Antibiose e consórcio de cepas de Bacillus contra isolados de Fusarium oxysporum f. sp. cubense

Abstract

The banana is one of the most consumed fruits in the world, with enormous nutritional and economic importance. However, during its cycle, banana cultivation is affected by various diseases, with Panama disease standing out as one of the greatest global threats to banana crops. This disease is caused by the fungus Fusarium oxysporum f. sp. cubense (Foc). Sustainable alternatives, such as the use of biological control agents, have been explored to contain this phytopathogen. Among the microorganisms used in studies on pathogen control, bacteria of the Bacillus genus stand out. In this study, the objective was to evaluate the antibiosis and consortium of Bacillus strains against Foc isolates to enable in vivo studies on the use of bacterial mixtures for the control of Panama disease. To this end, thirty-one Bacillus isolates were subjected to antibiosis testing against two fungal isolates of the pathogen, RFB65 and RFB86, to assess their antagonistic activity. Subsequently, among the thirty-one bacterial strains, seven were selected based on their ability to inhibit fungal growth for in vitro compatibility tests. All bacterial strains demonstrated potential to inhibit the mycelial growth of fungal isolates when compared to the control treatment. However, strains LPPC259, LPPC266, LPPC283, and LPPC265 stood out, showing the highest inhibition percentages, with 77.41%, 73.40%, 66.24%, and 61.92% against isolate RFB65, respectively. Regarding isolate RFB86, the inhibition percentages were 79.40% for LPPC283 and 75.67% for LPPC259, while LPPC265 and LPPC266 showed inhibition rates of 70.40% and 67.93%, respectively. Five of the seven strains tested in the in vitro compatibility assay showed no halos, indicating they are compatible. It was concluded that Bacillus strains inhibited the in vitro mycelial growth of Foc isolates and demonstrated compatibility with each other for future use in in vivo studies on the control of Panama disease in banana plants.