Thiamethoxam Metabolism and Metabolic Effects in Cell Suspension Culture of Tea (Camellia sinensis L.)

Abstract

Thiamethoxam (TMX) has already been proven to have a physiological effect in plant tissue or cell expect for the insecticidal activity. In our previous study, TMX was verified to be metabolized by tea cells in either a suspension culture or tea plant into several metabolites. Here, tea cell suspension cultures were treated for 45 days to investigate the metabolite effects in both the tea cells and the culture supernatants by nontargeted metabolomics. Using multivariate analysis (PCA and OPLS-DA), all treatment and control groups could be clearly separated. Inside the cells, 113 metabolites were found to be upregulated while 122 were down-regulated, when compared with untreated cells. In the culture supernatant, there were 128 upregulated and 35 down-regulated metabolites, compared to untreated cultures. KEGG searches revealed that the alanine, aspartate, and glutamate metabolic pathways were strongly affected by TMX metabolism within the tea cell. Molecular docking models showed that (i) 4-aminobutyrate aminotransferase may be related to the formation of 2-chloro-thiazole-5-carboxylic acid and (ii) 3′(2′),5′-bisphosphate nucleotidase may be able to interact with TMX. This study can help us to understand the interaction mechanism of pesticides with plant cells.

Metabolic responses of tea (Camellia sinensis L.) to the insecticide thiamethoxam

“…The metabolic rate of TMX (30% SC, 1.5 X) in tea plants was consistent with that of our previous research, 13,28 the longer the treatment time, the lower the content of TMX in the tea plants with the higher degradation rate. However, the degradation rate of different concentrations of TMX in tea cell suspension cultures was lower than 50% at 75 days in our previous study, 13 while the degradation rate of TMX in tea plant reached about 93% at 7 days (Fig. 1B).…”

“…In addition to the direct interaction of TMX with certain enzymes, TMX may act as a signaling molecule regulating the gene expression activity, especially genes in certain metabolic pathways. 13 This work provided a theoretical basis for the interactions between plants and pesticides as well as the effect of pesticide application on tea quality and environmental risk assessment.…”

“…12 In our previous study, the metabolite response of tea cell suspension cultures treated with TMX was investigated by nontargeted metabolomics. 13 However, there are differences between dedifferentiated tea suspension cells and whole plants. The in vitro system of tea cell suspension cannot fully represent intact plants.…”

Deposition, Distribution, Metabolism, and Reduced Application Dose of Thiamethoxam in a Pepper-Planted Ecosystem

“…In this study, only three metabolites (TMX-dm, CLO, and C 5 H 8 O 2 N 3 SCl) were identified in the pepper plant and cultivated soil. However, Ge et al 29 reported that TMX could produce 235 metabolites inside tea plant cells and 163 metabolites in culture supernatant. WHO/FAO 30 reported that twenty-two TMX metabolites were detected from the excreta of rats.…”

Tratamento industrial de sementes com tiametoxam e inoculantes na sojicultura: desvendando o metabolismo dessa tecnologia

“…Sua molécula também mostra efeitos positivos na fisiologia e metabolismo vegetal para muitas culturas, como feijão (Cataneo et al 2010), trigo (Macedo and Castro 2011), arroz (Macedo et al 2013a;Lanka et al 2017), milho (Afifi et al 2015), soja (Cataneo et al 2010;Bortoletto et al 2017) e pastagens (Macedo et al 2013b) (Ge et al 2019). Devido aos efeitos proeminentes no vigor das plantas, ganhos no influxo de água, transporte de íons ou ativando o metabolismo primário e secundário, essa molécula foi classificada como bioativador (Macedo et al 2013b, a).…”