Modulation in expression and activity of glutathione-S- transferase during Cr-stress. Expression profiles of differentially expressed GSTs after Cr (VI), As (V), Cd and Pb stress in rice root (A). The rice variety IR-64 was germinated and allowed to grow for 5 d at 37°C and then transferred to Hewitt solution for growth. After 10 d of growth, seedlings of uniform size and growth were treated with 100 μM of Cr (VI), As (V), Cd, and Pb under standard physiological conditions. Total RNA was extracted from the treated rice roots and microarray was performed using one-cycle target labeling and control reagents. The hybridization data were analyzed using dCHIP software. The color scale (representing log signal values) is shown at the bottom. Effect of 100 μM Cr (VI) on the level of GST-activity (B) in rice root after 24 h and 7 days treatment.