Phloem Mobility of Xenobiotics VI. A Phloem-Mobile Pro-nematicide Based on Oxamyl Exhibiting Root-Specific Activation in Transgenic Tobacco

Article abstract of DOI:10.1002/ps.2780440103

Phloem mobility is a desirable attribute for pesticides in many applications, and the physicochemical properties necessary for phloem mobility are now well understood. However, attempts to derivatize pesticides to make them phloem mobile are often frustrated by a concomitant loss of activity. This study describes a phloem-mobile pro-nematicide, a hydroxymethyloxamyl glucuronide (JR522) coupled with an in-situ activation mechanism in transgenic tobacco expressing Escherichia coli β-glucuronidase in its root tips. When applied foliary to the transgenic tobacco, JR522 and its methyl ester (JM775) showed greater nematicidal activity than oxamyl against root-knot nematodes. This example of combining pro-pesticide chemistry with crop genetic engineering for site-specific activation provides a model system for demonstrating how to circumvent the often mutual exclusivity of phloem mobility and pesticidal activity. Additional advantages of this scheme include the potential mammalian safety of the pro-pesticide, as exhibited by JR522 in this study, and a high degree of site-specific release of xenobiotics in plants.