Twenty one day old seedlings of the mutant and WT grown in hydroponic culture in three replications were subjected to 25% PEG stress for one hour. The leaf samples of stressed and control seedlings were collected and preserved in liquid nitrogen for RNA isolation. Total RNA from four samples i.e. mutant control (MC), mutant stress (MS), Nagina22 control (NC) and Nagina22 stress (NS) was extracted by following the manufacturer‰۪s instructions provided with SV Total RNA isolation system Kit (PROMEGA, USA). All the steps starting from cRNA preparation to hybridization were conducted following the instructions of Affymetrix (AffymetrixGeneChip Expression Analysis Technical Manual). Chips were washed and stained in the Affymetrix Fluidics Station 450, and then scanned using the Affymetrix Gene Chip Scanner 3000. The cell intensity data files (.CEL) generated by the Gene Chip Operating Software (GCOS 1.2).