Induction of defense response mediated by inulin from dahlia tubers (Dahlia sp.) in Capsicum annuum

Abstract

Phytophthora capsici is the causal agent of chili wilt. Among the strategies for its control is the use of resistance inducers. Fructans are molecules with interesting biological properties, including the ability to induce resistance mechanisms in some plants. In this work, the protective effect of four concentrations inulin from dahlia tubers on chili infected with P. capsici was evaluated. The concentration that showed the highest protection was chosen to evaluate the induction of defense response through the enzymatic activity of β-1,3 glucanases, peroxidases and the production of total phenolic compounds. Inulin showed a protective effect against infection at concentrations of 100 to 300 μM, as symptoms decreased and seedlings showed improved vegetative development. It was observed that inulin at 200 μM concentration was able to induce an effective defense response associated with increased activity of β-1,3 glucanases and peroxidases through a local and systemic response in seedlings. This response was differentiated between seedlings treated with inulin and seedlings infected with P. capsici. It was concluded that inulin has the ability to protect chili bell pepper from P. capsici by induction of resistance.