Use of MTR Kinase Inhibitors as Selective Herbicides and Anti-Senescence Agents

The development of new herbicides continues to be an important agricultural concern in the U.S., where hundreds of millions of pounds of plant pesticides are used annually. The search for new agents that have low toxicities to non-target organisms (especially humans) requires the identification and exploitation of biochemical differences between plants and other higher eukaryotes. The enzyme methylthioribose (MTR) kinase serves as one such biochemical difference since its presence is restricted to plants, and some bacterial and protozoal species. MTR kinase inhibitors specifically interrupt methionine recycling from S-adenosylmethionine (AdoMet) used in the synthesis of polyamines. In doing so, they also limit the AdoMet available for the synthesis of the plant hormone ethylene, which controls the senescence of flowers and fruits. Here, we propose to evaluate MTR kinase inhibitors for their potential herbicidal activities as well as the ability to retard floral senescence. In this Phase I application, we will characterize the effects of MTR, analogs against recombinant Arabidopsis thaliana MTR kinase, and correlate this to effects on germination and seedling growth of A. thaliana and select agriculturally important crops and weeds. We will also examine the ability of these analogs to prolong the shelf-life of two economically important cut-flowers, roses and carnations.