Comparative leaf proteomics of Brassica napus genotypes with distinctive levels of early cold acclimation

Rapeseed/canola (Brassica napus L.) is considered amongst the “big four” oilseed crops with varying degrees of cold tolerance. Differential protein expression of cold acclimated young leaves of two canola genotypes, Sari Gul (spring type cold-sensitive) and Zarfam (winter type cold-tolerant), were determined via two dimensional polyacrylamide gel electrophoresis. Seedling leaves were cold acclimated by temperature regime and collected before and after cold treatment at 4 and −4 °C after 24 h, proteins were isolated and separated on 2-DE. Gel analysis of 651 protein spots revealed that 19 protein spots were significantly different between the two conditions in response to early cold acclimation. Following nanoflow liquid chromatography–tandem mass spectrometry, 19 protein sequences were identified in gel spots, which were reported for the first time in response to early cold acclimation in B. napus and nearly half of them were associated with various aspects of chloroplast physiology; suggesting that the cold stress response of B. napus is achieved, at least partly, by regulation of chloroplast function. Our work has provided novel insights into the plant response to cold stress and should pave the way for future studies towards functional analysis of candidate genes in cold response.