Updated project metadata. Chlorophyll plays critical roles in photosynthetic light harvesting, energy transduction and plant development. In this study, a novel wucai (Brassica campestris L.) germplasm with green outer leaves and yellow inner leaves at the adult stage (W7-2) was used to examine chlorophyll metabolism response to cold acclimation. A green leaf wucai genotype without leaf color changes named W7-1 was selected as the control to evaluate the chlorophyll metabolism changes of W7-2. Compared to W7-1, the contents of chlorophyll a (Chl a) and chlorophyll b (Chl b) in W7-2 were significantly reduced at five developmental stages (13, 21, 29, 37 and 45 days after planting (DAP). An iTRAQ-based quantitative proteomic analysis was carried out at 21 and 29 DAP according to the leaf color changes in both of genotypes. A total of 1409 proteins were identified, of which 218 showed differential accumulations between W7-2 and W7-1 during the two developmental stages.