Enantioselective uptake, translocation, and biotransformation of pydiflumetofen in wheat ( Triticum aestivum L.): Insights from chiral profiling and molecular simulation

Pydiflumetofen (PYD), a highly effective and broad-spectrum fungicide, is commonly employed for the control of fungal diseases. In this study, the uptake, translocation, and biotransformation of PYD by wheat ( Triticum aestivum L.) were firstly investigated at a chiral level. The findings revealed that the residue concentration of R -PYD in wheat was higher than that of S -PYD, because of its higher uptake rate (k 1  = 0.0421 h −1 ) and lower elimination rate (k 2  = 0.0459 h −1 ). Additionally, R -PYD exhibited higher root bioconcentration factors and translocation factors compared with S- enantiomer, indicating R -PYD was more easily accumulating in roots and translocating to shoots. Furthermore, a total of 9 metabolites, including hydroxylated, demethylated, demethoxylated, dechlorinated, hydrolyzed, and glycosylated-conjugated products, were detected qualitatively in wheat roots or shoots. Symplastic pathway-mediated uptake, which predominantly relied on aquaporins and anion channels, was confirmed by root adsorption and inhibition experiments, without displaying any enantioselective effect. Molecular simulations demonstrated that R -PYD exhibited stronger binding affinity with Ta LTP 1.1 with a lower grid score (−6.79 kcal/mol), whereas weaker interaction with the metabolic enzyme (CYP71C6v1) compared to the S- enantiomer. These findings highlight the significance of plant biomacromolecules in the enantioselective bioaccumulation and biotransformation processes. Importantly, a combination of experimental and theoretical evidence provide a comprehensive understanding of the fate of chiral pesticides in plants from an enantioselective perspective.