Characterization of peanut rhizobia with PGPR activities

TAURIAN, T., AGUILAR, O.M., FABRA, A.

Villa Giardino, Córdoba

Jornada; XV Jornadas Científicas de la Sociedad de Biología de Córdoba; 2005

Sociedad de Biología de Córdoba

Abstract Arachis hypogaea L. (peanut) is an important crop all over the world that provides food for direct human subsistence and other several food products. Argentina is one of the major peanut producers in the world, and about 94% of its production takes place  in the province of Córdoba. The increase in the yield of some leguminous plants inoculated with selected rhizobia strains has been associated with the rhizobia ability to act as plant growth promoting rhizobacteria (PGPR). Like other PGPR, rhizobia are able to solubilize phosphate, produce siderophores, cyanides and show antagonistic activity against phytopathogen fungi. Because of their adaptation to the ecological conditions from a local soil, the native strains are preferentially used to inoculate a determinate area. Objetive: To select PGPR native peanut rhizobia from Cordoba soils. Methods: Phosphate solubilization (Frioni, 1999), Siderophore production (Schwyn y Neilands, 1987), Indol acetic acid production (AIA) (Glickmann y Dessaux, 1995), Antagonistic activity (March y Marinelli, 1997). Results and Discussion: It was possible to observe that in the 14 rhizobia isolates analyzed the 57% showed ability to solubilize phosphate and siderophores and 33% demonstrated to produce AIA. Antagonistic activity was observed between the isolates against the peanut pathogen fungi Sclerotinia minor and S. sclerotiorum (57 and 43%, respectivelly). The present study show that peanut soils of the province of Cordoba harbor rhizobacteria with important PGPR properties. These bacteria represent a potential source for inoculation practices in agriculture.