Abstract:

The three-year-old seedlings of Vaccinium uligiuosum L. were selected as testing materials. The seedlings were exposed to the control（23 ℃，daylength 14 h），low-temperature and short day（4 ℃，daylength 10 h） and low-temperature and long day（4 ℃，daylength 14 h）under controlled environment chamber for 21 d respectively. The changes in the protein expression of shoot tissues after treatment were recorded. iTRAQ-based quantitative proteomics techniques were used in this study. The results showed that of 5 972 proteins and 600 differential expression proteins identified by a mass spectrometric analysis，140 proteins were significantly up-regulated and 114 were significantly down-regulated in low temperature and short-day vs control；255 proteins were significantly up-regulated and 122 were significantly down-regulated in low temperature and long-day vs control；39 proteins were significantly up-regulated and 187 were significantly down-regulated in low temperature and short-day vs low temperature and long-day. They included proteins were mainly involved in（1）RNA metabolism；（2）protein posttranslational modification；（3）carbohydrate metabolic；（4）energy production and conversion；（5）lipid metabolism；（6）secondary metabolites biosynthesis；（7）antioxidant and stress defense；（8）photosynthesis；（9）inorganic ion transport and metabolism. The differential expression proteins related to freezing tolerance were mainly induced by low temperature. In addition，expression of a few proteins is affected by both low temperature and photoperiod，and low temperature and short photoperiod are more favorable to freezing resistance acquisition. Cold acclimation increased significantly abundance of protein involved in RNA metabolism，protein posttranslational modification，antioxidant and defense responses，secondary metabolites biosynthesis，and lipid metabolism，revealed these metabolic pathways and related proteins may play an important role in freezing resistance mechanism in Vaccinium uligiuosum L.

Key words: Vaccinium uligiuosum, cold acclimation, proteomics, photoperiod, iTRAQ, freezing resistance