Abstract
Seed storage proteins are synthesized on rER and transported into protein bodies via the specific transport vesicle, called PAC vesicle. To identify a gene that determines the fate of seed proteins during the transport process, we generated a transgenic Arabidopsis expressing a fusion protein containing one of the storage protein, 2S albumin and selectable marker enzyme, phosphinothricin acetyltransferase. Despite the accumulation of the fusion protein, the transgenic plant was sensitive to a herbicide, phosphinothricin. We mutagenized seed of the transgenic plant, and obtained pav1 mutant that became resistant to the herbicide. pav1 has slender and curly leaves, and accumulates precursors of seed storage proteins (2S albumin and 12S globulin) in seeds. Electron microscopic analyses revealed that the pav1 seed contains unknown vesicles that are not found in wild type seed. The result suggests that pav1 mutant has defect in a gene requiring intracellular transport of seed storage proteins.
