Molecular Basis for Resistance to Fluazifop-P-Butyl in Itchgrass (Rottboellia cochinchinensis) from Costa Rica (original) (raw)
Related papers
Weed Science
Itchgrass [Rottboellia cochinchinensis (Lour.) Clayton] is recognized as one of the most noxious and troublesome annual weeds in tropical and subtropical regions. Acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides have been frequently used for managing R. cochinchinensis POST in a variety of crops, resulting in evolved resistance to these herbicides. Recently, resistance to fluazifop-P-butyl has been demonstrated for this weed, as the result of a G-to-C single-nucleotide polymorphism (SNP) that leads to the Trp-2027-Cys substitution in the ACCase enzyme. This study was conducted to develop a high-resolution melting analysis (HRMA) for the detection of the mutation underlying the Trp-2027-Cys substitution. The HRMA assay allowed differentiating between fluazifop-P-butyl–resistant (C mutant) and susceptible (G wild type) R. cochinchinensis plants. HRMA accuracy was confirmed with DNA sequencing of the target-site mutation, and no false positives or negatives were observed. O...
Weed Science, 2018
Itchgrass [Rottboellia cochinchinensis (Lour.) Clayton] is recognized as one of the most noxious and troublesome annual weeds in tropical and subtropical regions. Acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides have been frequently used for managing R. cochinchinensis POST in a variety of crops, resulting in evolved resistance to these herbicides. Recently, resistance to fluazifop-P-butyl has been demonstrated for this weed, as the result of a G-to-C single-nucleotide polymorphism (SNP) that leads to the Trp-2027-Cys substitution in the ACCase enzyme. This study was conducted to develop a high-resolution melting analysis (HRMA) for the detection of the mutation underlying the Trp-2027-Cys substitution. The HRMA assay allowed differentiating between fluazifop-P-butyl-resistant (C mutant) and susceptible (G wild type) R. cochinchinensis plants. HRMA accuracy was confirmed with DNA sequencing of the target-site mutation, and no false positives or negatives were observed. Our results illustrated how HRMA is effective detecting the Trp-2027-Cys substitution in an R. cochinchinensis resistance, and how this technique can be of great value for developing high-throughput programs for monitoring evolution and dispersion of target site-based herbicide resistance at large scales.
Pesticide Biochemistry and Physiology, 1997
A population of Digitaria sanguinalis has evolved resistance to the herbicide fluazifop-P-butyl following selection with six applications of this herbicide over 4 years. The resistant population is also resistant to the chemically similar aryloxyphenoxypropanoate (APP) herbicides haloxyfop-methyl and quizalofop-Pethyl, shows a lower level of resistance to the cyclohexanedione (CHD) herbicide sethoxydim, but is not resistant to clethodim. Acetyl-coenzyme A carboxylase isolated from plants of both resistant and susceptible populations was equally sensitive to APP and CHD herbicides. Absorption of [ 14 C]fluazifop-butyl and translocation of 14 C from [ 14 C]fluazifop-butyl were similar in plants from both populations. Plants of both resistant and susceptible populations rapidly hydrolyzed [ 14 C]fluazifop-butyl to [ 14 C]fluazifop acid in leaves; however, [ 14 C]fluazifop acid was metabolised to other compounds at a more rapid rate in the resistant plants. Enhanced metabolism of the toxophore fluazifop acid is a likely mechanism of resistance in this population.
Pesticide Biochemistry and Physiology, 2001
A population of Digitaria sanguinalis selected by and resistant to the acetyl-coenzyme A carboxylaseinhibiting herbicide fluazifop-P-butyl is cross-resistant to the acetolactate synthase (ALS) inhibitor imazethapyr. The resistant population was six-fold resistant to imazethapyr despite never having been exposed to any ALS-inhibiting herbicide. ALS activity extracted from the resistant population was susceptible to imidazolinone herbicides. Malathion, a known cytochrome P450 monooxygenase inhibitor, synergized imazethapyr activity on the resistant population, suggesting that resistance is due to increased herbicide metabolism. In contrast, malathion antagonized fluazifop-P-butyl activity. Therefore, it is likely that the enzyme responsible for fluazifop acid detoxification in D. sanguinalis is different from the enzyme that detoxifies imazethapyr. ᭧ 2001 Elsevier Science 190
The Journal of Agricultural Science, 2014
The lack of control of barnyardgrass in flooded rice cultivated with imidazolinone-resistant rice cultivars is challenging the utilization of this system, which is continuously expanding for new rice areas worldwide. The objectives of the present study were to evaluate the frequency, distribution and mechanisms of imidazolinone resistance in barnyardgrass to establish the best practices to control and prevent this problem. The distribution of resistance was evaluated in 624 populations collected in Southern Brazil. The frequency of imidazolinoneherbicide resistance was 0·81, broadly distributed in all sampled regions. Resistance to quinclorac was also found in 0·19 of the populations, but all of the evaluated populations were susceptible to cyhalofop-butyl. Further studies were conducted in six populations. The enhanced metabolism was assessed with the metabolic inhibitors that reversed the resistance to quinclorac from 0·54 to 1·00 in two populations and the resistance to imazethapyr from 0·15 to 0·41 in three populations. The acetolactase synthase (ALS) enzyme activity also indicated the occurrence of altered target site resistance in two populations caused by the ALS gene mutations Trp574Leu and Ser653Asn, which is a novel finding in this species. The herbicide resistance in barnyardgrass in Southern Brazil presented a complex basis of resistance because it is associated with resistance to multiple herbicides due to multiple mechanisms and with multiple mutations of the ALS gene. This indicates that it is necessary to adopt specific measures to prevent and control the evolution of multiple herbicide resistance in this species.
