Co-regulatory networks of genes differentially modulated in H471 under drought stress (false discovery rate 0.05). Co-regulation analysis was based on the calculation of pairwise Pearson correlation coefficient (PCC) of logarithmic expression values (with a cutoff of 0.75) in Rice Oligonucleotide Array Database. Four subgroups, indicated with letters from A–D which also distinguished by shapes, were identified as their putative functions. Different colors indicate genes with unique function class: olive, Ca2+ signal related; gold, receptor kinase; blue, kinase; violet, TF; green, K + transporter; Pink, redox regulation; black, osmotin; red, carbohydrate metabolism. The thickness of the edges is proportional to the PCC. Asterisks indicate the genes located in the introgression segment from P28. Arrows indicate up- and down-regulated in response to drought stress, respectively; and 1, 3 and B with arrows show 1 day, 3 days, both 1 and 3 days drought stress, respectively.