An integral study of native-PGPR tp improve plant growth in soils affected by environmental stress

FISCHER, S.; ALVAREZ, F; PRINCIPE, A.; CASTRO, M.; JOFRÉ, E.; MORI, G.

Rosario

Congreso; XLII Reunión anual de SAIB; 2006

SAIB

We have selected strains from saline soils of Cordoba province able to promote the growth of different plants. These isolates belong to Pseudomonas, Ochrobactrum, and Bacillus genus. In order to advance on the characterization of these strains different strategies were applied: Survival of Pseudomonas sp. SF 4C in different soils: The viable cell number was determined at 15, 30 and 60 days post-inoculation in the rhizosphere and bulk soil. This strain was able to survive in the wheat rhizosphere in both tested soils along this experiment, while in the bulk soil the survival at 60 days was only observed in the nonfertilized soil. Identification of functions localized on a megaplasmid of Ochrobactrum sp. 11a: the megaplasmid was mobilized to A. tumefasciens free-plasmid UBAPF2. The selected A. tumefasciens UBAPF2 transconjugants showed the same resistance to heavy metal than Ochrobactrum sp. 11a and the presence of this plasmid was confirmed by Eckhardt. Partial characterization of metabolites associated to biocontrol of phytopathogen fungy. Supernatans obtained from Bacillus sp. cultures showed antifungal activity in vitro against several species of Fusarium and Sclerotinia genus. The supernatants were analyzed by reversed-phase HPLC. Peaks were fractionated and examined against Sclerotinia sclerotiorum on APD. Some of these fractions showed antifungal activity