Auxin-Functionalized Nanocarriers Hijack Endogenous Transport for Systemic Crop Protection in Plants

Precise delivery of functional agents to specific plant organs remains a central challenge, as synthetic materials rarely access endogenous long-distance transport pathways. Here, we report an auxin-functionalized nanocarrier strategy that enables programmable systemic transport by interfacing engineered materials with plant signaling networks. Nanocarrier dimensions were tuned to ∼55 nm to limit endocytosis and favor extracellular localization, while auxin motifs were introduced on the particle surface. This design establishes a predominantly extracellular interface that hijacks polar auxin transport pathways. As a result, PIN-mediated fluxes are enhanced, accompanied by a 10.42-fold upregulation of PIN1, enabling directional leaf-to-root transport over centimeter scales and a 72.32-fold increase in root accumulation. This signal-coupled transport mechanism enables efficient root-targeted delivery of agrochemical cargos (abamectin) via foliar application, achieving up to 79.71% control of root-knot nematodes while reducing pesticide input by half. Furthermore, bypassing soil application provides a 3.20-fold higher ecological safety margin and yields a 16.47% increase in crop production. Beyond this application, the work establishes a generalizable design principle in which synthetic materials exploit endogenous signaling frameworks to navigate biological transport systems, opening new opportunities for systemic crop protection and bio-integrated material delivery.