Development and Characterization of Diamondback Moth Resistance to Transgenic Broccoli Expressing High Levels of Cry1C

ABSTRACT A field-collected colony of the diamondback moth, Plutella xylostella, had 31-fold resistance to Cry1C protoxin ofBacillus thuringiensis. After 24 generations of selection with Cry1C protoxin and transgenic broccoli expressing a Cry1C protein, the resistance that developed was high enough that neonates of the resistant strain could complete their entire life cycle on transgenic broccoli expressing high levels of Cry1C. After 26 generations of selection, the resistance ratios of this strain to Cry1C protoxin were 12,400- and 63,100-fold, respectively, for the neonates and second instars by a leaf dip assay. The resistance remained stable until generation 38 (G38) under continuous selection but decreased to 235-fold at G38 when selection ceased at G28. The Cry1C resistance in this strain was seen to be inherited as an autosomal and incompletely recessive factor or factors when evaluated using a leaf dip assay and recessive when evaluated using Cry1C transgenic broccoli. Saturable binding of 125I-Cry1C was found with brush border membrane vesicles (BBMV) from both susceptible and Cry1C-resistant strains. Significant differences in Cry1C binding to BBMV from the two strains were detected. BBMV from the resistant strain had about sevenfold-lower affinity for Cry1C and threefold-higher binding site concentration than BBMV from the susceptible strain. The overall Cry1C binding affinity was just 2.5-fold higher for BBMV from the susceptible strain than it was for BBMV from the resistant strain. These results suggest that reduced binding is not the major mechanism of resistance to Cry1C.

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Polygenic and single gene responses to selection for resistance to diazinon in Lucilia cuprina.

Genetics ◽

10.1093/genetics/130.3.613 ◽

1992 ◽

Vol 130 (3) ◽

pp. 613-620 ◽

Cited By ~ 6

Author(s):

J A McKenzie ◽

A G Parker ◽

J L Yen

Keyword(s):

Resistant Strain ◽

Single Gene ◽

Natural Populations ◽

Susceptible Strain ◽

Selection Line ◽

Base Population ◽

Gene Response ◽

Biochemical Profiles ◽

Resistant Strains ◽

Selection For

Abstract Following mutagenesis with ethyl methanesulfonate, selection in a susceptible strain with a concentration of the insecticide diazinon (0.0004%, w/v) above that required to kill 100% of the susceptible strain, the LC100 of that strain, resulted in a single gene response. The resultant four mutant resistant strains have equivalent physiological, genetical and biochemical profiles to a diazinon-resistant strain derived from a natural population and homozygous for the Rop-1 allele. Modification of the microsomal esterase E3 is responsible for resistance in each case. The Rop-1 locus maps approximately 4.4 map units proximal to bu on chromosome IV. Selection within the susceptible distribution, at a concentration of diazinon [0.0001% (w/v)] less than the LC100, resulted in a similar phenotypic response irrespective of whether the base population had been mutagenized. The responses were polygenically based, unique to each selection line and independent of Rop-1. The relevance of the results to selection for insecticide resistance in laboratory and natural populations is discussed.

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In vitro anti-mycobacterial activity of (E)-N´-(monosubstituted-benzylidene) isonicotinohydrazide derivatives against isoniazid-resistant strains

Infectious Disease Reports ◽

10.4081/idr.2012.e13 ◽

2012 ◽

Vol 4 (1) ◽

pp. 13 ◽

Cited By ~ 8

Author(s):

Tatiane S. Coelho ◽

Jessica B. Cantos ◽

Marcelle L.F. Bispo ◽

Raoni S.B. Gonçalves ◽

Camilo H.S. Lima ◽

...

Keyword(s):

Antibacterial Activity ◽

Resistant Strain ◽

Mechanisms Of Action ◽

Susceptible Strain ◽

Clinical Isolates ◽

Coding Region ◽

Resistant Strains

A series of twenty-three N-acylhydrazones derived from isoniazid (INH 1-23) have been evaluated for their in vitro antibacterial activity against INH- susceptible strain of M. tuberculosis (RG500) and three INH-resistant clinical isolates (RG102, RG103 and RG113). In general, derivatives 4, 14, 15 and 16 (MIC=1.92, 1.96, 1.96 and 1.86 mM, respectively) showed relevant activities against RG500 strain, while the derivative 13 (MIC=0.98 mM) was more active than INH (MIC=1.14 mM). However, these derivatives were inactive against RGH102, which displays a mutation in the coding region of inhA. These results suggest that the activities of these compounds depend on the inhibition of this enzyme. However, the possibility of other mechanisms of action cannot be excluded, since compounds 2, 4, 6, 7, 12-17, 19, 21 and 23 showed good activities against katG-resistant strain RGH103, being more than 10-fold more active than INH.

