Target-Site Resistance to Fenoxaprop-P-ethyl in Keng Stiffgrass (Sclerochloa kengiana) from China

Abstract

Keng stiffgrass is a serious farmland grass weed distributed globally in winter wheat fields and rice–wheat double-cropping areas. The intensive use of acetyl-CoA carboxylase (ACCase)-inhibiting herbicides has led to the evolution of resistance in a growing number of grass weeds. In this study, whole-plant pot bioassay experiments were conducted to establish that a Keng stiffgrass population from eastern China, JYJD-2, has evolved high-level resistance to fenoxaprop-P-ethyl and moderate resistance to quizalofop-P-ethyl and pinoxaden. Using the derived cleaved amplified polymorphic sequence method, a tryptophan-to-cysteine mutation at codon position 1999 (W1999C) was detected in the ACCase gene of the resistant population JYJD-2. Of the 100 JYJD-2 plants tested, we found 47 heterozygous resistant and 53 homozygous sensitive individuals. In vitro ACCase assays revealed that the IC50value of the ACCase activity of the resistant population JYJD-2 was 6.48-fold higher than that of the susceptible population JYJD-1. To the best of our knowledge, this is the first report of the occurrence of W1999C mutation in the ACCase gene of fenoxaprop-P-ethyl–resistant Keng stiffgrass. This study confirmed the resistance of Keng stiffgrass to the ACCase inhibitor fenoxaprop-P-ethyl, cross-resistance to other ACCase inhibitors, and the resistance being conferred by specific ACCase point mutations at amino acid position 1999.

Design, Synthesis and Evaluation of Novel Trichloromethyl Dichlorophenyl Triazole Derivatives as Potential Safener

“…The herbicide FE was absorbed by the plant and converted into the corresponding acid, which reached the growth point of the plant meristem and the root growth point, affecting plant growth [36,37]. FE provoked a significant chlorosis and inhibition of growth for maize, but recovered when the safener fenchlorazole was included [38].…”

Fenoxaprop‐P‐ethyl resistance conferred by cytochrome P450s and target site mutation in Alopecurus japonicus

“…Fenoxaprop‐ P ‐ethyl resistance in A. japonicus is a major challenge for farmers planting wheat and oilseed rape. In China, six weed species have evolved resistance to ACCase‐inhibiting herbicides, namely A. japonicus , A. aequalis , Beckmannia syzigachne , Sclerochloa kengiana , Leptochloa chinensis and Echinochloa crus‐galli . Among these six weeds, fenoxaprop‐ P ‐ethyl resistance in A. japonicus was the most frequently reported .…”

Target-site and metabolic mechanisms of tolerance to penoxsulam in pond lovegrass (Eragrostis japonica)

“…The treated plants were returned to the incubators and cultured as described earlier. The fresh aboveground biomass was determined after 3 wk and expressed as a percentage of the untreated control (Feng et al 2016;Gao et al 2017). This experiment was conducted twice using a completely randomized design with four replicates.…”

“…Target enzymes with reduced sensitivity to herbicides are a common TSR mechanism in weeds, especially for herbicides with clear targets, such as ALS inhibitors, ACCase inhibitors, and the very-long-chain fatty-acid elongase synthesis inhibitors (Cai et al 2022;Fang et al 2019b;Gao et al 2017;Liu et al 2019;Xu et al 2013). In the current study, the sensitivity of ALS extracted from E. japonica was 12.27-fold lower than that of the susceptible weed E. crus-galli when treated with penoxsulam (Figure 1).…”