Induced resistance in the biocontrol of Sclerotium rolfsii by a PGPR

ANA LAURA FURLAN, MARÍA LAURA TONELLI, TANIA TAURIAN, ADRIANA FABRA, STELLA CASTRO.

Villa Carlos Paz, Córdoba, Argentina

Congreso; SAIB; 2008

Plant growth promoting rhizobacteria (PGPR) are colonizing bacteria with beneficial effects including plant growth promotion and disease control such as the induction of systemic resistance (ISR). In the present study, the enzymatic activities of phenylalanine ammonia-lyase (PAL), peroxidase (PO) and â 1-3 glucanase were evaluated in roots and leaves from peanut plants inoculated with the PGPR bacteria SEHEP2 and with the fungal pathogen Sclerotium rolfsii. SEHEP2 is an epiphytic bacteria isolated from peanut leaves. In order to test its ability to induce ISR, peanut plants growing in Hoagland solid medium were inoculated with SEHEP2 strain in their leaves and the fungal pathogenic S. rolfsii in the culture medium. Twenty two days after planting, the enzyme activities were analyzed in four treatments: control; SEHEP2; S. rolfsii; SEHEP2 and S. rolfsii. The higher specific activity of PAL and â 1-3 glucanase were founded in the leaves of plants treated with both SEHEP2 and S. rolfsii. In contrast, the enzyme PO showed a significant increase in plants coinoculated with SEHEP2 and S. rolfsii in relation to those inoculated only with S. rolfsii.  We speculate that plant defense enzymes are stimulated in peanut plants by this PGPR bacterium  with ISR property.