Abstract
Seed storage proteins are synthesized on rough endoplasmic reticulum as larger precursors. The precursors are transported to protein storage vacuoles (PSVs) by vesicle- mediated machinery, and then are processed into their mature forms. Previously, we identified VSR1 as a vacuolar sorting receptor for seed storage proteins in Arabidopsis. Seed storage protein precursors are accumulated in the extracellular space in the seeds of VSR1-deficient mutant. To identify the factors responsible for the receptor-dependent vacuolar sorting of storage proteins in maturing seeds, We screened some mutants that accumulated storage protein precursors in the seeds of Arabidopsis. We also applied reverse genetic approach with various T-DNA inserted lines of retromer components. We characterized the storage proteins patterns accumulated in their mutant seeds by immunoblot analysis with specific antibodies against storage proteins. Retromer-deficient mutants also showed vacuole fragmentation, embryogenesis defect, dwarfism and early leaf senescence.
