Confers salt tolerance by triggering the expression of stress-responsive genes. H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate Binds 2 magnesium or manganese ions per subunit. Expressed in roots, leaves, stems, flower, and trichomes. Induced in shoots by drought in roots by abscisic acid (ABA), and both in roots and shoot by salt stress. Decreased salt tolerance. Belongs to the PP2C family.