Prospecção de isolados bacterianos com produção de substâncias com potencial de controle de plantas daninhas

Abstract

Among the phytosanitary problems commonly occurring in agricultural systems, weed control is the one with the highest consumption of agricultural pesticides. Weeds have mechanisms that allow them to survive, even in adverse situations, competing with cultivated plants for water, light and nutrients. The most commonly used control is carried out with herbicides, however, cases of resistance have already been reported, reducing their efficiency. Therefore, this scenario has led the scientific community to seek new control methods, one of which is biological control, through bioherbicides. The objective of this work was to bioprospect bacterial isolates contained in the collection of the Soil Microbiology and Agricultural Biotechnology laboratory, which produce substances with potential to control germination in the species Capim Amargoso, Capim-de-galinha and Vassourinha de Botão. The first tests, called screening, were conducted in a greenhouse at UFMT-SINOP, where 15 extracts of bacterial isolates were tested. In trays containing sand, 50 seeds were placed, subsequently sprayed with extracts containing bacterial metabolites. The treatments that showed control greater than 50% inhibition of germination (8, CEL 08, CEL 09, 05 UFVD, 09 UFVD, 11 UFVD, 15 UFVD) were subjected to repeated tests. The germination tests had 3 replications for each treatment, and the control. In the germination test, isolate 15 UFVD stood out, reducing the germination of the Vassourinha de Botão species by 100%. To test the effect of the extract on cultivated plants, tests were carried out on Germitest Papers, with Soybean seeds, moistened with the extract of isolate 15 UFVD. After 10 days, it was found that the metabolites of the isolate were capable of releasing substances that inhibited root protrusion of the seed by 33%, and, where protrusion occurred, no elongation of the primary root was identified. With this, it is possible to conclude that the metabolites present in isolate 15 UFVD have the capacity to reduce germination, however, it is necessary to develop new research, so that the bioherbicide can be used, without affecting the crop of interest.