p-Cymene-Loaded Sucrose-Functionalized Carbon Dots as Phloem-Targeted Nanocarriers for Precision Control of Kiwifruit...

This study was designed to develop a phloem-targeted nanopesticide (PC@suc-β-cyclodextrins [β-CDs]) to combat the vascular invasion of Pseudomonas syringae pv. actinidiae (Psa), the causative pathogen of kiwifruit canker. Carbon quantum dots were functionalized with sucrose and β-CD and then loaded with p-cymene (PC). Remarkably, PC@suc-β-CDs exhibited a spherical shape (21.5 nm) and a drug-loading capacity of 15.2%. They also demonstrated improved antibacterial activity (EC₅₀ = 4.13 mg/L) against Psa, surpassing a conventional PC emulsion in water, with sucrose modification significantly enhancing their accumulation in the phloem (as visualized via confocal laser scanning microscopy). In pot trials, 300 mg/L PC@suc-β-CDs achieved a disease control efficiency of up to 84.75%, which is comparable to that of a commercial 2% kasugamycin aqueous solution, along with maintaining >98% cell viability in LO2 cells. Overall, the proposed sucrose‑guided nanodelivery system (PC@suc-β-CDs) represents a promising strategy for developing precision delivery systems to manage vascular-restricted plant diseases.