1 mutant secretes the storage protein precursors to the extracellular space 1). mag2 mutant accumulates the precursors in the novel structures derived from rER within cells 2). Different accumulation manners of the precursors in atvsr1 and mag2 indicate that AtVSR1 and MAG2 function in the different step of the storage protein transport from each other. We generated a double mutant of atvsr1 and mag2. The double mutant germinates and grows normally. Electron microscopy revealed that the double mutant accumulated the storage protein precursors in both intracellular and extracellular spaces of seeds.
1) Shimada et al. Proc. Natl. Acad. Sci. USA, 100, 16095 (2003)
2) Li et al. Plant Cell, (2006) in press
