Uptake of Artificial Sweeteners in Wheat (Triticum Aestivum L.): Subcellular Distribution and Nontarget Identification of New Metabolites

Abstract

Artificial sweeteners, which serve as vital alternatives to sucrose, have been detected in agricultural soil and crops. There still knowledge gaps concerning the bioaccumulation of ASs in plants, which are crucial for assessing risks to ecosystems. The absorption, translocation and biotransformation of saccharin (SAC) and acesulfame (ACE) were investigated by a hydroponic experiment. Inhibition experiments indicated that the uptake of ASs by roots is an active, energy-requiring process, facilitated by both aquaporins and anion channels. Due to hydrophilic nature, SAC and ACE were prone to translocate to above-ground tissues via transpiration stream. The hydrophilicity also directs their primary storage in water-soluble cellular components, facilitating their acropetal translocation. The nontarget analysis utilizing high-resolution mass spectrometry identified 12 metabolites and potential degradation pathways were proposed. Apart from phase I metabolites, we also identified phase II metabolites that underwent methylation, glutathione, and glucuronide conjugation, marking their firstly detection in plants. The ecotoxicity of metabolites has been predicted and hydroxylated and methylated metabolites demonstrated higher toxicity. To our knowledge, this study pioneers the investigation of the mechanisms underlying the accumulation and biotransformation of ASs in plants, offering deeper insights into their behavior within plant systems.

Keywords: artificial sweeteners, subcellular distribution, high-resolution mass spectrometry, nontarget analysis, Biotransformation