tembotrione and mesotrione

Triketones, derived chemically from a natural phytotoxin (leptospermone), are a good example of allelochemicals as lead molecules for the development of new herbicides. Targeting a new and key enzyme involved in carotenoid biosynthesis, these latest-generation herbicides (sulcotrione, mesotrione and tembotrione) were designed to be eco-friendly and commercialized fifteen-twenty years ago. The mechanisms controlling their fate in different ecological niches as well as their toxicity and impact on different organisms or ecosystems are still under investigation. This review combines an overview of the results published in the literature on β-triketones and more specifically, on the commercially-available herbicides and includes new results obtained in our interdisciplinary study aiming to understand all the processes involved (i) in their transfer from the soil to the connected aquatic compartments, (ii) in their transformation by photochemical and biological mechanisms but also to evaluate (iii) the impacts of the parent molecules and their transformation products on various target and non-target organisms (aquatic microorganisms, plants, soil microbial communities). Analysis of all the data on the fate and impact of these molecules, used pure, as formulation or in cocktails, give an overall guide for the assessment of their environmental risks.

Topics: Cyclohexanones; Ecosystem; Ecotoxicology; Environment; Herbicides; Hydrogen-Ion Concentration; Ketones; Mesylates; Photochemistry; Plants; Risk Assessment; Soil; Soil Microbiology; Sulfones; Temperature; Water; Water Pollutants, Chemical

4-Hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor herbicides are widely used in modern agriculture. Plant root exudates (REs) play an important role in the adsorption, degradation, migration and transformation of pesticides in soil. In the present study, the structural affinity and interaction mechanism between four HPPD inhibitors (HPPDi) and soybean REs were investigated via multispectral technologies and two-dimensional correlation analysis (2D-COS). UV-vis absorption and fluorescence spectra showed that mesotrione, tembotrione, sulcotrione and topramezone effectively quench the intrinsic fluorescence of soybean REs through static quenching. The binding constant K

Topics: 4-Hydroxyphenylpyruvate Dioxygenase; Exudates and Transudates; Glycine max; Herbicides

The objective of this study was to evaluate the use of alternative herbicides to ACCase inhibitors to control

Topics: Atrazine; Desiccation; Digitaria; Enzyme Inhibitors; Glycine max; Herbicides

A population of Amaranthus tuberculatus (var. rudis) was confirmed resistant to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor herbicides (mesotrione, tembotrione, and topramezone) in a seed corn/soybean rotation in Nebraska. Further investigation confirmed a non-target-site resistance mechanism in this population. The main objective of this study was to explore the role of cytochrome P450 inhibitors in restoring the efficacy of HPPD-inhibitor herbicides on the HPPD-inhibitor resistant A. tuberculatus population from Nebraska, USA (HPPD-R).. Enhanced metabolism via cytochrome P450 enzymes is the mechanism of resistance in HPPD-R. Amitrole partially restored the activity of mesotrione, whereas malathion, amitrole, and piperonyl butoxide restored the activity of tembotrione and topramezone in HPPD-R. Although corn was injured through malathion followed by mesotrione application a week after treatment, the injury was transient, and the crop recovered.. The use of cytochrome P450 inhibitors with tembotrione may provide a new way of controlling HPPD-inhibitor resistant A. tuberculatus, but further research is needed to identify the cytochrome P450 candidate gene(s) conferring metabolism-based resistance. The results presented here aid to gain an insight into non-target-site resistance weed management strategies. © 2017 Society of Chemical Industry.

Topics: 4-Hydroxyphenylpyruvate Dioxygenase; Amaranthus; Cyclohexanones; Cytochrome P-450 Enzyme Inhibitors; Herbicide Resistance; Herbicides; Nebraska; Plant Proteins; Plant Weeds; Pyrazoles; Sulfones

A population of waterhemp in a seed maize production field in central Illinois, United States, was not adequately controlled after post-emergence applications of herbicides that inhibit 4-hydroxyphenylpyruvate dioxygenase (HPPD).. Progeny from the field population survived following treatment with mesotrione, tembotrione or topramezone applied to the foliage either alone or in combination with atrazine in greenhouse experiments. Dose-response experiments indicated that the level of resistance to the HPPD inhibitor mesotrione is at least tenfold relative to sensitive biotypes.. These studies confirm that waterhemp has evolved resistance to HPPD-inhibiting herbicides.

Topics: 4-Hydroxyphenylpyruvate Dioxygenase; Amaranthus; Atrazine; Biological Evolution; Cyclohexanones; Drug Resistance; Herbicides; Illinois; Pyrazoles; Sulfones