Impact of long-term cropping of glyphosate-resistant transgenic soybean [Glycine max (L.) Merr.] on soil microbiome

Abstract

The transgenic soybean [Glycine max (L.) Merrill] occupies about 80 % of the global area cropped with this legume, the majority comprising the glyphosate-resistant trait (Roundup Ready(®), GR or RR). However, concerns about possible impacts of transgenic crops on soil microbial communities are often raised. We investigated soil chemical, physical and microbiological properties, and grain yields in long-term field trials involving conventional and nearly isogenic RR transgenic genotypes. The trials were performed at two locations in Brazil, with different edaphoclimatic conditions. Large differences in physical, chemical and classic microbiological parameters (microbial biomass of C and N, basal respiration), as well as in grain production were observed between the sites. Some phyla (Proteobacteria, Actinobacteria, Acidobacteria), classes (Alphaproteobacteria, Actinomycetales, Solibacteres) and orders (Rhizobiales, Burkholderiales, Myxococcales, Pseudomonadales), as well as some functional subsystems (clustering-based subsystems, carbohydrates, amino acids and protein metabolism) were, in general, abundant in all treatments. However, bioindicators related to superior soil fertility and physical properties at Londrina were identified, among them a higher ratio of Proteobacteria:Acidobacteria. Regarding the transgene, the metagenomics showed differences in microbial taxonomic and functional abundances, but lower in magnitude than differences observed between the sites. Besides the site-specific differences, Proteobacteria, Firmicutes and Chlorophyta were higher in the transgenic treatment, as well as sequences related to protein metabolism, cell division and cycle. Although confirming effects of the transgenic trait on soil microbiome, no differences were recorded in grain yields, probably due to the buffering capacity associated with the high taxonomic and functional microbial diversity observed in all treatments.

Metagenome-Wide Association Study and Machine Learning Prediction of Bulk Soil Microbiome and Crop Productivity

“…On the other hand, biotic features such as pathogen, pest (Hartman et al, 2015), and beneficial symbiosis such as root nodulation (Tkacz and Poole, 2015) are also involved in yield performance. Moreover, an important biotic feature is the genetics of the crop variety (the genotype), which includes the genetics of the photosynthesis and productivity performance (Dhanapal et al, 2016; Li et al, 2016), the genetics of water and nitrogen utilizing efficiency (Dhanapal et al, 2015; Chen et al, 2016), the genetics of disease and pest resistance (Chang et al, 2016; Revelle, 2016), and the genetic influence on structuring the rhizosphere microbiome (Jin et al, 2009; Babujia et al, 2016; de Almeida Lopes et al, 2016). In our study, we discovered additional factors underlying crop productivity when the above factors were identical or similar.…”

Effects of an EPSPS-transgenic soybean line ZUTS31 on root-associated bacterial communities during field growth

“…napus variety Excel. The composition of rhizosphere microbial communities of the herbicide-tolerant transgenic Zoysia grass differs from that of its nontransgenic Zoysia grass [ 23 ].The glyphosate-resistant transgenic soybean line BRS 245 RR affects soil microbial taxonomic and functional abundances compared with its parental conventional soybean cultivar BRS 133 [ 24 ]. The glyphosate-tolerant transgenic soybean line NZL06-968 significantly impacts the phylogenetic diversity of rhizosphere microbial communities compared with its control cultivar Mengdou12 [ 25 ].…”

Agricultural Pollution Risks Influence Microbial Ecology in Honghu Lake

“…As to biomarkers in sediment samples from impacted sites, these included members of the Hydrogenophaga genus, belonging to Burkholderiales (Class Betaproteobacteria) , which have been previously associated with agricultural activities(Babujia et al 2016). Moreover, members of the genus Pseudomonas , belonging to family Pseudomonadaceae , can play an important role in agricultural ecosystems, particularly those associated with plant growth-promotion and disease suppression were mentioned(Pesaro and Widmer 2006).…”