Cypyrafluone, a 4-Hydroxyphenylpyruvate Dioxygenase Inhibitor to Control Weed in Wheat Fields

Abstract

As a bleaching herbicide, cypyrafluone was applied postemergence in wheat fields for annual weed control; especially, this herbicide possesses high efficacy against cool-season grass weed species such as Alopecurus aequalis and Alopecurus japonicus. In this study, the target of action of cypyrafluone on 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibition was confirmed. This herbicide caused severe foliar whitening symptoms at 5−7 days after treatment (DAT) and death of the whole plant within 10 DAT. Significant increases in phytoene content and significant decreases in kinds of carotenoid and chlorophyll pigments were observed. The content of chlorophyll pigments in cypyrafluone-treated Spirodela polyrhiza decreased upon the addition of homogentisic acid (HGA), which indicated that cypyrafluone prevents the HGA production, possibly by inhibiting the catalytic activity of 4-HPPD. Indeed, cypyrafluone strongly inhibited the catalytic activity of Arabidopsis thaliana HPPD produced by Escherichia coli, which was approximately 2 times less effective than mesotrione. In addition, overexpression of Oryza sativa HPPD in rice and A. thaliana both conferred a high tolerance level to cypyrafluone on them. Molecular docking found that cypyrafluone bonded well to the active site of the HPPD and formed a bidentate coordination interaction with the Fe 2+ atom, with distances of 2.6 and 2.7 Å between oxygen atoms and the Fe 2+ atom and a binding energy of −8.0 kcal mol −1 .

Dibenzylideneacetone Overcomes Botrytis cinerea Infection in Cherry Tomatoes by Inhibiting Chitinase Activity

“…These results further corroborated the actual inhibitory effect of DBA on Chitinase, consistent with the experimental assays (Figure B). The method of using computational biology results to complement experimental findings has gained widespread application. , …”

Design, Synthesis, and Herbicidal Evaluation of Pyrrolidinone-Containing 2-Phenylpyridine Derivatives as Novel Protoporphyrinogen Oxidase Inhibitors

“…Precisely, when AT reached the fourth leaf stage, compounds 4d , 4f , and 4l were applied at a dosage of 37.5 g ai/ha, and leaf tissue was collected 72 h after administration. The Chl content was determined according to the specific experimental methods stated in the kit instructions. − …”

Physiological Basis for the Mechanism of Selectivity of Tripyrasulfone between Rice (Oryza sativa) and Barnyard Grass (Echinochloa crus-galli)

“…After the treatments, the pots were placed in a greenhouse under the same conditions as those described above. At 21 days after treatment (DAT), the shoots from each pot were harvested and oven-dried at 80 °C for 72 h in an air-blowing box (model DHG-9140A, Changzhou Noki Instrument Co., Ltd., Changzhou, China), after which the dry weights were recorded and are expressed as percentages relative to those of the control group (percent of dry weight inhibition) . Three repetitions were set for each treatment, and the whole trial was conducted twice.…”

“…The preparation of purified recombinant rice and barnyard grass HPPD protein was conducted as previously reported. 13 The in vitro assay for HPPD activity was carried out according to Lian et al and Wang et al, 13,32 and the inhibitor HDT was added at final concentrations of 0.0001, 0.001, 0.01, 0.1, 1, 10, 100, and 1000 μM in the assay with the HPPD enzymes of A. thaliana, rice, and barnyard grass. Three repetitions were set for each treatment, and the whole trial was conducted twice.…”