Trend of changes in physiological parameters and semi-quantification gene expression for CapLEA-1 and Dehydrin 1 genes in chickpea genotypes under water deficit stress

Water deficit is the most important abiotic stress limiting crop productivity in most arid and semi-arid areas of the world and Iran. In order to achieve precise experimental comparisons, the response of chickpea genotypes MCC508 and MCC 521 to water deficit was evaluated and then expression of the genes assessed under the same stress situation. Decreasing trend of Relative Water Content (RWC) was significantly less in MCC508 compared with MCC521, especially after 24 hours (p≤0.05). Membrane Stability Index (MSI) was also higher in MCC508 whereas electrolyte leakage and Malondialdehyde (MDA) accumulation were almost stable but increased 1.2-fold relative to control after four days stress. Proline was accumulated up to 16.8 and 9.4 µ mol g-1FW in MCC508 and MCC521 after 4 days, which indicated an increase of 5.1 and 3.8 fold related to the control, respectively. Semi-quantification gene expression analysis for Dehydrin1and CapLEA-1 showed different response to water deficit for each genotype. Both of these genes up-regulated in tolerant genotype MCC508 with the amount of 4 and 2.1 fold compared to their respective control (p≤0.05) so that the up-regulation trend steadily continued under the stress situation. However, CapLEA-1 expression was not significantly regulated in the sensetive genotype; instead, Dehydrin1regulation was significantly evident as much as 1.4 fold increase and then decreased (p≤0.05). It, therefore, seems that stable, high up-regulation of Dehydrin1and CapLEA-1 genes and their function (stability of lipids and cell memebrane, correct protein folding and detoxificaton) might be a possible reason for high tolerancy response to water deficit in MCC508 compared to MCC521.