Volatile organic compounds produced by native fluorescent Pseudomonas improves essential oils in Mentha piperita L.

SANTORO, M., BOGINO, P., GIORDANO, W., BANCHIO, E.

Huerta Grande, Córdoba

Congreso; 2nd Meeting of the Latin American Association of Chemical Ecology (ALAEQ).; 2012

Some bacteria, including fluorescent Pseudomonas, live in the rhizophere and promote plant growth. In the present work, fluorescent Pseudomonas were isolated from rhizospheric soil of a comercial crope of Mentha piperita L located in Villa Dolores, Córdoba. Explants of Mentha piperita L were exposed to volatile organic compound (VOCs) produced by these native bacteria. The aim of this work was to determinate if VOCs emitted by bacteria affects the production or composition of essential oil (EO) in Mentha piperita L. A total of 40 bacterial strains were tested of which only 11 strains produced an increase in plant growth parameters. In this sense, shoot fresh weight of plants exposed to bacterial VOCs was increased 3 to 4.5 folds relative to control, plants exposed to distilled water. These plant growth promoting strains were further studied and selected for the analysis of EO. Gas chromatography was used to determinate qualitatively and quantitatively the composition of monoterpenes. Plants exposed to VOCs of SJ25 and SJ27 strains displayed a significant increase (p<0,05) in total content of EO, relative to control. The amount of limonene was increased in plant subjected to VOCS of SJ04, SJ28, SJ7b and SJ48 strains, whereas that the amount of menthol and menthyl acetate was increased in plants exposed only to VOCs of SJ04 and SJ7b strains, respectively. All strains displayed a descreasement in content of menthofurane. No significant variations in the content of de menthone, terpineol, pulegone and menthofurarone were observed. The sequences of nucleotide of 16S RNAr gene were analyzed on these strains in order to establish their identity and taxonomic position in a phylogenetic tree constructed with fluorescent Pseudomonas used as reference. We conclude that some native fluorescent Pseudomonads are able to improve the production of essential oils in micropropagated Mentha, even when knowledge of plant promoting-growth activity of VOCs and its mechanism of action are very poor.