Biochemical characterization of wheat seed lectin and its antifungal activity against seed-borne fusarium graminearum in-vitro and in-situ

The objective of the study was to examine the inhibitory effect of lectin as a glycoprotein isolated from wheat seeds (Triticumaestivum) against the fungus Fusarium graminearum in vitro. The purified wheat seed lectin is a glycoprotein composed of two subunits of 111 and 15 kDa with an isoelectric point of 6.0. The most abundant sugars found in lectin are galactose (160 mg) followed by galacturonic acid (80 mg) and arabinose (60 mg) per 100g sample respectively. The antioxidant activity of the wheat seed lectin investigated in the study revealed dose-dependent variations in DPPH (2,2- Diphenyl-1- picrylhydrazyl) free radical scavenging activity, with a low IC50 value (4.3 µg/mL). Lectin prevented the growth of mycelium at a broad concentration range (100–400 µg/mL). Maximum inhibition was observed at a concentration of 400 µg/mL, which is equivalent to 77.77% of linear growth reduction after seven days of incubation at 25ºC. The effect of the seed dressing treatment with lectin at various concentrations (1000, 200, and 400 µg/mL) on the percentage of preand post-emergence of damping-off grown in Fusarium graminearum infested soil under greenhouse conditions was also estimated. The results reveal that all the examined lectin concentrations decreased damping-off in comparison to the control. The study shows that lectin can be applied as an antifungal agent against wheat damping-off. (author)