Isolation of Pseudomonas from maize roots

CORDERO, PV.; FISCHER, SE.; CAVIGLIASSO, AM.; MORI, GB.

Huerta Grande - Córdoba

Congreso; Primera Reunión Conjunta de Sociedades de Biología de la República Argentina, XVI Jornadas Científicas de la Sociedad de Biología de Córdoba, IX Jornadas de la Sociedad Argentina de Biología y XXV Reunión Anual de la Sociedad de Biología de Cuyo; 2007

Introduction: Rhizobacteria beneficial to plants are often referred as “Plant-Growth-Promoting Rhizobacteria” (PGPR). Several direct or indirect mechanisms have been postulated to explain how they stimulate plant growth (Lugtenberg et al., 2004). Pseudomonas spp are among the bacteria that can be considered PGPR. The objective of the present study was to isolate Pseudomonas with PGPR ability from maize roots. Methods: Bacterial strains were isolated from the bulk soil, rhizosphere and endorhizosphere of maize plants grown in fields of Cordoba Province, in King B and Gould´s S1 medium. Gram stain and biochemical tests were realized. Isolates were analyzed for their ability to solubilize phosphate, produce siderophore, indole acetic acid (IAA), extracellular enzymes and inhibit fungi phytopathogens. Results: A greater number of isolates was obtained from rhizosphere than endorhizosphere and bulk soil in both King B and Gould´s S1 medium. Plant growth promotion mechanisms were analyzed in isolates that showed phenotypic characteristics of Pseudomonas genus. We observed that some strains have biocontrol and plant growth promotion potential; for example, DKR39 and DKR41 strains were able to solubilize phosphate, synthesize siderophores,proteases and inhibit in vitro Rhizoctonia solani. MGR1 synthesize siderophores, cellulases, solubilize phosphate and inhibit phytopathogens.