Co-regulation patterns of differentially accumulated transcripts in xylem formation. A total of 10,380 transcripts differentially accumulated in xylem formation were clustered into 14 groups using the Pearson correlation on the Subio platform. The graphs show the average expression profile of each cluster; changes are on a log2 scale. The gene expression pattern is shown as A) upregulation and B) downregulation during xylem formation. The description and expression profile of the individual targets are summarized in Additional file 2.