Efficacy of some pyrethroids against a strain of the rabbit ear mite ( Psoroptes cuniculi  ): an unusual cross-resistance pattern

1997 ◽  
Vol 83 (2) ◽  
pp. 203-205 ◽  
Author(s):  
László Pap ◽  
Péter Sárközy ◽  
Róbert Farkas ◽  
Edit Bleicher ◽  
András Szegö
Keyword(s):  
Cross Resistance ◽  
Resistance Pattern ◽  
Psoroptes Cuniculi ◽  
Rabbit Ear

First report of molecular basis of resistance to imazethapyr in common lambsquarters (Chenopodium album)

Weed Science ◽  
2019 ◽  
pp. 1-6
Author(s):  
Zhaofeng Huang ◽  
Xinxin Zhou ◽  
Chaoxian Zhang ◽  
Cuilan Jiang ◽  
Hongjuan Huang ◽  
...  
Keyword(s):  
Herbicide Resistance ◽  
Chenopodium Album ◽  
Acetolactate Synthase ◽  
Amino Acid Position ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
Susceptible Population ◽  
First Report ◽  
Common Lambsquarters

Abstract Common lambsquarters (Chenopodium album L.) is one of the most troublesome weeds in soybean [Glycine max (L.) Merr.] and corn (Zea mays L.) fields in northeast China. In 2017, a C. album population that survived imazethapyr at the recommended field rate was collected from a soybean field in Heilongjiang Province in China. Experiments were conducted to determine the basis of resistance to imazethapyr and investigate the herbicide-resistance pattern in C. album. Dose–response tests showed that the resistant population (R) displayed high resistance to imazethapyr (20-fold) compared with the susceptible population (S). An in vitro acetolactate synthase (ALS) activity assay indicated that the ALS of the R population was resistant to imazethapyr compared with the ALS of the S population. Sequence analysis of the ALS gene revealed that the GCA was replaced by ACA at amino acid position 122, which resulted in an alanine to threonine substitution (Ala-122-Thr) in the R population. The R population displayed cross-resistance to thifensulfuron-methyl and flumetsulam but susceptibility to bispyribac-sodium, flucarbazone, glyphosate, mesotrione, and fomesafen. These results confirmed that the basis of imazethapyr resistance in C. album was conferred by the Ala-122-Thr substitution in the ALS enzyme. This is the first report of the target-site basis of ALS-inhibiting herbicide resistance in C. album.

Detection and fitness of dicarboximide-resistant isolates of Alternaria alternata from Dendrobium officinale, a Chinese indigenous medicinal herb.

Plant Disease ◽  
2020 ◽  
Author(s):  
Weicheng Zhao ◽  
Chunxia Sun ◽  
Lingling Wei ◽  
Wenchan Chen ◽  
Bingran Wang ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Mycelial Growth ◽  
Medicinal Herb ◽  
Dendrobium Officinale ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
Amino Acid Sequence Alignment ◽  
Group I ◽  
Black Spots ◽  
Significant Difference

Black spots caused by Alternaria Alternata poses a sever threat to the industry of Dendrobium officinale, a Chinese indigenous medicinal herb. Dicarboximide fungicides (DCFs) are intensively used to control this disease for decades in China, and offering excellent efficacy. The resistance of phytopathogenic pathogens against DCFs are reportedly selected in fields; however, the DCF-resistance of A. alternata from D. officinale is not well understood. The low procymidone-resistant (ProLR) isolates of A. alternata were detected in the commercial orchards of D. officinale in China in 2018 and biochemically characterized in this study. The result showed that the low procymidone-resistant (ProLR) isolates were selected in the commercial orchards with the resistance frequency of 100 %, and no significant difference in mycelial growth, sporulation and virulence was observed among the ProLR and ProS isolates. A positive cross-resistance pattern was exhibited between procymidone and iprodione. Amino acid sequence alignment results of AaOS-1 from the tested isolates showed that all the ProLR genotypes could be categorized into two groups, including group I (mutations at AaOs-1) and group II (no mutation). On procymidone (5.0 μg/ml) treatment condition, the AaOs-1 expression levels increased in the ProS isolates ranged from 2.94~3.69 folds higher than those on procymidone-free condition, while the AaOs-1 expressions of the ProLR isolates were significantly lower than those in the ProS isolates on the same conditions. The data indicated that the mutations at AaOs-1 are involved in the DCF-resistance of A. alternata selected in the D. officinale orchards.

