Chitinase from the Latex of Ficus benjamina L. Displays Antifungal Activity by Inducing ROS Generation and Structural Damage to the Fungal Cell Wall and Plasma Membrane

Abstract

Background: Chitinases are plant defense-related proteins with a high biotechnological potential to be applied in agriculture.

Objectives: This study aimed to purify a chitinase from the latex of Ficus benjamina.

Methods: An antifungal class I chitinase, named FbLx-Chi-1, was purified from the latex of Ficus benjamina after precipitation with 30-60% ammonium sulfate and affinity chromatography on a chitin column and antifungal potential assay against phytopathogenic fungi important to agriculture.

Results: FbLx-Chi-1 has 30 kDa molecular mass, as estimated by SDS-PAGE and the optimal pH and temperature for full chitinolytic activity were 5.5 and 60ºC, respectively. FbLx-Chi-1 is a high pH-, ion-tolerant and thermostable protein. Importantly, FbLx-Chi-1 hindered the growth of the phytopathogenic fungi Colletotrichum gloeosporioides, Fusarium pallidoroseum, and Fusarium oxysporum. The action mode of FbLx-Chi-1 to hamper F. pallidoroseum growth seems to be correlated with alterations in the morphology of the hyphal cell wall, increased plasma membrane permeability, and overproduction of reactive oxygen species.

Conclusion: These findings highlight the biotechnological potential of FbLx-Chi-1 to control important phytopathogenic fungi in agriculture. In addition, FbLx-Chi-1 could be further explored to be used in industrial processes such as the large-scale environmentally friendly enzymatic hydrolysis of chitin to produce its monomer N-acetyl-β-D-glucosamine, which is employed for bioethanol production, in cosmetics, in medicine, and for other multiple applications.

Keywords: Biotechnological application; ROS; antifungal; chitinases in the industry; enzymatic hydrolysis; protein purification.