Leaf Proteome Analysis in Brassica rapa L. (Inbred line Chiifu ) using Shotgun Proteome Approach

Through high throughput shotgun proteomics approach, the proteome of seedling leaf of Brassica rapa L. was identified. From three biological replications, a total of 2,122 non-redundant proteins of Brassica rapa L seedling leaf were identified, with a wide range and unbiased physiochemical properties. Their pI values ranged from pH 4.27 (Bra004590) to pH 11.81 (Bra013905). Their molecular weight (MW) ranged from 5.6 kDa (Bra006908) to 534.5 kDa (Bra028068). Gene ontology enrichment analysis revealed that these proteins were associated with cellular process, metabolic process, and enriched catalytic activity compared to whole brassica proteins. The highest presented protein in Brassica rapa seedling leaf was RuBisCO, accounting for 11.56% of total leaf proteins. Also, many ribosomal proteins were identified. The relative amount of all ribosomal proteins comprised 8.47% of total leaf proteins. The relative amount of two RuBisCO and ribosomal proteins was about 20% of total leaf proteins. Thus to detect proteins presenting low abundance, additional fractionating procedure to remove RuBisCO and ribosomal proteins is required.