Stacked genetically modified soybean harboring herbicide resistance and insecticide rCry1Ac shows strong defense and redox homeostasis disturbance after glyphosate application

Abstract

BackgroundWorld agricultural production of genetically modified (GM) products in particular, the combination of different traits/genes in the same plant has been intense over the last decade. The stacking of herbicide and insect-resistant transgenic genes can result in fitness costs that rely on the type and strength of the selection pressure exerted by the environment. Here we report the results of transcriptomic analysis comparing the effect of glyphosate on various biological processes, metabolic pathways, and main shikimic enzymes in stacked versus single soybean resistant varieties.ResultsGene expression data were grouped according to treatment, ie the herbicidal factor strongly influenced. Common physiological results between the single and established varieties were mainly in Redox metabolism, energy, and metabolism. Photosynthesis was only found negatively affected in the single variety. The defense components, although present in both varieties, show a more intense presence in staked pathways, that demonstrated pathways related to up-regulated secondary metabolites biosynthesis, a known response when plants are under various stress conditions. RT-PCR results confirmed that native EPSPS expression was up-regulated at the same level for single and stacked events. However, metabolic differences in expression were observed, suggesting a distinct cascade effect between simple and stacked, triggered by glyphosate application.ConclusionChanges in plant metabolism by glyphosate application have been observed in several pathways, particularly the shiquimate pathway, suggesting that event staking may promote a more intense defensive genetic response. Omics profiling techniques, such as transcriptome, can be considered tools to support risk assessment based on detecting unwanted effects, both on plant physiological changes and on the safety of foods and products from new genetic editing technologies.