Self-Inhibitory Activity of Trichoderma Soluble Metabolites and Their Antifungal Effects on Fusarium oxysporum

Abstract

[EN] Self-inhibitory processes are a common feature shared by di erent organisms. One of the main mechanisms involved in these interactions regarding microorganisms is the release of toxic di usible substances into the environment. These metabolites can exert both antimicrobial e ects against other organisms as well as self-inhibitory ones. The in vitro evaluation of these e ects against other organisms has been widely used to identify potential biocontrol agents against phytopathogenic microorganisms. In the present study, we performed membrane assays to compare the self-inhibitory e ects of soluble metabolites produced by several Trichoderma isolates and their antifungal activity against a phytopathogenic strain of Fusarium oxysporum. The results demonstrated that Trichoderma spp. present a high self-inhibitory activity in vitro, being a ected in both their growth rate and the macroscopic structure of their colonies. These e ects were highly similar to those exerted against F. oxysporum in the same conditions, showing no significant di erences in most cases. Consequently, membrane assays may not be very informative by themselves to assess putative biocontrol capabilities. Therefore, di erent methods, or a combination of antifungal and self-inhibitory experiments, could be a better approach to evaluate the potential biocontrol activity of microbial strains in order to pre-select them for further in vivo trials.