Potential Toxic Mechanisms of Neonicotinoid Insecticides in Rice: Inhibiting Auxin-Mediated Signal Transduction

Abstract

Inappropriate application of pesticides not only causes sub-lethal effects on ecosystem service providers but also reduces crop yield and quality. As a xenobiotic signal molecule, pesticides may interact with signal transduction receptors in crops, resulting in oxidative damage and even metabolic perturbations. We discovered that three neonicotinoid insecticides (NIs), namely, imidacloprid, thiamethoxam, and clothianidin, at 0.06–0.12 kg ai/ha significantly inhibited the auxin signal pathway in rice leaves, thereby reducing the intracellular auxin (IAA) content. Molecular simulation further confirmed that NIs occupied the binding site where auxin transporter-like proteins 1 (LAX11) and 2 (LAX12), in which Thr253 and Asn66 of LAX11, as well as Thr244 and Asn57 of LAX12, were bound to the nitroguanidine of NIs via H-bonds. Meanwhile, Asn66 of LAX11 and Asn57 of LAX12 interacted with nitroguanidine via aromatic H-bonds. Moreover, phenylpropanoid biosynthesis was significantly disturbed because of the inhibited auxin signal pathway. Notably, peroxidase-coding genes were downregulated with a maximum value greater than 10-fold, resulting in decreased antioxidant metabolites flavone (37.82%) and lignin content (20.15%). Ultimately, rice biomass was reduced by up to 25.41% due to the decline in IAA content and antioxidant capacity. This study deeply explored the molecular mechanism of metabolic perturbations in crops stressed by pesticides, thus providing a scientific basis for pesticide environmental risk assessment and agricultural product safety.

Stable Aggregate Formation and Microbial Diversity Resilience in Soil Formation of Bauxite Residue: Roles of Extracellular Polymeric Substances Secreted by Penicillium oxalicum

“…Previously found that proteins in the EPS of Bacillus subtilis were primarily adsorbed on montmorillonite surfaces via hydrogen bonds, while nucleic acids were adsorbed on goethite surfaces through ligand exchange in an acidic medium . Environmental pressures had a significant impact on microbial extracellular metabolic behavior, and the alkalinity of bauxite residue amplified this effect . Thereby, polysaccharides with abundant carboxyl functional groups were preferred by cancrinite and sodalite.…”

“…The protein was analyzed by using an HPLC system (Thermo Fisher Scientific ICS5000) and a CarbonPac PA20 C 18 column (3 mm × 150 mm, 10 μm). The mobile phase was NaOH/NaAc (95:5, v/v) injected at a flow rate of 0.5 mL/min, 30 °C, and detected at 230 nm …”

Will EGFRvIII and neuronal-derived EGFR be targets for imipramine?

“…Finally, the complex with the lowest score was selected for further study. The molecular dynamics simulation protocol can be found in previous article ( Wu et al, 2023 ).…”

Relationship Between Chemical Treatment of Soybean (Glycine max (L.) Merr.) Seeds and Synthesis of Antioxidant Enzymes

“…From this same perspective, Wu et al (2023) argue that neonicotinoid insecticides favor the occurrence of changes in the biosynthesis of phenylpropanoids, modifications in genes that encode peroxidases, culminating in oxidative stress and a decrease in antioxidant metabolites. Concerning the comparison between storage periods, for the "Peroxidase protein" and "Peroxidase activity" variables, there were significant differences between them (p-value < 0.05).…”