A Rare Ile-2041-Thr Mutation in the ACCase Gene Confers Resistance to ACCase-inhibiting Herbicides in Shortawn Foxtail (Alopecurus aequalis)

Weed Science ◽  
2017 ◽  
Vol 65 (2) ◽  
pp. 239-246 ◽  
Author(s):  
Wenlei Guo ◽  
Lele Zhang ◽  
Hengzhi Wang ◽  
Qi Li ◽  
Weitang Liu ◽  
...  
Keyword(s):  
Herbicide Resistance ◽  
Control Strategies ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
Susceptible Population ◽  
Dcaps Marker ◽  
Heterozygous Plant ◽  
Repeated Use ◽  
Moderate Resistance ◽  
Whole Plants

Understanding the mechanism of herbicide resistance is fundamental for designing sustainable weed control strategies and exploiting herbicides rationally. Shortawn foxtail is a problem grass weed infesting several important crops in China. The repeated use of acetyl-CoA carboxylase (ACCase)-inhibiting herbicides has resulted in herbicide resistance in this weed. The ACCase gene of resistant individuals of a shortawn foxtail population (JSLS-1) has an Ile-2041-Thr mutation. F2 generation seeds, originated from the same heterozygous plant, were harvested, and two homozygous mutant (JSLS-1RR) and wild (JSLS-1SS) populations for the Ile-2041-Thr mutation were obtained. In whole plants, the JSLS-1RR population conferred high resistance to fenoxaprop and clodinafop, moderate resistance to haloxyfop, low resistance to pinoxaden, and no obvious resistance to clethodim and sethoxydim, compared with JSLS-1SS and a proven susceptible population (HNXY-1). A derived cleaved amplified polymorphic sequence (dCAPS) marker was developed to rapidly detect the rare Ile-2041-Thr mutation in the shortawn foxtail population. This is the first report of the cross-resistance pattern of Ile-2041-Thr mutation, and the robust dCAPS marker could quickly detect this mutation in shortawn foxtail.

scholarly journals Disruption of a Cadherin Gene Associated with Resistance to Cry1Ac δ-Endotoxin of Bacillus thuringiensis in Helicoverpa armigera

2005 ◽  
Vol 71 (2) ◽  
pp. 948-954 ◽  
Author(s):  
Xinjun Xu ◽  
Liangying Yu ◽  
Yidong Wu
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Recessive Gene ◽  
Laboratory Strain ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
Bt Cotton ◽  
Helicoverpa Armígera

ABSTRACT A laboratory strain (GY) of Helicoverpa armigera (Hübner) was established from surviving larvae collected from transgenic cotton expressing a Bacillus thuringiensis var. kurstaki insecticidal protein (Bt cotton) in Gaoyang County, Hebei Province, People's Republic of China, in 2001. The GYBT strain was derived from the GY strain through 28 generations of selection with activated Cry1Ac delivered by diet surface contamination. When resistance to Cry1Ac in the GYBT strain increased to 564-fold after selection, we detected high levels of cross-resistance to Cry1Aa (103-fold) and Cry1Ab (>46-fold) in the GYBT strain with reference to those in the GY strain. The GYBT strain had a low level of cross-resistance to B. thuringiensis var. kurstaki formulation (Btk) (5-fold) and no cross-resistance to Cry2Aa (1.4-fold). Genetic analysis showed that Cry1Ac resistance in the GYBT strain was controlled by one autosomal and incompletely recessive gene. The cross-resistance pattern and inheritance mode suggest that the Cry1Ac resistance in the GYBT strain of H. armigera belongs to “mode 1,” the most common type of lepidopteran resistance to B. thuringiensis toxins. A cadherin gene was cloned and sequenced from both the GY and GYBT strains. Disruption of the cadherin gene by a premature stop codon was associated with a high level of Cry1Ac resistance in H. armigera. Tight linkage between Cry1Ac resistance and the cadherin locus was observed in a backcross analysis. Together with previous evidence found with Heliothis virescens and Pectinophora gossypiella, our results confirmed that the cadherin gene is a preferred target for developing DNA-based monitoring of B. thuringiensis resistance in field populations of lepidopteran pests.

