| Congresso Brasileiro de Microbiologia 2023 | Resumo: 129-1 | ||||
Resumo:The negative consequences of unbridled human activities in different ecosystems are increasingly noticeable. Therefore, nations must adopt collaborative practices to allow sustainable development. In agriculture practices, agrochemicals are a usual choice to control plagues like insects, invasive plants, and microorganisms. However, normally, these are toxic chemicals, and their widespread usage is dangerous to the organisms and ecosystems. The present study aims to investigate biotechnological alternatives to control phytopathogenic fungi using endophytic microorganisms and their secondary metabolites. Thus, the antagonistic activities of five endophytic fungi isolated from Brazil native plant Guarea kunthiana A. Juss. (Meliaceae), were evaluated against the phytopathogenic fungi Sclerotinia sclerotiorum, which affects more than 400 host plants, including soybeans, cotton and beans. The tests were conducted in duplicate using 90 mm Petri dishes containing 20 g.L-1 malt extract and 10 g.L-1 agar. One 8.0 mm diameter disc containing mycelium of the endophytic fungus was placed at one side of the plate, while another side, the disc of the same size containing S. sclerotiorum mycelium. Plates were prepared for each of the five endophytes, separately and were incubated for seven days at 28°C in a BOD oven. To measure the percentage of growth inhibition of S. sclerotiorum, ImageJ software was used and applied the formula: I = (GC-GT)/GC x 100, where I = percentage of inhibition; GC = growth area of the phytopathogenic fungus in the control; GT = growth area of the phytopathogenic fungus in the treatment. We also evaluated the formation of inhibition halos and used a millimeter rule to measure each one of them. Notably, isolates GK A3.5, GK A3.15 and GK A3.8 showed clear inhibition halos, of 8.0 mm, 6.5 mm and 5.5 mm, respectively, which may be indicative of inhibition by antibiosis. They also were particularly effective in reducing the growth of the phytopathogen, exhibiting inhibition percentage of 50,4%, 41,5% and 59,3%, respectively. Furthermore, the isolates GK B1.3 and GK C4.2.1 did not show an inhibition halo. These results suggest that these diverse endophytic isolates from G. kunthiana have potential for studies of their biomolecules, which may lead to the development of new methods for the control of S. sclerotiorum, as an alternative to agrochemicals, which could help to promote sustainable development. Palavras-chave: agriculture, biological control, endophytic fungi, Sclerotinia sclerotiorum, sustainable development Agência de fomento:Fundação Araucária de Desenvolvimento Científico e Tecnológico do Estado do Paraná (FA) | |||||