Exploring the synergistic effects of melatonin and salicylic acid in enhancing drought stress tolerance in tomato plants through fine-tuning oxidative-nitrosative processes and methylglyoxal metabolism

•Melatonin and salicylic acid in combination highly improves tomato plant drought tolerance.•The combo treatment boosted non-enzymatic antioxidants, reduced oxidized glutathione under DS.•MT and SA lowered hydrogen peroxide, carbonyl, and thiol groups, activating oxide-nitrosative processes.•MT and SA raised l-CD activity, resulting in H2S and NO production, and lowered GSNOR activity.•MT and SA minimized methylglyoxal production, aiding improved DS tolerance in tomato plants.