posted on 2023-05-23, 15:03authored byGuoxin Liu, Xiaoxiao Feng, Yajing Guo, Xinyue Wang, Kai An, Jingao Dong, Yingchao Liu
Here, we investigated the uptake, transport, and subcellular
distribution
of the pesticides pymetrozine and spirotetramat, and spirotetramat
metabolites B-enol, B-glu, B-mono, and B-keto, under hydroponic conditions.
Spirotetramat and pymetrozine exhibited high bioconcentrations in
lettuce roots, with both having root concentration factor (RCF) values
>1 after exposure for 24 h. The translocation of pymetrozine from
roots to shoots was higher than that of spirotetramat. Pymetrozine
is absorbed in roots mainly via the symplastic pathway and is primarily
stored in the soluble fraction of lettuce root and shoot cells. The
cell wall and soluble fractions were the major enrichment sites of
spirotetramat and its metabolites in root cells. Spirotetramat and
B-enol were mainly enriched in the soluble fractions of lettuce shoot
cells, whereas B-keto and B-glu accumulated in cell walls and organelles,
respectively. Both symplastic and apoplastic pathways were involved
in spirotetramat absorption. Pymetrozine and spirotetramat uptake
by lettuce roots was passive, with no aquaporin-mediated dissimilation
or diffusion. The findings of this study enhance our understanding
of the transfer of pymetrozine, spirotetramat, and spirotetramat metabolites
from the environment to lettuce, and their subsequent bioaccumulation.
This study describes a novel approach for the efficient management
of lettuce pest control using spirotetramat and pymetrozine. At the
same time, it is of great significance to evaluate the food safety
and environmental risks of spirotetramat and its metabolites.