Relações entre testes com metabólitos e seleção de isolados de Trichoderma spp. antagônicos a Sclerotinia sclerotiorum

Abstract

Fungi of the Trichoderma genus have a versatility of action, as they can act by direct and/or indirect mechanisms. In view of this, multivariate analysis has been used in order to summarize and identify correlations among different mechanisms of biological control. We aimed to evaluate the antagonism of 16 Trichoderma spp. isolates against Sclerotinia sclerotiorum and identify the variables that best explain the antagonistic activity of Trichoderma spp. isolates against the pathogen in vitro. For that, isolates were confronted with the pathogen in paired culture (PC) and had the effect of their metabolites on the pathogen growth evaluated in volatile (VM), thermolabile (TLM), and non-thermolabile metabolite (NTLM) assays. Isolate CEN654 allowed only 17.1, 9.5, and 0.3% of pathogen growth in relation to the control in the VM, TLM, and NTLM assays respectively, standing out from the other isolates in the principal component analysis (PCA). The PCA also suggested that the PC and TLM assays are more suitable for the in vitro selection of isolates with antagonistic activity against S. sclerotiorum than the VM and NTLM ones.