Effect of pesticides application on peanut (Arachis hypogaea L.) associated phosphate solubilizing soil bacteria

Abstract

In the peanut-growing area of Córdoba, Argentina, herbicides and fungicides utilization is a common practice. This study analyses the effect of pesticides applied at recommended rates on the number and diversity of phosphate solubilizing soil bacteria from this area and the frequency of pyrroquinoline quinone genes (. pqq). Pesticide soil treatment did not affect the abundance of culturable phosphate solubilizing bacteria but increased their genetic diversity and altered the frequency of pqqE and pqqC genes. The presence of the pqqE and pqqC genes was observed in a high percentage of isolated Gram-negative phosphate solubilizing bacteria. The analysis of the diversity of 16S rDNA and pqqE genes of soil DNA samples indicated a higher diversity in pesticides treated soil samples compared to control soil samples. Results obtained indicated that pesticides application increases diversity of soil bacterial community and therefore phosphate solubilizing soil bacterial population probably as a result of an increase of bacterial populations that use pesticides applied as carbon and energy source. Analysis of pqq genes frequency and diversity suggested that they would be potential molecular marker of Gram-negative phosphate solubilizing soil bacteria.