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Genetic Characterization of Fluoroquinolone-Resistant Streptococcus pneumoniae Strains Isolated during Ciprofloxacin Therapy from a Patient with Bronchiectasis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.4.1419-1422.2003 ◽

2003 ◽

Vol 47 (4) ◽

pp. 1419-1422 ◽

Cited By ~ 16

Author(s):

Adela G. de la Campa ◽

María-José Ferrandiz ◽

Fe Tubau ◽

Román Pallarés ◽

Federico Manresa ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Genetic Characterization ◽

Susceptible Strain ◽

Low Level ◽

Resistant Strains ◽

Resistant Mutants ◽

High Level ◽

Level Resistance

ABSTRACT Five Spain9V-3 Streptococcus pneumoniae strains were isolated from a patient with bronchiectasis who had received long-term ciprofloxacin therapy. One ciprofloxacin-susceptible strain was isolated before treatment, and four ciprofloxacin-resistant strains were isolated during treatment. The resistant strains were derived from the susceptible strain either by a parC mutation (low-level resistance) or by parC and gyrA mutations (high-level resistance). This study shows that ciprofloxacin therapy in a patient colonized by susceptible S. pneumoniae may select fluoroquinolone-resistant mutants.

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Comparisons Between the Response of German Cockroach Field-Collected Strains (Dictyoptera: Blattellidae) to Vapors and Contact with a Cyfluthrin Formulation

Journal of Entomological Science ◽

10.18474/0749-8004-28.2.168 ◽

1993 ◽

Vol 28 (2) ◽

pp. 168-174 ◽

Cited By ~ 2

Author(s):

Mary H. Ross

Keyword(s):

Resistant Strain ◽

German Cockroach ◽

Susceptible Strain ◽

Late Instar ◽

Resistant Strains ◽

Biochemical Resistance

Research on differences in insecticide-induced behavior of German cockroach field-collected strains was continued. Late instar nymphs (5th–6th stadia) were drawn from the Fairbanks, an insecticide susceptible strain, and two pyrethroid resistant strains, the Jacksonville and Forest Green. Dispersal induced by vapors of a cyfluthrin flowable concentrate (FC) and the FC formulation base (blank) was compared with response to the FC and the FC blank when dry. Jacksonville nymphs avoided the dried FC, but not as strongly as Fairbanks strain nymphs. The Al played a major role in eliciting avoidance by Fairbanks strain nymphs but, in the Jacksonville strain, avoidance was due more to an ingredient(s) of the formulation base. Forest Green nymphs did not avoid the dried FC or the FC blank. Vapors of the FC and the FC blank caused rapid dispersal of all strains, but dispersal of resistant strain nymphs was slower than that of susceptible strain nymphs. Although Jacksonville nymphs responded more strongly to the dried formulation than Forest Green nymphs, the response to vapors was weaker than that of Forest Green nymphs. It is suggested that localized populations of the German cockroach have developed many different combinations of behavioral modifications and physiological/biochemical resistance.

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CROSSOVER VALUES BETWEEN DIELDRIN-RESISTANCE AND DDT-RESISTANCE AND LINKAGE-GROUP-2 GENES IN AEDES AEGYPTI

Canadian Journal of Genetics and Cytology ◽

10.1139/g70-058 ◽

1970 ◽

Vol 12 (3) ◽

pp. 407-414 ◽

Cited By ~ 12

Author(s):

W. L. Lockhart ◽

W. Klassen ◽

A. W. A. Brown

Keyword(s):

Linkage Group ◽

Aedes Aegypti ◽

Resistant Strain ◽

Susceptible Strain ◽

Total Distance ◽

Resistant Strains ◽

Ddt Resistance ◽

Group 2

Crosses and backcrosses between five dieldrin-resistant strains and the MYS susceptible strain in Aedes aegypti indicate the order of the genes to be Dl—si — s, the distance si — s being 6-7 units and the total distance Dl — s being 25-31 units.Crosses between the Trinidad DDT-resistant strain and the MYS marker strain indicate the order to be si — s — DDT, the distance si — s being 4 units and the total distance s — DDT being 10 units. Crosses between this strain and the AO and Multiple marker strains indicate the order to be y — s — DDT.These results indicate that the order of the genes in linkage-group 2 of Aedes aegypti is probably Dl — si — y —s — DDT. The total crossover distance of some 45 units thus implied between Dl and DDT is, however, at variance with previous work which found the direct crossover between these two genes to be only 4-7%.

