Uptake, Translocation and Subcellular Distribution of Three Triazole Pesticides in Rice

Abstract Triazole pesticide is a widely-used pesticide for the control of pathogenic fungi in crops and its extensive use has caused food safety issues due to its uptake byedible crops. The residue of triazole pesticides has caused many toxicity risks and food safety problems. In this study, the uptake, translocation, and subcellular distribution of three triazole pesticides (triadimefon, tebuconazole, and epoxiconazole) in rice were investigated. The results showed that the three selected triazole pesticides could be taken up by rice roots, but their distribution in plant tissues was different. The accumulation of the three pesticides in rice root followed the order of epoxiconazole > tebuconazole > triadimefon, while a reversed order was observed in rice shoots. The movement of triazole pesticides within rice tissues involved both symplast and apoplast pathways, with triadimefon preferentially through the symplast pathway and epoxiconazole throughby the symplast pathway. The subcellular distribution reveals that all pesticides have a higher proportion in cell walls than in cell organelles and soluble components. Epoxiconazole has the highest accumulated capacity in the cell wall (45%-67%) and triadimefon was more concentrated in the soluble components (24%-29%). However, there exists no significant difference in the amount of three pesticides in cell organelles. The pesticide uptake, the movement of pesticides in symplast and apoplast, and the subcellular distribution of the three pesticides are related to the hydrophobicity of the three pesticides.