Effect of chitosan seed treatment as elicitor of resistance to Fusarium graminearum in wheat.

The potential ability of chitosan seed treatment to induce resistance in plants of durum wheat (Triticum durum) against the seed borne fungal pathogen Fusarium graminearum, one of the main causal agents of root and foot rot in wheat, was evaluated. The chitosan seed treatment efficacy was evaluated by biochemical analyses, comparing: seed treated, seed treated and inoculated with the fungus, seed not treated and inoculated, seeds not treated and not inoculated. The enzymatic activities of some enzymes involved in defense mechanisms were analysed: guaiacol peroxidase (POD), ascorbate peroxidase (APX), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL), as well as the phenol content. Seed treatment induced changes in the enzymatic activities and increased phenol production. Greenhouse trials were performed with inoculated soil and the disease incidence on the plants was significantly reduced by chitosan seed treatment. Finally, field trials were conducted with inoculated seeds and then treated with chitosan. The chitosan seed treatment induced a decrease in disease severity and enhanced quantitative yield parameters, suggesting the possibility of the use of chitosan as a seed treatment in crop protection in order to improve the plant defense response.