Chromosomal distribution of rice GST genes. The chromosome number is indicated at the top of each chromosome. GST genes localized on duplicated chromosomal segments are connected by lines. The genes labeled on left side are oriented from bottom to top and those on right side are oriented from top to bottom on rice chromosomes. Six clusters (three on chromosome 1 and one each on chromosome 1, 10 and 12) of tandemly arranged GST genes are indicated in boxes. Exact position of each GST gene on rice chromosome pseudomolecules is given in Additional file 1.