Burdock Fructooligosaccharide Induce Plant Systemic Resistance

Burdock Fructooligosaccharide is a kind of oligofructose extracted from the roots of salt-tolerant Burdock (Arctium lappa L.) by our group, which consisted of 12 fructofuranose and 1 glucopyranose. In this paper, resistance to plant diseases was systematically studied, which induced by Burdock Fructooligosaccharide in cucumber. And the mechanism of induced resistance was demonstrated through changes of enzymes activity and endogenous signal molecules content. Followsing conclusions can be made from the study.1 Resistance effects of cucumber to anthracnose were studied after employing 5.0mg/mL Burdock Fructooligosaccharide on cucumber seedlings. The results show that cucumber seedlings had significant resistance to anthracnose after induced by 5.0mg/mL Burdock Fructooligosaccharide. Compared with the controls, the number of lesions decreased 50.01% in cucumber leaves previously treated with Burdock Fructooligosaccharide after inoculated Colletotrichum lagenarium, at the same time the area of lesions decreased 56.83% in cucumber leaves.2 Effects of different concentration Burdock Fructooligosaccharide were studied on activities of defense enzymes and β -1,3-glucanase in cucumber leaves. The results show that the activities of those enzymes positively correlated with disease resistance increased after induced by Burdock Fructooligosaccharide, such as PPO, SOD, POD, β -1,3-glucanase, and the activity of CAT negatively correlated with disease resistance decreased after induced by Burdock Fructooligosaccharide. Different enzymes reached maximum or minimum activities at different concentrations of Burdock Fructooligosaccharide. PPO, SOD, POD, β -1,3-glucanase reached maximum activities at concentrations of 7.0, 5.0, 3.0, 5.0mg/mL Burdock Fructooligosaccharide respectively, and CAT reached minimum activity at concentration of 5.0mg/mL Burdock Fructooligosaccharide. Therefore, the optimum concentration of Burdock Fructooligosaccharide which induce disease resistance of plants is 3.0~7.0mg/mL.3 Effects of 5.0mg/mL Burdock Fructooligosaccharide on activities of defense.