TWN Info Service on Biosafety
21 January 2022
Third World Network
www.twn.my
Dear Friends and Colleagues
GM Soy Exhibits Complex Metabolic Disturbances Under Stress Conditions
In the context of climate change, the combination of abiotic stressors is a reality in agroecosystems. A recent study investigated the unintended changes in the metabolism of stacked GM soybean plants under glyphosate spraying and water deficit conditions, by assessing their proteomic profiles compared to their non-transgenic conventional counterparts.
The study found clear evidence of increased metabolic costs in GM soybean plants in response to the accumulation of stress factors. When a combination of herbicide and drought stresses was applied to GM stacked varieties, analysis of the plant proteome revealed metabolic penalties due to stacking Cry and EPSPS transgenic traits. First, alterations in the ribosome pathway indicate that the GM plant itself carries a metabolic burden associated with the biosynthesis of proteins as effects of genetic transformation. GM plants also showed an imbalance in energy demand and production under controlled conditions, which was enhanced under drought conditions. Isolated herbicide stress revealed that GM plants have a period of sensitivity responses immediately after application. The combination of drought and herbicide stress resulted in numerous metabolic alterations. When the effects of genetic transformation are combined with accumulated abiotic stresses, more complex changes related to carbohydrate and energy metabolism and redox homeostasis disturbances were detected. Such findings suggest a staggering complexity of metabolic alterations as a response to the accumulation of stress factors and, consequently, the higher the costs to deal with this scenario.
These effects suggest a negative impact on plant composition, agronomic performance, and alterations in gene expression and regulation. The study therefore concludes that GM crop environments must be monitored from a biosafety perspective to verify potential risks in relationship with other biological organisms. Identifying the consequences of altered metabolism related to the interaction between plants and stress allows us to understand the possible effects on the ecology and evolution of plants in the medium and long term and the potential interactions with other organisms when GM organisms are released in the environment.
With best wishes,
Third World Network
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PROTEOMIC PROFILE OF GLYPHOSATE-RESISTANT SOYBEAN UNDER COMBINED HERBICIDE AND DROUGHT STRESS CONDITIONS
Benevenuto, R. F., Zanatta, C. B., Guerra, M. P., Nodari, R. O., & Agapito-Tenfen, S. Z.
Plants, 10(11), 2381
https://doi.org/10.3390/plants10112381
https://www.mdpi.com/2223-7747/10/11/2381
5 November 2021
Abstract
While some genetically modified (GM) plants have been targeted to confer tolerance to abiotic stressors, transgenes are impacted by abiotic stressors, causing adverse effects on plant physiology and yield. However, routine safety analyses do not assess the response of GM plants under different environmental stress conditions. In the context of climate change, the combination of abiotic stressors is a reality in agroecosystems. Therefore, the aim of this study was to analyze the metabolic cost by assessing the proteomic profiles of GM soybean varieties under glyphosate spraying and water deficit conditions compared to their non-transgenic conventional counterparts. We found evidence of cumulative adverse effects that resulted in the reduction of enzymes involved in carbohydrate metabolism, along with the expression of amino acids and nitrogen metabolic enzymes. Ribosomal metabolism was significantly enriched, particularly the protein families associated with ribosomal complexes L5 and L18. The interaction network map showed that the affected module representing the ribosome pathway interacts strongly with other important proteins, such as the chloro-plastic gamma ATP synthase subunit. Combined, these findings provide clear evidence for increasing the metabolic costs of GM soybean plants in response to the accumulation of stress factors. First, alterations in the ribosome pathway indicate that the GM plant itself carries a metabolic burden associated with the biosynthesis of proteins as effects of genetic transformation. GM plants also showed an imbalance in energy demand and production under controlled conditions, which was increased under drought conditions. Identifying the consequences of altered metabolism related to the interaction between plant transgene stress responses allows us to understand the possible effects on the ecology and evolution of plants in the medium and long term and the potential interactions with other organisms when these organisms are released in the environment.