Castor (Ricinis communis) is a model plant for studying non-photosynthetic oilseed metabolism. Castor seed accumulate approximately 60% oil by dry weight, mostly within the seed endosperm. Knowledge of global protein expression during Castor seed development will provide insight into varying metabolic pathways of non-photosynthetic oilseeds compared to photosynthetic oilseeds.

Castor seed were analyzed using two-dimensional Difference Gel Electrophoresis (DIGE) at 2, 3, 4, 5 and 6 weeks after flowering. Two-dimensional gel reference maps are now available for proteins with pI values from 4 to 7 (gel of pI 4-7) and pI 3-10 (gel of pI 3-10). Altogether, expression profiles for 522 proteins were identified by liquid chromatography-tandem mass spectrometry when searched against the recently released castor genome. These identified proteins are highlighted on the reference maps and the functional classification table (protein table). Proteome reference maps contain clickable spots linked to quantitative expression data and protein identification data.