Integrating hydroponic and soil-cultivated lettuce to understand the translocation, accumulation, subcellular distribution, and metabolism of chiral fungicide mandipropamid

Abstract

The accumulation and translocation of pesticides in crops can lead to several environmental hazards and pose potential threats to food safety and human health. This study demonstrated a strong absorption capacity of mandipropamid by soil-cultivated and hydroponic lettuce roots through an active symplastic pathway, as indicated by high root concentration and quasi-equilibrium factors. Mandipropamid moved minimally, with translocation factors < 1, and was primarily distributed in cell walls of lettuce tissues due to its hydrophobicity (logK_ow = 3.2) and low solubility (4.2 mg/L). Mandipropamid-contaminated cultivation media were remediated by planting lettuce, resulting in a reduction of half-lives by > 10 %, and enantioselectivity can be observed, with the R-enantiomer preferentially dissipating (enantiomeric factors < 0.5). Eleven potential metabolites were identified by high-resolution mass spectrometry during the cultivation process. This work provides integrated insights into the translocation, distribution, metabolism, and remediation of mandipropamid enantiomers in lettuce under soil-cultivated and hydroponic conditions.