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THE PRODUCTION OF A DDT-RESISTANT STRAIN OF AEDES AEGYPTI MARKED ON ALL THREE LINKAGE GROUPS

Canadian Journal of Genetics and Cytology ◽

10.1139/g74-095 ◽

1974 ◽

Vol 16 (4) ◽

pp. 883-888 ◽

Cited By ~ 4

Author(s):

J. P. Margham ◽

R. J. Wood

Keyword(s):

Aedes Aegypti ◽

Resistance Genes ◽

Resistant Strain ◽

Genetic Background ◽

Adult Stage ◽

Susceptible Strain ◽

Linkage Studies ◽

Linkage Groups ◽

Resistant Strains ◽

Major Resistance Genes

DDT-resistant strains marked on all three linkage groups have been produced by selection at the adult stage after outcrossing a resistant strain (BANGKOK-HR) to a marked susceptible strain (64). The most resistant and viable line (BANGKOK-MR) was kept for linkage studies. The production of a marked resistant strain was not entirely straightforward. In the absence of a suitable genetic background, major resistance genes conferred little or no DDT tolerance and could not be selected. Selection at the adult stage produced resistance in larvae as well as in adults. Resistance was achieved more rapidly in larvae than in adults

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Some properties of l-chloro-2,4-dinitrochlorobenzene linked glutathione S-transferase in dichlorvos resistant and susceptible strains of cotton aphid (Homoptera: Aphididae)

The Journal of Agricultural Science ◽

10.1017/s0021859600078692 ◽

1996 ◽

Vol 127 (4) ◽

pp. 469-473 ◽

Cited By ~ 6

Author(s):

E. O. Owusu ◽

M. Horiike

Keyword(s):

Enzyme Activity ◽

Resistant Strain ◽

Aphis Gossypii ◽

Susceptible Strain ◽

Glutathione S Transferase ◽

Cotton Aphid ◽

High Positive Correlation ◽

Application Frequency ◽

Resistant Strains ◽

Two Parameters

SUMMARYEffects of temperature, hydrogen ion and substrate concentrations on conjugation of l-chloro-2,4-dinitrochlorobenzene by glutathione S-transferase from susceptible and dichlorvos-resistant strains of cotton aphid (Aphis gossypii Glover (Homoptera: Aphididae)) were evaluated. Enzymes from both strains had common optimum temperature and substrate concentration values of 30 °C and 10 mM respectively. Also, while enzyme activity of the susceptible strain peaked at pH 7·2, that of the resistant strain showed complete linear dependency up to pH 8·0. Of four subcellular fractions, the 100 000 g supernatant (soluble fraction) gave the highest enzyme activity in both phosphate and Tris/HCl buffers. There was no linear relationship between insecticide application frequency and production of enzyme activity in the susceptible strain but there was a very high positive correlation between these two parameters in the resistant strain.

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Biochemical characterization of chlorphoxim resistance in adults and larvae of the Simulium damnosum complex (Diptera: Simuliidae)

Bulletin of Entomological Research ◽

10.1017/s0007485300031965 ◽

1991 ◽

Vol 81 (4) ◽

pp. 401-406 ◽

Cited By ~ 5

Author(s):

J. Hemingway ◽

A. Callaghan ◽

D.C. Kurtak

Keyword(s):

Resistant Strain ◽

Biochemical Characterization ◽

Sodium Dithionite ◽

Control Programme ◽

Susceptible Strain ◽

Difference Spectra ◽

General Esterase ◽

Naphthyl Acetate ◽

Onchocerciasis Control

AbstractChlorphoxim resistance is found in forest strains of Simulium sanctipauli Vajime & Dunbar, in some areas of the Onchocerciasis Control Programme in West Africa. There is an increase in esterase activity in both adults and larvae in the resistant compared to the susceptible strain with the general esterase substrate 1-naphthyl acetate. This appears to be associated with the temephos and chlorphoxim resistance which are found in the same resistant strain. It is possible that one or more esterases are qualitatively and/or quantitatively changed in the resistant strain compared to the susceptible. Preliminary studies indicated that esteratic hydrolysis and oxidative cleavage were both involved in chlorphoxim metabolism in S. damnosum Theobald sensu latu. There was evidence of an increase in detoxication by both these routes in the resistant compared to the susceptible strain of the cytospecies S. sanctipauli. The increase in oxidative detoxication seen in the resistant strain was associated with a slight, but non-significant increase in cytochrome P450 as measured by the sodium dithionite reduced carbon monoxide difference spectra.

