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Research Project: New Weed Management Tools from Natural Product-Based Discoveries

Location: Natural Products Utilization Research

Title: Discovery for new herbicide sites of action by quantification of plant primary metabolite and enzyme pools

item DAYAN, F - Colorado State University
item Duke, Stephen

Submitted to: Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2019
Publication Date: 3/14/2020
Citation: Dayan, F.E., Duke, S.O. 2020. Discovery for new herbicide sites of action by quantification of plant primary metabolite and enzyme pools. Engineering. 6:509-514.

Interpretive Summary: Herbicides with new modes of action are badly needed for herbicide resistance management, but no such herbicide has been introduced for about 30 years. This paper describes two new herbicide discovery strategies that may result in herbicides with new modes of action. One is based on determination of plant enzymes with phytotoxic substrates and the other focuses on enzymes of low abundance in plant tissues.

Technical Abstract: No herbicide with a new molecular site of action (SOA) has been introduced since the 1980s. Since then, the widespread evolution of resistance of weeds to most commercial herbicides has greatly increased the need for herbicides with new SOAs. Two untried strategies for discovery on new herbicide SOAs are discussed. Some primary metabolism intermediates are phytotoxic (e.g., protoporphyrin IX, and sphingoid bases), and, because of this, the in vivo concentrations of these compounds are kept very low by plants. Determination of all primary metabolite phytotoxicities and pool sizes will identify targets of interest. Targeting SOAs that result in accumulation of identified compounds is the first novel approach to herbicide discovery. The second approach is to identify potential SOAs with very low in vivo enzyme levels. We know that higher numbers of enzyme molecules for a SOA requires more herbicide to kill a plant. Modern proteomic methods can identify low enzyme level SOAs for biorational herbicide discovery. These approaches might be useful in discovery of herbicides more closely related to natural compounds and that can be used in lower doses.