Fig. 2. Validation of the microarray data by real-time RT–PCR. Nine selected genes were subjected to real-time RT–PCR, and their relative expression levels in the control, 1 day and 30 days cold-acclimated groups were compared. Basically, the expression levels detected by real-time RT–PCR were consistent with the microarray data. The values were normalized to β-actin. Values are means ± s.d. (N=4 or 5). Different letters above the bars indicate significant differences (one-way ANOVA, Tukey's pair-wise comparison).