ABSCISIC ACID-RESPONSIVE PROTEINS INDUCE SALINITY STRESS TOLERANCE INFINGER MILLET (ELEUSINE-CORACANA GAERTN) SEEDLINGS

Pretreatment of finger millet (Eleusine coracana Gaertn.) seedlings wi th 200 mM NaCl significantly enhanced the survival of the seedlings at a lethal stress of 400 mM NaCl and subsequent recovery growth when th e stress was withdrawn. However, when the pretreatment included 10 muM abscisic acid (ABA) along with 200 mM NaCl, the seedlings could survi ve lethal stresses of 500 and 600 mM NaCl and recover remarkably upon withdrawal of stress. Pretreatments with ABA and NaCl resulted in the appearance of several new proteins of 18, 23, 31, 45, 48, 54, 66 and 6 8 kDa. The ABA responsive proteins were heat-stable and their accumula tion increased with ABA concentration in the medium. This increase was also associated with an enhanced tolerance of the seedlings to lethal levels of salinity stress. ABA alone however was not effective either in the synthesis of ABA responsive proteins or in imparting tolerance to salinity stress. S-35-methionine incorporation studies indicated t he synthesis of 21, 26, 39, 45, 68, 70, 74 kDa proteins of which 21 kD a was the prominent polypeptide synthesized during induction.