ADAPTIVE PLASTICITY OF BACTERIAL COMMUNITIES IN DIFFERENT ENVIRONMENTS

The demand for higher agricultural productivity increases concomitantly with intensive use of pesticides.The improper use and disposal of the pesticides containers entail environmental problems, such as contamination of soil, air and water. Bacteria of the Pseudomonas genus have mechanisms of resistance and adaptation to chemically stress ful environments. The objective of this work was to evaluate the herbicide tolerance ability by bacteria of same genus. The strains were isolated in agricultural soil of Palotina, Paraná; in water from Verde River and from reservoir facilities used to store water used to wash herbicide containers. These facilities are located at BASF Experimental Station, Capão da Onça Farm School, UEPG, Ponta Grossa, Paraná State. The bacterial strains were stored in the Environmental Microbiology Collection of the Environmental Microbiology Laboratory, UEPG. Growing strains were obtained by incubation in Luria broth (LB: 10 g/L tryptone, 5 g/LNaCl, 5 g/L yeast extract), 30 °C over night. The Pseudomonas strains were selected in the Cetremide medium. After that, tolerant strains were selected in LB medium containing the herbicides Aminol (active principle2,4D), Atectra (dicamba), Roundup (glyphosate), Boral 500 SC (sulfentrazone) and Heat (saflufenacil). This selection was based on growth ability to reachthe optical density greater than 1.0 after 48 hours of incubation. The agricultural soil stock contains 28 herbicide tolerant strains, which 2 was Pseudomonas tolerant to saflufenacil and dicamba, but not tolerant to sulfentrazone and glyphosate; and only 1 tolerant strain to 2,4D. From the reservoir collection, 30 strains were selected, of which 26 are Pseudomonas, with 23 tolerant strains to one herbicide at least. In this collection were characterized 20 strains tolerant to saflufenacil; 15 to sulfentrazone; 6 to glyphosate; 19 for dicamba and 17 for 2,4-D. The stock of Verde River water contains 43 strains, which 22 are Pseudomonas, with 17 tolerant to at least one herbicide. In this collection 13 strains are tolerant to saflufenacil, 12 to sulfentrazone, 5 to glyphosate, 12 to dicamba and 10 to 2,4D.These preliminary data indicate that bacterial isolates, already characterized as strains belonging to the same genus but distinct environments, present responses systems with different fitness strategies. This fitness plasticity will be studied in these groups selected bytheir phylogenetic proximity, and should constitute the research model of the laboratory. This model is aim to search for differential genetic components responsible for the variety of responses to herbicides, even in phylogenetically close genomes.