Differential response of proline metabolizing enzymes in drought tolerant and drought sensitive varieties of wheat (Triticum aestivum L.) during grain development

Wheat (Triticum aestivum L.) plants exposed to drought stress show unfavorable changes at the cellular and molecular level. Under draught stress plants adjust osmotic mechanism by production of proline in the cell. Proline metabolizing enzymes are crucial for selection of draught stress tolerance by accumulation of compatible osmolytes. The present study depicts the activities of two major proline metabolizing enzymes viz. ∆1 pyrroline-5-carboxylate synthetase and ∆1pyrroline -5-carboxylate reductase are increased under drought stress compared to irrigated condition in both leaves and developing grains of wheat varieties. Plants accumulate proline under drought stress condition which is normally catabolized to pyrroline-5-carboxylate by proline oxidase. The activity of proline oxidase is decreased under drought stress both in leaves and developing grains there by provides osmoprotection and made plants tolerant to drought.