Potencial de fungos isolados da área de mineração para biocontrole de fitopatògenos de soja

Abstract

Although the use of synthetic fungicides is the main way to control phytopathogenic fungi, they can have a toxic potential to human health and the environment. Thus, biological control has been used as a strategy to minimize the damage caused by phytopathogenic fungi in plants. Therefore, fungi isolated from the mining area (R21B1 and R22A3) are being studied so that they can be applied to the control of plant diseases, which can be more efficient and less dangerous to the environment. Thus, the objective of the present study was to evaluate the effect of R21B1 and R22A3 isolates as potential antagonists on the phytopathogens Fusarium solani and Macrophomina phaseolina under in vitro conditions. The analyses were carried out in triplicates with daily observations for seven days. For the tests performed, the Grid was used for mycelial growth counting, in vitro culture pairing test and volatile metabolite test. To calculate the percentage of mycelial growth inhibition, the following formula was applied: % inhibition = [(crConfrontation)/control)] x 100, for the analysis of volatiles, the percentage (%) inhibition = [(crCvolatiles)/control)] x 100 was used. In the in vitro culture pairing test, the fungal isolates R21B1 and R22A3 showed an inhibition percentage of 67.8% for the phytopathogen Fusarium solani, and for Macrophomina phaseolina they showed 72.64% and 72.2% of inhibition, respectively. For the volatile metabolites test, only Fusarium solani showed inhibition for the fungi R21B1 72.64% and R22A3 72.16%, while for the fungus Macrophomina phaseolina it did not show inhibition. The analysis of the micro-extracts did not present consistent results and it was necessary to redo the analyzes at new wavelengths to obtain concrete results.Thus, the results found in this work stimulate, in addition to laboratory tests, the continuation of further studies of these isolates, in order to verify their efficiency in the in vivo control of plant diseases.