Drought-Stress Induced Changes in the Expression of Acid Phosphatases in Drought Tolerant and Susceptible Cultivars of Wheat

The variability in acid phosphatase activities was studied with an objective to find out its physiological role in response to drought stress. The effect of drought stress on acid P-ase activity in relationship with phosphorus was studied in drought tolerant (C-306) and drought sensitive (HD-2004) cultivars of wheat. Drought stress was imposed by withholding water irrigation to the growing seedlings in the net house conditions. The tissues (leaves and grains) were separated and acid P-ase activity, western blotting studies were carried out. After drought stress, a significant increase in acid P-ase activity was observed in leaves and grains of drought tolerant cv. C-306. However, no change was observed in drought sensitive cv. HD-2004. Immuno-blotting analysis also revealed similar type of induction of wPase-94 (band detected using antiserum in western blot analysis) expression under drought stress conditions. Imposition of drought stress caused significant decrease in phosphorous level (Pi) in both the varieties at all the stages of development. However, increased acid P-ase activity coupled with low Pi level in drought tolerant cv. 306, indicated variety specific key role of acid P-ases under drought stress in maintaining Pi level. Based upon these results, a possible physiological role of acid P-ases in wheat is discussed.