Endophyte mediated activation of defense enzymes in banana plants pre-immunized with covert endophytes

Abstract

Fusarium oxysporum is typically a soil-borne fungus which causes major economic loss by inducing necrosis and wilting symptoms in many plants. Management of Fusarium wilt is achieved mainly by the use of chemical fungicides which adversely affects the soil health. Efficacy of chemical fungicide is often limited due to polyphyletic nature of the pathogen. Our study is aimed to assess the potential and ability of endophytes isolated from banana to activate innate plant immune responses. In the present study, it was observed that accumulation of defense related enzymes such as Peroxidase (PO), Phenylalanine ammonia lyase (PAL) and Polyphenol Oxidase (PPO) has been increased in plantlets that were treated with a mixture of endophytic inoculum such as Trichoderma reesei (UH EF), Polyporus vinctus (AAU EF) and Sphingobacterium tabacisoli (UH EB). Moreover, it was also observed that compared to individual inoculum treatments, treatments with a mixture of inoculums were found more effective in managing Fusarium wilt disease under in vivo conditions. Based on these results, it is concluded that the consortia of Trichoderma reesei (UH EF), Polyporus vinctus (AAU EF) and Sphingobacterium tabacisoli (UH EB) could be a promising biological control agent that can trigger systemic resistance against Fusarium wilt of banana in susceptible cv. Rasthali (Malbhog) planlets.