Estudo in vitro do potencial antagônico de isolados de Trichoderma spp. ao fitopatógeno Fusarium oxysporum

Abstract

The phytopathogen Fusarium oxysporum, belonging to the genus that causes the disease popularly known as fusariosis or Fusarium wilt, affects several agricultural crops worldwide. Its high degree of pathogenicity is associated with its ability to colonize the vascular system of plants, as well as the production of resistance structures in the soil, the chlamydospores. Considering the need for methods that contribute to agricultural development without causing damage to the environment and the population, biological control agents (BCAs) are now seen as an excellent artifice. Fungi of the genus Trichoderma can be considered cunning BCAs because they have numerous mechanisms with high antagonistic potential that impair spore germination, hyphal growth and chlamydospore development of various phytopathogens. The present work sought to evaluate the efficiency of Trichoderma spp. in the biocontrol of the phytopathogen F. oxysporum through pairing tests, enzymatic analysis, and production of secondary metabolites. All isolates had results considered satisfactory, according to the Bell scale, in the pairing test. However, in the volatile metabolites test, none of the isolates achieved an inhibitory effect. The analysis of non-volatile metabolites showed that the isolate of T. asperelloides TR-356 can inhibit the mycelial growth of F. oxysporum without the need for direct contact between the hyphae. The enzymatic tests indicated that the isolates of Trichoderma spp., when in the presence of macerated mycelia of the phytopathogen F. oxysporum, showed hydrolytic activities of important compounds present in the cell wall of the host, with emphasis in this action on the isolates T. asperelloides TR-356 and Trichoderma spp. 2. With the results obtained, it was possible to conclude that the isolates T. asperelloides TR- 356 and Trichoderma spp. 2 were the most effective in antagonizing the phytopathogen F. oxysporum, making them potential BCAs.