Molecular and phenotypic identification of bacteria from rhizosphere soil with tolerance to Mancozeb fungicide in Manaus, Amazonas State, Brazil

Abstract

The use of fungicides in agriculture has intensified, causing great impact on soil and biota where they are concentrated. The presence of these compounds in the soil has been causing changes in the behavior of microorganisms, which began to acquire strategies to the presence of these products. Mancozeb is a fungicide from the group of carbamates, whose action by contact inactivates the essential enzymes of fungi. The aims of this study were: isolating soil bacteria; characterizing the isolates with biochemical assays and molecular tools; obtaining the isolated growth on minimal medium supplemented with fungicide; establishing a collection of bacteria with bioremediation potential. Bacteria were isolated from isolation techniques in two different culture media: minimal medium and Bushneel Haas medium plus 3.6 gL^-1 of Mancozeb. The identification was performed by phenotypic characterization, using biochemical assays to determine gender and molecular identification by sequencing the 16S region with primers 1492R, 513F, which amplify 1,000 base pairs. Eleven bacterial isolates were identified in four families, four genera and 11 species. The Bacillaceae was the most outstanding family, with 81.81% of the isolates. These tests allowed us to verify the tolerance of bacteria isolated in a higher concentration than used in the field to control pests. The collection of microorganisms from this survey can be used for future studies involving the biodegradation of xenobiotics.