GmCIM1-GmABCT1 complex facilitates nanoplastic uptake in soybean (Glycine max L.) roots via a membrane-associated mechanism

Nanoplastics (NPs) pose serious global environmental risks worldwide, with the food chain serving as the primary route for human exposure. However, the molecular mechanisms governing plant uptake of NPs remain unclear. Here, we investigated the roles of the major transmembrane protein GmCIM1 and the ABC transporter GmABCT1 in mediating NP transmembrane transport in soybean roots. Using CRISPR/cas9 and overexpression methods, two knockout and overexpression mutant strains for both genes were constructed. The NP content in roots of gmcim1 and gmabct1 knockout mutants was significantly reduced by 52.6% and 28.4%, respectively ( p < 0.05). Furthermore, yeast two-hybrid and pull-down assays confirmed a direct interaction between GmCIM1 and GmABCT1, indicating that they form a functional complex to cooperatively regulate the transmembrane transport of NPs. This partnership is functionally important, as evidenced by a significant reduction in root ATP levels (29.6% and 55.1% in gmcim1 and gmabct1 mutants, respectively). Together, these results demonstrate that GmCIM1 senses external NP stress via its transmembrane domain, interacts with GmABCT1 to recruit ATP, and is associated with ATP hydrolysis and required for efficient NP uptake. Consistent with these findings, experiments in a soil system showed that NP accumulation in roots of gmcim1 and gmabct1 mutants was significantly reduced by 45.7% and 69.0%, respectively. This study thus reveals a molecular complex critical for NP uptake and provides a strategy for breeding low-NP-accumulating soybean varieties for safer crop production.