Bidirectional uptake and redistribution, bio-stimuli responsive xyloglucan-based nanodelivery system for enhanced translocation of non-systemic pesticide in soybean plants

Abstract

Non-systemic pesticides, like fludioxonil, have the advantages of broad-spectrum and fast-acting, but the limited space of action restricts their effectiveness. This study proposed a nano-delivery strategy (Flu@EXG) by loading fludioxonil on aminated xyloglucan-based nanoparticles (EXG) to enhance the systematicity of fludioxonil in vivo and consequently achieve systemic defense against soybean diseases. The resulting Flu@EXG had an average diameter of 75.6 nm and exhibited responsive release properties to dual-stimuli of hemicellulases and pH value. The combined measurements of target dose and efficacy demonstrated that the Flu@EXG achieved bi-directional uptake and redistribution of fludioxonil, consequently inhibiting both Phytophthora sojae in roots and Botrytis cinerea on leaves meanwhile with a single application method (root irrigation or foliar spraying) in soybean. In contrast, fludioxonil commercial suspensions (Flu SC) hardly reached the roots to control root diseases when applied to foliage. Additionally, the direct inhibition of Flu@EXG against oomycetes was 2.0 times higher than Flu SC at high test concentrations as EXG could directly provide additional membrane damage. Finally, Flu@EXG provided comparable foliar performance to Flu SC and do not affect the growth of soybeans during the test cycle. Thus, the bio-stimuli responsive Flu@EXG nanodelivery system has promising for achieving the systemic prevention by overcoming the spatial and temporal limitations of non-systemic pesticide application, providing new perspectives and technologies for prompting sustainable development of agriculture.