Method for preparing a formulation for inducing an immune response of a plant to a pathogen, and formulation

A method to prepare a formulation to induce an immune response of a plant susceptible to a pathogen, characterized by the fact that it comprises:

• (a) purifying oligogalacturonide compounds, from the product of the partial enzymatic hydrolysis of polygalacturonic acid during the pectin refining process,
• on which the hydrolysis reaction is conducted by a pectinase complex (pectin methylesterases, endopolygalacturonases and exopolygalacturonases), obtained from Aspergillus niger, at a temperature ranging from 26° C. to 36° C., stirring ranging from 100 to 200 rpm and pH between 3.8 and 4.5;
• (b) boiling the obtained solution at a temperature of 100° C. for 10 min. for enzymatic inactivation;
• (c) diluting the obtained solution at 0.5% with 50 mM sodium acetate solution;
• (d) adding ethanol to the obtained solution, obtaining a solution with a concentration of 11%;
• (e) maintaining the solution of step (d) incubated for 16 hours at a temperature of 4° C. so as to precipitate the oligogalacturonides;
• (f) centrifuging the solution of step (e) at 30,000 g for 30 min., obtaining a formulation containing powdered oligogalacturonides and soluble in water;
• (g) re-suspending the compound in water so as to obtain a solution with a concentration of 1 mg/mL.