ISOLATION OF INDIGENOUS SOIL MICROORGANISMS SCREENING FOR CHARACTERISTICS POTENTIALLY INDUCING PLANT GROWTH PROMOTING EFFECTS

LEON M; YARYURA P; MONTECCHIA M; HERNANDEZ A; CORREA O; PUCHEU N; KERBER N; GARCÍA A

RESEARCH IN MICROBIOLOGY

Elsevier

Lugar: Francia; Año: 2006

0923-2508

ENVIADO NOVIEMBRE 2006-EN REVISION/Plant growth promotion effects are displayed by single bacterial isolates or by combinations of several microorganisms. These effects are most important in the commercial production of inoculants. We isolated a series of Gram negative and positive strains displaying one or more characteristics which qualified them as potential plant growth promoting bacteria. We used soybean as model crop plant for our tests and selected eight bacterial strains with strong antifungal capacity. This property is important because, added to their positive effects on growth; the isolates would also behave as inhibitors of fungal growth. We measured enzymatic lytic activities (chitinolysis, proteolysis and cellulolysis); production of volatile compounds, biosurfactants, and auxins and also phosphate solubilizing activities. In addition we present a description of the pathogenic activity of the isolates against soybean growth and also against other bacteria present in the rhizosphere and our own isolates. We also inoculated soybean plants using dual mixtures of Bradyrhizobium japonicum with some of our isolates and found that no noticeable effects were detected although a significant increase in the number and/or dry weight of nodules were produced by two of the isolates, a property which is important to be displayed by a soybean inoculant.