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Cross-Resistance and Stability of Resistance to Bacillus thuringiensis Toxin Cry1C in Diamondback Moth

Applied and Environmental Microbiology ◽

10.1128/aem.67.7.3216-3219.2001 ◽

2001 ◽

Vol 67 (7) ◽

pp. 3216-3219 ◽

Cited By ~ 21

Author(s):

Yong-Biao Liu ◽

Bruce E. Tabashnik ◽

Susan K. Meyer ◽

Neil Crickmore

Keyword(s):

Bacillus Thuringiensis ◽

Plutella Xylostella ◽

Resistant Strain ◽

Diamondback Moth ◽

Field Population ◽

Cross Resistance ◽

Bacillus Thuringiensis Toxin ◽

Stability Of Resistance ◽

Resistant Strains ◽

Reported Data

ABSTRACT We tested toxins of Bacillus thuringiensis against larvae from susceptible, Cry1C-resistant, and Cry1A-resistant strains of diamondback moth (Plutella xylostella). The Cry1C-resistant strain, which was derived from a field population that had evolved resistance to B. thuringiensis subsp.kurstaki and B. thuringiensis subsp.aizawai, was selected repeatedly with Cry1C in the laboratory. The Cry1C-resistant strain had strong cross-resistance to Cry1Ab, Cry1Ac, and Cry1F, low to moderate cross-resistance to Cry1Aa and Cry9Ca, and no cross-resistance to Cry1Bb, Cry1Ja, and Cry2A. Resistance to Cry1C declined when selection was relaxed. Together with previously reported data, the new data on the cross-resistance of a Cry1C-resistant strain reported here suggest that resistance to Cry1A and Cry1C toxins confers little or no cross-resistance to Cry1Bb, Cry2Aa, or Cry9Ca. Therefore, these toxins might be useful in rotations or combinations with Cry1A and Cry1C toxins. Cry9Ca was much more potent than Cry1Bb or Cry2Aa and thus might be especially useful against diamondback moth.

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Genetic and Biochemical Approach for Characterization of Resistance to Bacillus thuringiensis Toxin Cry1Ac in a Field Population of the Diamondback Moth, Plutella xylostella

Applied and Environmental Microbiology ◽

10.1128/aem.66.4.1509-1516.2000 ◽

2000 ◽

Vol 66 (4) ◽

pp. 1509-1516 ◽

Cited By ~ 114

Author(s):

Ali H. Sayyed ◽

Robert Haward ◽

Salvador Herrero ◽

Juan Ferré ◽

Denis J. Wright

Keyword(s):

Bacillus Thuringiensis ◽

Plutella Xylostella ◽

Diamondback Moth ◽

Resistance Mechanism ◽

Membrane Vesicles ◽

Cross Resistance ◽

Binding Studies ◽

Susceptible Population ◽

Biochemical Approach

ABSTRACT Four subpopulations of a Plutella xylostella (L.) strain from Malaysia (F4 to F8) were selected with Bacillus thuringiensis subsp.kurstaki HD-1, Bacillus thuringiensis subsp. aizawai, Cry1Ab, and Cry1Ac, respectively, while a fifth subpopulation was left as unselected (UNSEL-MEL). Bioassays at F9 found that selection with Cry1Ac, Cry1Ab, B. thuringiensissubsp. kurstaki, and B. thuringiensis subsp. aizawai gave resistance ratios of >95, 10, 7, and 3, respectively, compared with UNSEL-MEL (>10,500, 500, >100, and 26, respectively, compared with a susceptible population, ROTH). Resistance to Cry1Ac, Cry1Ab, B. thuringiensis subsp. kurstaki, andB. thuringiensis subsp. aizawai in UNSEL-MEL declined significantly by F9. The Cry1Ac-selected population showed very little cross-resistance to Cry1Ab, B. thuringiensis subsp. kurstaki, andB. thuringiensis subsp. aizawai(5-, 1-, and 4-fold compared with UNSEL-MEL), whereas the Cry1Ab-,B. thuringiensis subsp. kurstaki-, and B. thuringiensis subsp.aizawai-selected populations showed high cross-resistance to Cry1Ac (60-, 100-, and 70-fold). The Cry1Ac-selected population was reselected (F9 to F13) to give a resistance ratio of >2,400 compared with UNSEL-MEL. Binding studies with125I-labeled Cry1Ab and Cry1Ac revealed complete lack of binding to brush border membrane vesicles prepared from Cry1Ac-selected larvae (F15). Binding was also reduced, although less drastically, in the revertant population, which indicates that a modification in the common binding site of these two toxins was involved in the resistance mechanism in the original population. Reciprocal genetic crosses between Cry1Ac-reselected and ROTH insects indicated that resistance was autosomal and showed incomplete dominance. At the highest dose of Cry1Ac tested, resistance was recessive while at the lowest dose it was almost completely dominant. The F2 progeny from a backcross of F1 progeny with ROTH was tested with a concentration of Cry1Ac which would kill 100% of ROTH moths. Eight of the 12 families tested had 60 to 90% mortality, which indicated that more than one allele on separate loci was responsible for resistance to Cry1Ac.

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