Using Validamycin A for Salinity Stress Mitigation in Two Rice Varieties Differing in Their Salt Tolerance Level

WE PRESENT here the comparative protective potentiality of exogenously applied validamycin A, a potent inhibitor of trehalase as seed soaking prior to sowing in saline soil with salinity level (EC 10.06 dS/m) in mitigating NaCl toxicity and inducing salinity tolerance in two rice (Oryza sativa L.) cultivars (cv.), Sakha 103 (salt-sensitive) and Agami M5 (salt-tolerant). Salinity stress decreased starch and total soluble protein contents concomitantly with increasing total soluble sugars, proline and free amino acids in both cultivars. Validamycin A decreased the activity of trehalase which leads to the accumulation of trehalose in both cultivars of rice plants. Raising trehalose level in the plant tissues was accompanied by increasing the starch and protein content and appearance of new protein pattern of both cultivars. Application of validamycin A increased grain yield, 1000-grain weight and filled-grain percentage for both rice cultivars under saline field conditions. Soaking rice seeds with 30 mu M of validamycin A could alleviate the harmful effects of salinity stress.