Figure 1

Summary of microarray analysis showing the expression patterns of chilling stress 'early response' genes. Temporal profiles of genes with ≥ 1.8-fold induction in one or more time points during the initial 24 hours at 10°C are shown. Expression values were normalized so thatmean of the ratio of median of all of the features is equal to 1. Left panel – Hierarchical clustering of 121 'early response' genes. Temporal expression clusters indicate multiple waves of gene induction. Scale of fold-change values is shown on the right side of the panel. Right panel – Binary hierarchical clustering of 'early response' genes. The genes induced at or above the 1.8-fold cut-off level were given a value of 1 (green), and those below the cut-off level a value of 0 (black). Clusters indicate that the genes can be categorized into two major groups: 'rapid response' (Group-I, induction initiated during the initial 2 hours) and 'slow response' (Group-II, induction initiated after 2 hours). Genes within each group exhibit either a sustained or transient induction during the initial 24 hours under chilling stress (see Additional files 1 and 2 for the list of genes in each group).