Expression patterns of rice GST genes in various tissues/organs and developmental stages. (A) Hierarchical clustering analysis of 71 GST genes represented on Affymetrix Rice Genome Array is shown. For clustering we used average log signal values for three biological replicates of each sample after normalization of the raw data (Additional file 6). The color scale for log signal values is shown at the bottom. Clusters (I-XVI) are marked on the right. ML, mature leaf; YL, Y-leaf; SAM, shoot apical meristem; P1-P6, stages of panicle development; S1-S5, stages of seed development. (B) Real-time PCR analysis of selected genes to validate their differential expression during various stages of development. The mRNA levels for each gene in different tissue samples were calculated relative to its expression in root. The error bars represent standard deviation. ML, mature leaf; YL, Y-leaf; SAM, shoot apical meristem; Stage 1-3 represent stages of panicle development (Stage 1 corresponds to P1 and P2; Stage 2, P3 and P4; Stage 3, P5 and P6); Stage 4 and 5 represent stages of seed development (Stage 4 corresponds to S1 and S2; Stage 5, S3-S5).