Fig. S4.

Freezing experiments. All lines were either cold-acclimated at 4 °C for 8 d (With acclimation) or directly (Without acclimation) transferred to −7 °C for 16 h. Photos were taken 5 d after the freezing treatments. cob-6 was found to be resistant to freezing, and qPCR showed that CBF1 expression is significantly higher in control cob-6 plants compared with wild type, suggesting that the cell wall damage in cob-6 triggers a stress response that likely confers freezing tolerance. Bars indicate means ± standard deviation.