Comparative proteomic analysis reveals differential protein and energy metabolisms from two tobacco cultivars in response to cold stress

Low temperature is an important abiotic stress for plant development and has serious effects on crop production. Because tobacco is sensitive to low temperature, it is suitable for analyzing the mechanisms of cold response in plants. In the current study, NC567 and Taiyan8, two cultivars with different sensitivities to low temperature, were used in Isobaric Tags for Relative and Absolute Quantitation (iTRAQ)-based proteomics to uncover their different mechanisms in response to cold stress. A total of 4317 distinct proteins were identified and the differentially expressed proteins in four comparison sets were used for further analysis. The gene ontology (GO) analysis indicated that the majority of differentially expressed proteins were in the categories involved in metabolic and cellular processes. Surprisingly, there were 55 proteins decreased in NC567, but increased in Taiyan8 in response to cold, while the levels of 42 proteins were lower in Taiyan8 than NC567 at normal temperature, but higher in Taiyan8 than NC567 under cold treatment, suggesting different responses to cold stress in these cultivars. The levels of polypeptides involved in protein synthesis and degradation, photosynthesis, and respiration, as well as ROS scavenging, were different in the comparison sets, implying that protein and energy metabolisms may be important for the establishment of cellular environment at low temperature. In conclusion, our study identified the potential pathways involved in low-temperature response of tobacco and provides hints for the further improvement of cold tolerance in crops.