Action mechanism of isoxazoline-type herbicides

Abstract

Two isoxazoline-type herbicides, pyroxasulfone and fenoxasulfone have been developed by Kumiai Chemical Industry Co., Ltd., K-I Chemical Research Institute Co., Ltd., and Ihara Chemical Industry Co., Ltd. The former is a novel herbicide for use in wheat, corn, soybean and other crops and the latter is a novel herbicide for paddy fields. This study revealed that these isoxazoline-type herbicides potently inhibit very-long-chain fatty acid elongases (VLCFAEs), which catalyze the biosynthesis of very-long-chain fatty acids (VLCFAs) in plants and should be categorized within the K3 group of the Herbicide Resistance Action Committee (HRAC). Furthermore, the reversible inhibition manner of plant VLCFAEs by pyroxasulfone and fenoxasulfone proposed a new inhibition mechanism of VLCFAEs which is completely different from the commonly accepted hypothesis that VLCFAE-inhibiting herbicides irreversibly react with VLCFAEs as chloroacetoamide-type herbicides do. © Pesticide Science Society of Japan.