Different Antifungal Activity of Anabaena sp., Ecklonia sp., and Jania sp. against Botrytis cinerea

Abstract

Water extracts and polysaccharides from Anabaena sp., Ecklonia sp., and Jania sp. were tested for their activity against the fungal plant pathogen Botrytis cinerea. Water extracts at 2.5, 5.0, and 10.0 mg/mL inhibited B. cinerea growth in vitro. Antifungal activity of polysaccharides obtained by N-cetylpyridinium bromide precipitation in water extracts was evaluated in vitro and in vitro at 0.5, 2.0, and 3.5 mg/mL. These concentrations were tested against fungal colony growth, spore germination, colony forming units (CFUs), CFU growth, and on strawberry fruits against B. cinerea infection with pre- and post-harvest application. In in vitro experiments, polysaccharides from Anabaena sp. and from Ecklonia sp. inhibited B. cinerea colony growth, CFUs, and CFU growth, while those extracted from Jania sp. reduced only the pathogen spore germination. In in vitro experiments, all concentrations of polysaccharides from Anabaena sp., Ecklonia sp., and Jania sp. reduced both the strawberry fruits infected area and the pathogen sporulation in the pre-harvest treatment, suggesting that they might be good candidates as preventive products in crop protection.

Keywords: Botrytis cinerea; algae; antifungal activity; cyanobacteria; polysaccharides; strawberry.

Figure 1

Effect of different POL concentrations on Botrytis cinerea colony growth rate. Treatment and dose factors and their interaction are significant, according to factorial ANOVA. F_(2,36) = 18.2, p < 0.0001 (for treatment factor), F_(3,36) = 27.8, p < 0.0001 (for dose factor), F_(6,36) = 2.7, p < 0.05 (for interaction). Columns are mean values ± SD. The same uppercase letter within each POL treatment and the same lowercase letter among concentrations indicates no significant differences according to Student–Newman–Keuls test (p < 0.05).

Figure 2

Infected area of strawberry fruit caused by Botrytis cinerea (a) and its sporulation (b) after pre-harvest treatment with different concentrations of polysaccharides from Anabaena sp. (AN), Ecklonia sp. (ECK), and Jania sp. (JAN). Polysaccharides and concentration factors and their interaction are significant, according to factorial ANOVA. (a) F_(2,240) = 270.0, p < 0.0001 (for treatment factor), F_(3,240) = 266.3, p < 0.0001 (for dose factor), F_(6,240) = 45.0, p < 0.05 (for interaction). (b) F_(2,96) = 23.0, p < 0.0001 (for treatment factor), F_(3,96) = 370.0, p < 0.0001 (for dose factor), F_(6,96) = 18.5, p < 0.05 (for interaction). Columns are mean values ± SD. The same uppercase letter within each POL treatment and the same lowercase letter within each concentration indicates no significant differences according to Student–Newman–Keuls test (p < 0.05).