Glyphosate vulnerability explains changes in root-symbionts propagules viability in pampean grasslands

Abstract

Research into the impact of agricultural practices on plant symbionts is essential for understanding the factors that modulate plant community productivity and diversity. Although glyphosate is used worldwide as an herbicide, its effects on root symbionts under natural conditions have not been sufficiently studied. We performed a field experiment to evaluate the influence of glyphosate, used for promoting winter forage production, on the viability of arbuscular mycorrhizal fungi (AMF) and rhizobium propagules and other ecosystem traits in native grasslands. The number of viable propagules was strongly reduced with a single application at the recommended dose. Spore viability reduction was dependent on AMF species. Furthermore, changes in plant community composition and soil salinity were detected, which may eventually influence these symbionts in the future. Considering the low nutrient availability and high root-symbiont dependency of several species with forage value, repeated applications might lead to a loss in the grassland diversity and productivity, decreasing livestock production. Application of sublethal doses of this herbicide could avoid these damages, although success in increasing winter forage production would be less. Our results are relevant for understanding the effects of glyphosate on non-target species and designing sustainable land management systems.2014 Elsevier B.V. All rights reserved.

Arbuscular mycorrhizal fungi and their response to pesticides

“…In grasslands, a clear species‐specific effect was also shown. Whereas the spore viability of F. mosseae and C. etunicatum was similar in all treatments, the spore viability of F. caledonium and F. constrictum was reduced in glyphosate‐treated (field rate) plots . This result reflects the different sensibilities of certain AMF strains, which have also been shown for different soil tillage and management practices …”

Glyphosate-Induced Specific and Widespread Perturbations in the Metabolome of Soil Pseudomonas Species

“…There have been numerous reports of adverse effects of glyphosate treatments on various microbial species and communities (Lévesque et al, 1987;Larson et al, 2006;Kremer and Means, 2009;Zobiole et al, 2011;Lane et al, 2012;Druille et al, 2013Druille et al, , 2015. Here we seek to gain insights into the intracellular targets underlying the response of soil Pseudomonas species, such as P. putida, P. fluorescens, and P. protegens, to glyphosate exposure.…”

Estudio de las comunidades de hongos formadores de micorrizas arbusculares en soja: relación con la nutrición fosforada en agroecosistemas

“…M.Sc. Valeria S Faggioli producción de soja, tales como el uso de pesticidas y la fertilización, las cuales afectan negativamente a ciertas especies de Glomeromyota (Druille et al, 2015;Schalamuk et al, 2006). Posiblemente, ante reiterados ciclos de cultivo, la abundancia de estos hongos en el suelo luego de la cosecha sea una ventaja al momento de infectar raíces de la campaña siguiente.…”

“…Por ejemplo, la masiva adopción de la siembra directa desde los '90s, ha conservado las redes hifales y propágulos de HFMA (Schalamuk et al, 2009). Al mismo tiempo, el uso generalizado de glifosato podría estar afectando de manera directa e indirecta a las comunidades de HFMA (Druille et al, 2015). Por otra parte, la sustitución de una comunidad vegetal diversa como las pasturas y flora autóctona por una especie de escasa rotación con otros cultivos es un factor potencialmente perjudicial para la diversidad de HFMA.…”