The Activity of Cell-Wall Modifying β-1,3-Glucanases in Soybean Grown in Presence of Heavy Metals

Abstract

Cell walls represent the first barrier that can prevent the entrance of toxic heavy metals into plants. The composition and the flexibility of the cell wall are regulated by different enzymes. The ß-1,3-glucanases control the degradation of the polysaccharide callose as a flexible regulation mechanism of cell wall permeability and/or its ability to bind metals under stress conditions. The profile and activity of ß-1,3-glucanases in the presence of heavy metals, however, has rarely been studied. Here we studied these enzymes in four soybean varieties (Glycine max) grown in the presence of cadmium ions. These analyses revealed three acidic and one basic enzyme isoforms in each soybean variety, but only two of the acidic isoforms in the variety Moravians were substantially responsive to the presence of Cd²⁺. Since the responses of certain glucanases were detected mainly in the varieties sensitive to metal and accumulating high amounts of metals, we assume their role in the defense rather than strategic metal sequestration.