Proteomic responses associated with freezing tolerance in the callus of the Tibetan alpine plant Saussurea laniceps during cold acclimation

Saussurea laniceps is a highly cold-tolerant, perennial, alpine herb that grows in Tibet, China. To reveal the reason why alpine plants can withstand large and frequent daily temperature fluctuation, we used S. laniceps callus to investigate the molecular mechanisms of freezing tolerance. The half lethal temperature (LT 50 ) of S. laniceps calli decreased to −11.7 °C after cold acclimation at 0 °C, while the LT 50 of calli cultured at 23 °C was −4.4 °C. Proteomic analyses showed that the abundance of each of 41 proteins significantly changed following acclimation at 0 °C. These proteins were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The proteins were found to be involved in stress response and defense, metabolism, energy production, transportation, transcription, cell structure, and photosynthesis. The possible implication of cold responsive proteins in plant adaptation to freezing stress is discussed. Our results provide a unique insight into the freezing resistance mechanism of S. laniceps .