Cadaverine production by Azospirillum brasilense and its possible role in plant growth promotion and osmotic stress mitigation.

FABRICIO CASSÁN; SANTIAGO MAIALE; OSCAR MASCIARELLI; ALFONSO VIDAL; VIRGINIA LUNA AND OSCAR RUIZ

EUROPEAN JOURNAL OF SOIL BIOLOGY

Elsevier

Lugar: Amsterdam-London-Berlin; Año: 2009 vol. 45 p. 12 - 19

1164-5563

Polyamines are considered plant growth regulators compounds among them; cadaverine has been correlated with root growth promotion or osmotic stress mitigation in plants. The aim of this work was to evaluate the A. brasilense capacity to produce cadaverine in chemically defined medium and inoculated rice seedlings, and to correlate this capability with a plant growth promotion or osmotic stress alleviation in hydroponics cultures. To prove this, A. brasilense Az39 aerobically was cultivated at 30 C° and 80 rpm in chemically defined NFb or NFb supplemented with L-lysine medium. Cadaverine was identified and quantified by dansyl-derivated method employing a fluorescence-HPLC system, and lysine decarboxilase (LDC) activity was determinate by 14CO2 production in a closed tube system feeded with [14C]-lysine. Rice (Oryza sativa L.) cv. El Paso 144 seedlings were inoculated and cultured in hydroponic systems under optimal or osmotic stress conditions at of -0.47 and -0.82 MPa water potentials, plus 1 nM and 1µM addition of exogenous cadaverine solution respectably. In optimal conditions, plant growth parameters, cadaverine production and LDC activity were evaluated, while in osmotic stress growth parameters and ABA production were analyzed. Our results show that A. brasilense Az39 induce a root growth promotion and collaborates to mitigate the osmotic stress in inoculated rice seedlings, partly due to cadaverine production.