Rhizosphere Microbiome and Nutrient Fluxes Reveal Subtle Biosafety Signals in Transgenic Cotton

Genetically modified crops have transformed agriculture, but their long-term ecological impacts remain incompletely understood. Here we investigate how herbicide-tolerant transgenic cotton affects rhizosphere microbial communities and nutrient cycling over a 28-day growth period using 16S rRNA amplicon sequencing and multivariate analyses. We sampled rhizosphere soil from greenhouse-grown transgenic and wild-type cotton plants at five time points, analyzing microbial diversity, community structure, and nutrient dynamics. Despite initial concerns about transgenic modifications disrupting soil ecosystems, we found no significant differences in microbial α-diversity or β-diversity between genotypes. Only minor, transient changes occurred at the genus level, including <5% shifts in <i>Flavobacterium</i> and <i>Ramlibacter</i> abundance on day 14, alongside brief nutrient flux variations that normalized by day 28. Notably, transgenic plants showed enhanced above-ground biomass accumulation without compromising rhizosphere stability or soil moisture content. These results demonstrate that herbicide-tolerant cotton maintains rhizosphere homeostasis while improving agronomic performance, supporting the environmental safety of this biotechnology for sustainable agricultural intensification.