EFFECT OF AGROCHEMICAL APPLICATION ON PEANUT (Arachis hypogaea L.) ASSOCIATED PHOSPHATE SOLUBILIZING SOIL BACTERIA

ANZUAY, MARIA SOLEDAD; ANGELINI, JG, FABRA, A, TAURIAN, TANIA

Avances en estudios básicos y aplicados sobre PGPR en Latinoamérica pgpr latinoamerica 2014

Claudio Valverde Editor

Año: 2014; p. 88 - 93

In the peanut production area of Córdoba, Argentina, herbicides and fungicides application is a common practice. This study analyses the effect of agrochemicals application on soil phosphate solubilizing bacteria associated to this legume in the province of Córdoba. The main mechanism of mineral phosphate-solubilization by microorganisms is associated with the production of low-molecular-weight organic acids, mainly gluconic and 2-cetogluconic acids. These acids are produced in the periplasm of many Gram-negative bacteria through a non-phosphorylated direct oxidation pathway of glucose. The glucose dehydrogenase requires the cofactor redox pirroquinolin quinine (PQQ), whose biosynthesis involves a PQQ operon. The role of PQQ has been described to be essential for the phosphate solubilizing phenotype in several bacteria. In this study, pqqE gene was selected as molecular marker to study the effect of agrochemicals on soil phosphate solubilizing bacterial population from the peanut producing area. Bacterial DNA was extracted from soil samples of treated and control plots and used as template for pqqE-PCR. The expected amplification product was used to construct a pqqE clone library. There were obtained 72 clones (37 clones from treated soil samples and 35 from control soil samples). RFLP-pqqE analysis indicated an increase in the diversity of the sequence of this gene in clones obtained of treated plot.