Triagem de isolados de Trichoderma spp. produtores de compostos orgânicos voláteis com atividade inibitória sobre Macrophomina phaseolina

Abstract

AVANZO, I. L. R. Selection of Trichoderma spp. isolates producing volatile organic compounds (VOCs) with potential for the biocontrol of Macrophomina phaseolina. finnal work, 42 p. 2026. Abstract: A diversity of polyvalent, multifunctional strains of Trichoderma spp. has been widely used in the biological control of plant pests and diseases, being recognized for its effectiveness and for contributing to sustainable agricultural practices. In this study, 21 isolates including both wild-type and transformed strains aimed at improving characteristics related to the antagonistic potential of lineages of Trichoderma spp. were analyzed to identifying those capable of producing volatile organic compounds (VOCs) with antagonistic activity against Macrophomina phaseolina, a phytopathogen responsible for charcoal rot in soybean crops. The assay was carried out in vitro using the dual plate technique, which enables microbial interaction through a shared atmosphere without direct contact. The experiment was conducted in a completely randomized design, consisting of 21 Trichoderma spp. isolates paired with one isolate of the pathogen (M. phaseolina), with three replicates per combination, totaling 63 experimental units (excluding the control treatmentss plates containing only the phytopathogen and plates containing only Trichoderma spp.). Plates were incubated at 27 °C, under a 12-hour photoperiod. After complete colonization of the control platess, colony diameters (mm) were measured using a digital caliper, and the mean percentages of mycelial growth inhibition were calculated. Data were subjected to analysis of variance, and means were compared using the Scott-Knott test at 5 % significance level, using the R software. The results showed variability among the isolates, with values ranging from 6.34% to 19.19%, indicating good experimental precision for the evaluated variables. The confrontation with M. phaseolina revealed that the isolates IF 113, IF 123, IF 126, IF 127, IF 131, IF 134, and IF 135 exerted greater suppression of pathogen’s mycelial growth, indicating the production of volatile compounds with inhibitory effects. Therefore, the identification and selection of these Trichoderma spp. isolates, both wild-type and transformed, thar wxhibit inhibitiory activity against M. phaseolina, represent important steps toward advancing the development and application of more effective and sustainable biocontrol agents in agriculture.