scholarly journals First Line Anti-Tubercular Drug Resistance Pattern of Mycobacterium Tuberculosis Isolated From Specialized Hospitals of Dhaka City

2016 ◽  
Vol 8 (2) ◽  
pp. 41-46 ◽  
Author(s):  
Md Mohiuddin ◽  
J Ashraful Haq
Keyword(s):  
Drug Resistance ◽  
Extrapulmonary Tuberculosis ◽  
Surrogate Marker ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
First Line ◽  
Drug Resistance Pattern ◽  
Mdr Tb ◽  
Lowenstein Jensen ◽  
High Level

The present study was undertaken to determine the drug resistance pattern of M. tuberculosis isolated from 225 pulmonary and 45 extrapulmonary tuberculosis cases. The samples were cultured on Lowenstein Jensen (L-J) media for isolation of M. tuberculosis. Drug resistance to first line anti tubercular drugsnamely isoniazid (INH), rifampicin (RIF), Ethambutol (ETH) and streptomycin (SM) were determined by indirect proportion method. The overall drug resistance of M. tuberculosis was 53.6% to any of the first line anti tubercular drugs. Rate of multi drug resistant tuberculosis (MDR-TB) among the untreated cases was 4.2%, while it was 36.0% in previously treated cases. It was found that 83.3% rifampicin resistant M. tuberculosis was cross resistant to one or more of other first line anti-tubercular drugs, while cross resistance of INH, ETH and SM resistant isolates was much low. The present study revealed that high level of drug resistance exists to individual anti tubercular drugs and MDR-TB is an emerging problem, particularly in treated cases. Rifampicin resistance could be used as a surrogate marker for drug resistance to other first line anti tubercular drugs.Ibrahim Med. Coll. J. 2014; 8(2): 41-46

Effect of Ethalfluralin and Other Herbicides on Trifluralin-Resistant Green Foxtail (Setaria viridis)

1993 ◽  
Vol 7 (1) ◽  
pp. 6-14 ◽  
Author(s):  
Hugh J. Beckie ◽  
Ian N. Morrison
Keyword(s):  
Seed Production ◽  
Crop Production ◽  
Mechanisms Of Action ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
Yield Reduction ◽  
Setaria Viridis ◽  
Recommended Dosage ◽  
Green Foxtail ◽  
Chemical Groups

The response of trifluralin-susceptible (S) and -resistant (R) green foxtail biotypes to herbicides belonging to several chemical groups was compared to determine the cross-resistance pattern of the R-biotype. Dose-response experiments conducted in the growth chamber indicated that R-green foxtail was resistant to other dinitroanilines and a chemically unrelated mitotic disrupter herbicide, but not to nine other herbicides belonging to seven chemical families. The response of S- and R-green foxtail to increasing dosages of ethalfluralin, applied PPI in rapeseed, was investigated in a field experiment in 1989 and 1990. The R-biotype was 7 times more resistant to ethalfluralin than the S-biotype based on density determinations 4 wk after emergence. Seven times higher dosage was required to reduce R-seed production by 50% than to reduce S-seed production by the same amount. The initial reductions in density of R- and S-plants at the recommended dosage of ethalfluralin in rapeseed (1.4 kg ha−1) was 35% and 95%, respectively. The effective kill (seed yield reduction) of R- and S-biotypes was 55% and 99%, respectively. The results indicate that ethalfluralin will not effectively control R-green foxtail. However, several other herbicides with different mechanisms of action can be used to effectively control R-foxtail, thereby reducing any adverse effects of their interference on crop production.

