Background: The worldwide use of glyphosate has dramatically increased, but also has
been raising concern over its impact on mineral nutrition, plant pathogen, and soil microbiota. To date,
the bulk of previous studies still have shown different results on the effect of glyphosate application
on soil rhizosphere microbial communities.
Objective: This study aimed to clarify whether glyphosate has impact on nitrogen-fixation, pathogen
or disease suppression, and rhizosphere microbial community of a soybean EPSPS-transgenic line
ZUTS31 in one growth season.
Method: Comparative analysis of the soil rhizosphere microbial communities was performed by 16S
rRNA gene amplicons sequencing and shotgun metagenome sequencing analysis between the soybean
line ZUTS31 foliar sprayed with diluted glyphosate solution and those sprayed with water only in
Results : There were no significant differences of alpha diversity but with small and insignificant difference
of beta diversity of soybean rhizosphere bacteria after glyphosate treatment. The significantly
enriched Gene Ontology (GO) terms were cellular, metabolic, and single-organism of biological process
together with binding, catalytic activity of molecular function. The hits and gene abundances of
some functional genes being involved in Plant Growth-Promoting Traits (PGPT), especially most of
nitrogen fixation genes, significantly decreased in the rhizosphere after glyphosate treatment.
Conclusion: Our present study indicated that the formulation of glyphosate-isopropylamine salt did
not significantly affect the alpha and beta diversity of the rhizobacterial community of the soybean
line ZUTS31, whereas it significantly influenced some functional genes involved in PGPT in the rhizosphere
during the single growth season.