Crop Science, 2019
Z oysiagrass (Zoysia spp.) is a warm-season turfgrass widely adopted in the transitional zone and southeastern regions of the United States due to good turf quality and low nutrient input requirements. Zoysiagrass exhibits more shade and winterkill tolerance than bermudagrass (Cynodon spp.), fewer disease and insect problems than St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze], and moderate salinity tolerance and wear tolerance compared with other warm-season grasses (Patton, 2010; Patton et al., 2017a). The most troublesome weeds in zoysiagrass turf are frequently other warm-season grasses with a similar growth habit and growing season. For example, bermudagrass is often one of the most problematic weeds to control, especially for golf courses during the process of transitioning from bermudagrass to zoysiagrass fairways (Johnson, 1992). Use of nonselective herbicides for long-term bermudagrass control is usually not practical and can be costly, since bermudagrass will eventually regrow from rhizomes and compete with the zoysiagrass (Johnson and Carrow, 1995). The aryloxyphenoxyproponiate (AOPP) herbicide fluazifop-P-butyl is labeled for bermudagrass suppression in zoysiagrass; however, previous studies reported significant injury to zoysiagrass despite nearly 100% control of bermudagrass (Johnson, 1987). Finding ways to increase the rate of AOPP
Journal of Agricultural and Food Chemistry, 2007
Fenoxaprop-p-ethyl (FE), 2-{4-[(6-chloro-2-benzoxazolyl)oxy]phenoxy} propanoate, ethyl ester (R), is an aryloxyphenoxypropionate herbicide for postemergence control of annual and perennial grasses in paddy fields; its site of action is acetyl-coenzyme A carboxylase (ACCase), an enzyme in fatty acids biosynthesis. The possible mechanism(s) of resistance to FE in a resistant biotype of Echinochloa phyllopogon was examined, namely, absorption, translocation, and metabolism of FE and ACCase susceptibility to fenoxaprop acid (FA). Studies of the in vitro inhibition of ACCase discounted any differential active site sensitivity as the basis of resistance to FE. There were differences in absorption rates between biotypes from 3 to 48 h after application (HAA). Biotypes did not differ in either the amounts or the rates of FE translocated; 98% of applied [ 14 C]FE remaining in the treated leaf. However, there was a good correlation between the rate of herbicide metabolism and the plant resistance. The R biotype produced 5-fold less FA and approximately 2-fold more nontoxic (polar) metabolites 48 HAA than the S biotype. Moreover, the higher rate of GSH conjugation in the resistant biotype as compared to the susceptible one indicates that GSH and cysteine conjugation is the major mechanism of resistance of the R biotype against FE toxicity.
Fluopyram activates systemic resistance in soybean
Frontiers in Plant Science
The soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is a significant yield-limiting factor in soybean production in the Midwestern US. Several management practices are implemented to mitigate yield losses caused by SCN, including using SDHI (succinate dehydrogenase inhibitors) fungicides delivered as seed treatments. A set of studies was conducted to evaluate the effect of two seed-applied succinate dehydrogenase inhibitors (SDHI) compounds, fluopyram and pydiflumetofen, on SCN population densities, plant injury, and plant growth. Cyst counts in untreated control and pydiflumetofen treated plants were 3.44 and 3.59 times higher than fluopyram, respectively, while egg counts were 8.25 and 7.06 times higher in control and pydiflumetofen. Next-generation sequencing was later employed to identify transcriptomic shifts in gene expression profiles in fluopyram and pydiflumetofen -treated seedlings. RNA expression patterns of seed treatments clustered by sampling time (5 DAP vs....
Pesticide Biochemistry and Physiology, 2002
A Rotala indica accession from Chonnam province, Korea was tested for resistance to sulfonylurea (SU) herbicide, imazosulfuron. The accession was confirmed to be resistant (R) and was cross-resistant to other SU herbicides, bensulfuron-methyl, cyclosulfamuron, and pyrazosulfuron-ethyl, but not to imidazolinone herbicides, imazapyr, and imazaquin. Multiple resistance was tested using eight herbicides with target sites other than acetolactate synthase (ALS). The R biotype was susceptible to other herbicides with different modes of action, such as fentrazamide and mefenacet. Herbicide mixtures, butachlor + pyrazolate and MCPB + molinate + simetryne can also control R biotype of R. indica. Although mixtures of SU herbicides with other modes of action can control the R biotype, use of these mixtures should be avoided. In vivo ALS activity of the R biotype was 35-, 26-, 278-, and 7-fold more resistant to bensulfuron-methyl, cyclosulfamuron, imazosulfuron, and pyrazosulfuron-ethyl, respectively, than the S biotype. The resistance mechanism of R. indica to imazosulfuron was mainly due to an alteration in the target enzyme, ALS. Since the level of resistance to other SU herbicides in the enzyme assay was much lower than that in the wholeplant assay, other mechanisms of resistance, such as herbicide metabolism, or reduced absorption and translocation may be involved. There was no indication of fitness difference between the R and S biotypes.