Data_Sheet_1_Effect of glyphosate, its metabolite AMPA, and the glyphosate formulation Roundup® on brown trout (Salmo trutta f. fario) gut microbiome diversity.docx

Glyphosate is used worldwide as a compound of pesticides and is detectable in many environmental compartments. It enters water bodies primarily through drift from agricultural areas so that aquatic organisms are exposed to this chemical, especially after rain events. Glyphosate is advertised and sold as a highly specific herbicide, which interacts with the EPSP synthase, an enzyme of the shikimate metabolism, resulting in inhibition of the synthesis of vital aromatic amino acids. However, not only plants but also bacteria can possess this enzyme so that influences of glyphosate on the microbiomes of exposed organisms cannot be excluded. Those influences may result in subtle and long-term effects, e.g., disturbance of the symbiotic interactions of bionts with microorganisms of their microbiomes. Mechanisms how the transformation product aminomethylphosphonic acid (AMPA) of glyphosate might interfere in this context have not understood so far. In the present study, molecular biological fingerprinting methods showed concentration-dependent effects of glyphosate and AMPA on fish microbiomes. In addition, age-dependent differences in the composition of the microbiomes regarding abundance and diversity were detected. Furthermore, the effect of exposure to glyphosate and AMPA was investigated for several fish pathogens of gut microbiomes in terms of their gene expression of virulence factors associated with pathogenicity. In vitro transcriptome analysis with the fish pathogen Yersinia ruckeri revealed that it is questionable whether the observed effect on the microbiome is caused by the intended mode of action of glyphosate, such as the inhibition of EPSP synthase activity.

草甘膦（Glyphosate）作为农药复合物在全球范围内被广泛使用，并可在多种环境介质中被检出。其主要通过农业区域的药液飘移进入水体，致使水生生物暴露于该化学物质中，降雨事件后尤为明显。草甘膦作为一种高特异性除草剂被推广和销售，其可与莽草酸代谢途径中的关键酶——EPSP合酶（EPSP synthase）结合，进而抑制生命必需的芳香族氨基酸的合成。然而，不仅植物，细菌也可携带该酶，因此无法排除草甘膦对暴露生物的微生物组产生影响的可能性。此类影响可能引发细微且长期的效应，例如扰乱共生体与其微生物组内微生物之间的共生相互作用。截至目前，草甘膦的代谢产物氨甲基膦酸（AMPA）在此类场景中可能产生干扰的具体机制仍未阐明。本研究采用分子生物学指纹图谱法，证实了草甘膦与AMPA对鱼类微生物组具有浓度依赖性影响。此外，研究还检测到鱼类微生物组的组成在丰度与多样性层面存在年龄依赖性差异。此外，本研究针对肠道微生物组中的数种鱼类病原菌，就其与致病性相关的毒力因子基因表达情况，探究了草甘膦与AMPA暴露产生的影响。针对鱼类病原菌鲁氏耶尔森菌（Yersinia ruckeri）开展的体外转录组分析显示：此前观测到的对微生物组的影响，是否由草甘膦的预期作用模式（如抑制EPSP合酶活性）所引发，仍有待商榷。