Effect of transgenic soybean on functional groups of microorganisms in the rhizosphere in soil microcosm

Neglected Glyphosate-resistant (GR) crops are common in agro-ecosystems mainly due to its benefits of weed management. However, the effect of GR crops on soil ecosystem and on non-target soil organisms need to be monitored. The effect of two transgenic soybeans GR on soil microorganisms, soil enzymes, microbial biomass and plant growth were evaluated. The experimental design was conducted as factorial arrangement with two GR soybean varieties, the Londrina (RR 59) and its near isogenic non-GM 59 Londrina called VAR 1; the second was Valiosa soybean (RR Conquista) and its near isogenic non-GM Conquista - Uberaba soybean called VAR 2. The plants were inoculated with arbuscular mycorrhiza fungi and rhizobia. The results showed that significant differences were observed among GM plants and their parental non-GM only for N biomass, AM colonization and cellulase activity. The presence of AM fungi had great influence on the functional groups of microorganisms while some enzymes activity decreased.