Resumen

HERNANDEZ GUIJARRO, Keren; COVACEVICH, Fernanda; APARICIO, Virginia Carolina  y  DE GERONIMO, Eduardo. Soil native bacteria as potential degraders of glyphosate herbicide and plant growth promoters. Cienc. suelo [online]. 2018, vol.36, n.2, pp.105-114. ISSN 1850-2067.

The use of microorganisms and their beneficial interaction with plants and the ecosystem, is a promising strategy to achieve a sustainable agriculture. Since glyphosate is present at high frequency at agricultural soils in Argentina, mainly at the Pampean region, and its negative impact on some beneficial soil microorganisms has been reported, the aims of this work were i) to isolate and characterize soil phosphorous-solubilizing bacteria with the capacity to tolerate/degrade glyphosate, and ii) to evaluate their potential as growth-promoter in a trial with maize hybrid plants. A total of 9 bacterial strains were isolated, from both an agricultural and a pristine soil near Balcarce (Buenos Aires, Argentina), solubilizing phosphate in a range of 249 - 973 μg mL^-1 of soluble-P on tricalcium phosphate medium. Three of these strains (named P1, A2 and P12), could grow on media containing glyphosate as the sole phosphorus source. P12 strain decreased in 30% the initial glyphosate concentration after 72 hours. The strains were identified as Enterobacteriae by partial 16S rDNA sequencing, belonging to Pantoea and Enterobacter genera. An inoculation trial, using as substrate two different soils from Buenos Aires province - Arroyo Corto and Líbano- showed that A2 and P12 strains produced significant increases in the dry and fresh matter of maize plants, respectively. These strains are promising as bio-inoculants and further studies will be necessary to enhance their functions in field inoculations. This work constitutes the first report of glyphosate-degrading Enterobacteria isolated from Argentine soils.

Palabras clave : Biofertilizers; P-solubilizing bacteria; PGPR; remediation.

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