Combined antifungal activity of cyclic lipopeptides and cinnamon extract: From in vitro experiments to the control of Fusarium wilt of banana

Abstract

Abstract Fusarium wilt of banana (FWB) caused by soil-borne Fusarium oxysporum f.sp. cubense (Foc), is a widely distributed disease that generates devastating losses in banana. The most aggressive Foc tropical race 4 (TR4), attacks Cavendish clones and a diverse range of other banana varieties. Management practices to suppress Foc are emerging, however they are challenging. Therefore, enhancing biological control activities could potentiate FWD control practices. Here we determine the antifungal synergistic effect of plant-based cinnamon (Cinnamomum zeylanicum) extract and Bacillus tequilensis EA-CB0015 cyclic lipopeptides against Fusarium sp. strains in vitro and in banana plants in greenhouse. We found, through a bioprospecting assay of 17 plant-based natural extracts, that cinnamon was highly active against Foc isolate IB (race 1). Furthermore, cinnamon and cyclic lipopeptides inhibited different Fusarium spp. strains belonging to race 1 and TR4, and their combination increased 1.4-fold the effect of the single extracts in vitro. Our results demonstrate that soil concentration of F. odoratissimum TR4-II5 was reduced by 78.5% with the combination treatment in a soil microcosm system. Although, while the combination reduced external FWB symptoms, only cinnamon extract had a significant impact on internal symptoms in plants. Taken together, the biological control effect of cyclic lipopeptides with cinnamon extract on Fusarium spp. supports their function towards increasing soil health and reducing disease intensity and suggests that the combination enhances the effect of the single extracts.