scholarly journals Molecular Analysis of Cross-Resistance to Capreomycin, Kanamycin, Amikacin, and Viomycin in Mycobacterium tuberculosis

2005 ◽  
Vol 49 (8) ◽  
pp. 3192-3197 ◽  
Author(s):  
Courtney E. Maus ◽  
Bonnie B. Plikaytis ◽  
Thomas M. Shinnick
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Molecular Basis ◽  
Multidrug Resistant ◽  
Single Step ◽  
Clinical Isolates ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
Rrna Gene ◽  
Gene Encoding ◽  
Treatment Regimens

ABSTRACT Capreomycin, kanamycin, amikacin, and viomycin are drugs that are used to treat multidrug-resistant tuberculosis. Each inhibits translation, and cross-resistance to them is a concern during therapy. A recent study revealed that mutation of the tlyA gene, encoding a putative rRNA methyltransferase, confers capreomycin and viomycin resistance in Mycobacterium tuberculosis bacteria. Mutations in the 16S rRNA gene (rrs) have been associated with resistance to each of the drugs; however, reports of cross-resistance to the drugs have been variable. We investigated the role of rrs mutations in capreomycin resistance and examined the molecular basis of cross-resistance to the four drugs in M. tuberculosis laboratory-generated mutants and clinical isolates. Spontaneous mutants were generated to the drugs singularly and in combination by plating on medium containing one or two drugs. The frequencies of recovery of the mutants on single- and dual-drug plates were consistent with single-step mutations. The rrs genes of all mutants were sequenced, and the tlyA genes were sequenced for mutants selected on capreomycin, viomycin, or both; MICs of all four drugs were determined. Three rrs mutations (A1401G, C1402T, and G1484T) were found, and each was associated with a particular cross-resistance pattern. Similar mutations and cross-resistance patterns were found in drug-resistant clinical isolates. Overall, the data implicate rrs mutations as a molecular basis for resistance to each of the four drugs. Furthermore, the genotypic and phenotypic differences seen in the development of cross-resistance when M. tuberculosis bacteria were exposed to one or two drugs have implications for selection of treatment regimens.

Acetolactate synthase inhibitor-resistant stinkweed (Thlaspi arvense L.) in Alberta

2007 ◽  
Vol 87 (4) ◽  
pp. 965-972 ◽  
Author(s):  
H. J. Beckie ◽  
L. M. Hall ◽  
F. J. Tardif ◽  
G. Séguin-Swartz
Keyword(s):  
Herbicide Resistance ◽  
Dominant Gene ◽  
Acetolactate Synthase ◽  
Target Site ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
Site Mutation ◽  
Thlaspi Arvense ◽  
Synthase Inhibitor ◽  
Als Inhibitor

Two stinkweed populations from southern and central Alberta were not controlled by acetolactate synthase (ALS)-inhibiting herbicides in 2000. This study reports on their cross-resistance to ALS-inhibiting herbicides, molecular basis of resistance, and inheritance of resistance. Both putative herbicide-resistant biotypes responded similarly to increasing doses of the herbicides. The biotypes were highly resistant to ethametsulfuron and exhibited a low level of resistance to metsulfuron and imazethapyr. However, both biotypes were not resistant to florasulam, a triazolopyrimidine ALS inhibitor, or sulfometuron, a non-selective sulfonylurea ALS inhibitor. The cross-resistance pattern was consistent with the confirmed target-site mutation. Sequence analysis of the ALS gene detected a Pro197Leu mutation in both biotypes. Similar to many other ALS inhibitor-resistant weed biotypes, resistance was conferred by a single dominant gene. This study confirms the first global occurrence of herbicide resistance in this species. Key words: ALS-inhibitor resistance, ALS sequence, herbicide resistance, target-site mutation

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