Functional groups of differentially expressed genes following Cr (VI) stress. 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 different concentrations of Cr (0 and 100 μM) under standard physiological conditions. Total RNA was extracted from the treated rice roots using and microarray was performed using one-cycle target labeling and control reagents. The hybridization data were analyzed using dCHIP software. For the genes that were differentially regulated, the gene ontology classification provided in http://bioinfoserver.rsbs.anu.edu.au/utils/GeneBins/ was used to assign genes to a hierarchical biological process using the Genebins.