Proteomic Profiling of the Aleurone Layer of Mature Arabidopsis thaliana Seed

The aleurone layer of mature Arabidopsis thaliana seed plays important roles in seed germination and dormancy. However, the proteomic profile of this cell layer is unknown partly because it is difficult to separate this thin cell layer from the mature seeds. In this study, we have used a simple technique to separate the aleurone layer along with the seed coat following germination of seeds and determined for the first time the putative protein composition of this cell layer. By subjecting the total proteins extracted from the seed coat to 2D gel electrophoresis followed by liquid chromatography/tandem mass spectrometry, we identified four AGI loci, AT4G28520, AT5G44120, AT1G03880, and AT1G03890; all of which belong to the seed storage family of proteins. Because in Arabidopsis the diploid aleurone cells of the seed coat perform protein storage functions similar to that of triploid endosperm of other plant species, it is assumed that the above AGI loci are associated with the aleurone layer of the seed coat.