Bacterial community profiling in the rhizosphere of field grown GM and non-GM maize

Abstract

This study examined the impact of genetically modified corn on bacterial functional community in the rhizosphere. Rhizospheric soil samples from GM and non-GM corn were collected at 30 days after sowing (DAS) and at post-harvest from two experimental fields in Gauteng, South Africa. Plate count results obtained on Pseudomonas selective media indicated 1.5 × 103 cfu in GM and 1.7 × 103 cfu in non-GM soil samples at 30 DAS. At post-harvest, there was 80% decline in the rhizobacteria population in GM sample and 76% in the non-GM. To compare bacterial functional community in GM and non-GM soil, Biolog GN2 microplate, a sole carbon substrate utilization profile, was used and no significant difference was observed. Based on analytical profile index identification system, species of Pseudomonas putida, P. stutzeri and Achromobacter denitrificans were identified in GM and non-GM at 30 DAS. No Pseudomonas species was identified in samples at post-harvest. These findings are of great significance with regards to the investigation of possible impact of GM maize on bacterial functional community in the rhizosphere.