Natural glufosinate resistance of soil microorganisms and GMO safety

Herbicides are one of the most widely used chemicals in agriculture. While they are known to be harmful to non-target organisms, the effects of herbicides on the composition and functioning of soil microbial communities remain unclear. Here we show that application of three widely used herbicides—glyphosate, glufosinate and dicamba—increase the prevalence of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in soil microbiomes without clear changes in the abundance, diversity and composition of bacterial communities. Mechanistically, these results could be explained by a positive selection for more tolerant genotypes that acquired several mutations in previously well-characterized herbicide and antibiotic resistance genes. Moreover, herbicide exposure increased cell membrane permeability and conjugation frequency of multidrug resistance plasmids, promoting ARG movement between bacteria. A similar pattern was found in agricultural soils across eleven provinces in China, where herbicide application, and the levels of glyphosate residues in soils, were associated with increased ARG and MGE abundances relative to herbicide-free control sites. Together, our results show that herbicide application can enrich ARGs and MGEs by changing the genetic composition of soil microbiomes, potentially contributing to the global antimicrobial resistance problem in agricultural environments.

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“…2021 ). Bacterial tolerance to herbicides is known to vary both between and within species ( Tothova et al. 2010 ; Bote et al.…”

Section: Introductionmentioning

confidence: 99%

Herbicide Selection Promotes Antibiotic Resistance in Soil Microbiomes

Liao

Yang

et al. 2021

Molecular Biology and Evolution

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“…GM crops are considered to be the most rapidly adopted crop in modern times [2]. Nevertheless, scientists were worried about the potential risks of GMOs due to diversification of exogenous gene sources and the unpredictability of biological development [3–6]. The potential risks of GMOs have also received scrutiny from consumers, making assessments of GMOs contained in food and feed more important [5–8].…”

Section: Introductionmentioning

confidence: 99%

High-throughput sequencing analysis of microbial community diversity in response to indica and japonica bar-transgenic rice paddy soils

Zhang

Shen

et al. 2019

PLoS ONE

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Potential environmental risks of genetically modified (GM) crops have raised concerns. To better understand the effect of transgenic rice on the bacterial community in paddy soil, a field experiment was carried out using pairs of rice varieties from two subspecies (indica and japonica) containing bar transgene with herbicide resistance and their parental conventional rice. The 16S rRNA gene of soil genomic DNA from different soil layers at the maturity stage was sequenced using high-throughput sequencing on the Illumina MiSeq platform to explore the microbial community diversity among different rice soils. There were no significant differences in diversity indices between transgenic japonica rice and its sister conventional rice (japonica pair) among different soil layers, but, significant differences was observed between transgenic indica rice and its conventional rice (indica pair) in the topsoil layer around concentrated rice roots according to the ace diversity index. Though the japonica rice soil and indica rice soil were shared several key genera, including Rivibacter, Anaeromyxobacter, Roseomonas, Geobacter, Thiobacillus, Clostridium, and Desulfobulbus, the primary bacterial genera in indica rice soil were different from those in japonica rice. Synechococcus and Dechloromonas were present in japonica rice samples, while Chloronema, Flexibacter, and Blastocatella were observed in indica rice soil. Moreover, the abundance of genera between GM and non-GM varieties in japonica rice was significantly different from indica rice, and several bacterial communities influenced these differences. Anaerovorax was more abundant in transgenic japonica rice soil than conventional rice soil, while it was deficient in transgenic indica rice soil compared to conventional rice soil, and opposite responses to Deferrisoma were in that of indica rice. Thus, we concluded that transgenic indica and japonica rice had different effects on soil bacteria compared with their corresponding sister conventional rice. However, these composition and abundance difference only occurred for a few genera but had no effect on the primary genera and soil characteristics were mainly contributed to these differences. Thus, differences in bacterial community structure can be ignored when evaluating the impacts of transgenic rice in the complex soil microenvironment.

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“…In the first experiment, numbers of colony forming units (CFU) of rhizospheric and soil bacteria were determined on nutrient agar ("BioLife", Italy) without and with 1 mM glufosinate-ammonium ("Sigma-Aldrich", Switzerland). The concentration of glufosinate-ammonium has been estimated as minimum inhibitory for bacteria sensitive to it (Tothova et al, 2010). Since in the first experiment it was estimated that the sensitivity of bacteria to the 1 mM glufosinate-ammonium is low, it was not added to the growing media in the next experiments.…”

Section: Methodsmentioning

confidence: 99%

Impact of barley (Hordeum vulgare L.) transgenic line H228.2A on substrate and rhizosphere microorganisms and the possibility of horizontal gene transfer

Grantina-Ievina

Minova

Rostoks

2013

Zemdirbyste-Agriculture

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Numerous investigations have been carried out to determine the impact of genetically modified plants, such as potato, maize, alfalfa and tobacco, on soil microorganisms and the results are contradictory. We applied classical microbiology methods to study quantitative changes of bacterial and fungal abundance in substrate and rhizosphere from barley (Hordeum vulgare L.) transgenic line H228.2A containing Rpg1 and bar genes, and its parent nontransgenic variety 'Golden Promise'. In addition, molecular biology methods were used to determine, if horizontal gene transfer from barley transgenic line to soil bacteria has occurred under experimental conditions by screening bacterial genomes for the presence of Rpg1 gene sequences using polymerase chain reactions. Results did not show significant impact on substrate and rhizosphere microorganisms. In the second pot experiment the average number of filamentous fungi in the rhizosphere of parent line 'Golden Promise' was higher than in the rhizosphere of transgenic line, but the variation among samples was very high probably caused by the high variation of substrate moisture content. None of bacterial deoxyribonucleic acid (DNA) samples isolated from substrate of rhizosphere of barley transgenic line resulted in positive amplification of Rpg1 gene-specific primer product.

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Natural glufosinate resistance of soil microorganisms and GMO safety

Cited by 6 publications

References 40 publications

Herbicide Selection Promotes Antibiotic Resistance in Soil Microbiomes

Herbicide Selection Promotes Antibiotic Resistance in Soil Microbiomes

High-throughput sequencing analysis of microbial community diversity in response to indica and japonica bar-transgenic rice paddy soils

Impact of barley (Hordeum vulgare L.) transgenic line H228.2A on substrate and rhizosphere microorganisms and the possibility of horizontal gene transfer

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