Differential Assembly and Shifts of the Rhizosphere Bacterial Community by a Dual Transgenic Glyphosate-Tolerant Soybean Line with and without Glyphosate Application

Modern agriculture has gained significant economic benefits worldwide with the use of genetically modified (GM) technologies. While GM crops provide convenience to humans, their biosafety has attracted increasing concern. In this study, the Illumina MiSeq was used to perform a high-throughput sequencing of the V3-V4 hypervariable regions of 16S rRNA gene (16S rDNA) amplicons to compare the rhizosphere bacterial communities of the EPSPS/GAT dual transgenic glyphosate-tolerant soybean line Z106, its recipient variety ZH10, and Z106 with glyphosate application (Z106G) during flowering, seed filling, and maturing stages under field settings. At each of the three stages, the alpha and beta diversity of rhizosphere bacterial communities revealed no significant differences between ZH10, Z106, and Z106G. However, some bacterial taxa demonstrated a greater proportional contribution, particularly the nitrogen-fixing rhizobium Ensifer fredii, in the rhizospheric soil of Z106 at the seed filling and maturing stages, when compared to ZH10 and Z106G. The present study therefore suggests that the EPSPS/GAT dual transgenic line Z106 and exogenous glyphosate application have a minimal effect on the composition of the soybean rhizosphere bacterial community but have no impact on the structure of the rhizosphere microbial community during a single planting season.