Levels, inheritance and stability of resistance to Bacillus thuringiensis formulation in a field population of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) from Thailand

Imai, Katsuki; Mori, Yuhzoh

doi:10.1303/aez.34.23

Cited by 14 publications

(11 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The MEL population was divided into five subpopulations at F 4 . One subpopulation was left unselected (UNSEL-MEL), while the other four were selected (22) with B. thuringiensis subsp. kurstaki (B. thuringiensis subsp.…”

mentioning

confidence: 99%

See 1 more Smart Citation

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

Sayyed

Haward

Herrero

et al. 2000

Appl Environ Microbiol

143

147

View full text Add to dashboard Cite

Four subpopulations of a Plutella xylostella (L.) strain from Malaysia (F 4 to F 8 ) 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 F 9 found that selection with Cry1Ac, Cry1Ab, B. thuringiensis subsp. 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, and B. thuringiensis subsp. aizawai in UNSEL-MEL declined significantly by F 9 . The Cry1Ac-selected population showed very little cross-resistance to Cry1Ab, B. thuringiensis subsp. kurstaki, and B. 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 (F 9 to F 13 ) to give a resistance ratio of >2,400 compared with UNSEL-MEL. Binding studies with 125 I-labeled Cry1Ab and Cry1Ac revealed complete lack of binding to brush border membrane vesicles prepared from Cry1Ac-selected larvae (F 15 ). 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 F 2 progeny from a backcross of F 1 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.

show abstract

mentioning

confidence: 99%

“…aizawai. Test solutions were prepared in distilled water with Triton X-100 (50 g ml Ϫ1 ) as an additional surfactant (22). Each leaf disk (4.8-cm diameter) was immersed in a test solution for 10 s and allowed to dry at ambient temperature for 1 h (23).…”

mentioning

confidence: 99%

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

Sayyed

Haward

Herrero

et al. 2000

Appl Environ Microbiol

143

147

View full text Add to dashboard Cite

show abstract

“…High levels of resistance to B. thuringiensis toxins have evolved several times in field populations of P. xylostella moths (21,26,55). Until the present study, fully characterized resistance to B. thuringiensis or Bacillus sphaericus has been described only for populations that have undergone reselection in the laboratory (10,14,44,45,50).…”

Section: Discussionmentioning

confidence: 81%

“…In similar microcosm experiments over 12 generations with another Malaysian population, SERD4, that had been reselected in the laboratory, resistance declined rapidly at a rate of Ϫ0.40 (8). Previous stability studies have cultured B. thuringiensisresistant lepidoptera on either Brassica napus (26,55), Brassica oleracea (51), radish, Raphanus sativus (21), or an artificial diet (27), whereas all our experiments with P. xylostella populations a The expected number of larvae dead at given dose is the starting number times 0.5 (the proportion of F 1 larvae that die plus the proportion of field larvae that die).…”

mentioning

confidence: 90%

“…kurstaki) over 11 generations in the absence of selection. Typically, high levels of resistance to B. thuringiensis have been reported to decline very quickly (8,21,26,45,52,55), irrespective of whether populations have been selected in the laboratory or the field. A slow loss of resistance (R Ͻ Ϫ0.05) is normally associated only with low-to-moderate B. thuringiensis resistance (Ͻ100-fold), as has been found for Plodia interpunctella (36).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Genetic and Biochemical Characterization of Field-Evolved Resistance to Bacillus thuringiensis Toxin Cry1Ac in the Diamondback Moth, Plutella xylostella

Sayyed

Raymond

Ibiza-Palacios

et al. 2004

Appl Environ Microbiol

View full text Add to dashboard Cite

The long-term usefulness of Bacillus thuringiensis Cry toxins, either in sprays or in transgenic crops, may be compromised by the evolution of resistance in target insects. Managing the evolution of resistance to B. thuringiensis toxins requires extensive knowledge about the mechanisms, genetics, and ecology of resistance genes. To date, laboratory-selected populations have provided information on the diverse genetics and mechanisms of resistance to B. thuringiensis, highly resistant field populations being rare. However, the selection pressures on field and laboratory populations are very different and may produce resistance genes with distinct characteristics. In order to better understand the genetics, biochemical mechanisms, and ecology of field-evolved resistance, a diamondback moth (Plutella xylostella) field population (Karak) which had been exposed to intensive spraying with B. thuringiensis subsp. kurstaki was collected from Malaysia. We detected a very high level of resistance to Cry1Ac; high levels of resistance to B. thuringiensis subsp. kurstaki Cry1Aa, Cry1Ab, and Cry1Fa; and a moderate level of resistance to Cry1Ca. The toxicity of Cry1Ja to the Karak population was not significantly different from that to a standard laboratory population (LAB-UK). Notable features of the Karak population were that field-selected resistance to B. thuringiensis subsp. kurstaki did not decline at all in unselected populations over 11 generations in laboratory microcosm experiments and that resistance to Cry1Ac declined only threefold over the same period. This finding may be due to a lack of fitness costs expressed by resistance strains, since such costs can be environmentally dependent and may not occur under ordinary laboratory culture conditions. Alternatively, resistance in the Karak population may have been near fixation, leading to a very slow increase in heterozygosity. Reciprocal genetic crosses between Karak and LAB-UK populations indicated that resistance was autosomal and recessive. At the highest dose of Cry1Ac tested, resistance was completely recessive, while at the lowest dose, it was incompletely dominant. A direct test of monogenic inheritance based on a backcross of F 1 progeny with the Karak population suggested that resistance to Cry1Ac was controlled by a single locus. Binding studies with 125 I-labeled Cry1Ab and Cry1Ac revealed greatly reduced binding to brush border membrane vesicles prepared from this field population.

show abstract

Catalytic Mechanism of the Arylsulfatase Promiscuous Enzyme from Pseudomonas Aeruginosa

Marino

Russo

Toscano

2012

Chemistry A European J

View full text Add to dashboard Cite

To elucidate the working mechanism of the "broad substrate specificity" by the Pseudomonas aeruginosa aryl sulfatase (PAS) enzyme, we present here a full quantum chemical study performed at the density functional level. This enzyme is able to catalyze the hydrolysis of the original p-nitrophenyl-sulfate (PNPS) substrate and the promiscuous p-nitrophenyl-phosphate (PNPP) one with comparable reaction kinetics. Based on the obtained results, a multistep mechanism including activation of the nucleophile, the nucleophilic attack, and the cleavage of the S-O (P-O) bond is proposed. Regarding the phosphate monoester, the results indicate that only some steps of the promiscuous reaction are identical to those in the native process. Differences concern mainly the last step in which the His115 residue acts as a general base to accept the proton by the O atom of the FGly51 in the PNPS, whereas in PNPP, the Asp317 protonated residue works as a general acid to deliver a proton by a water molecule to the oxygen atom of the C-O bond. The shapes of the relative potential-energy surface (PES) are similar in the two examined cases but the rate-determining step is different (nucleophile attack vs. nucleophile activation). The influence of the dispersion contributions on the investigated reactions was also taken into account.

show abstract

Levels, inheritance and stability of resistance to Bacillus thuringiensis formulation in a field population of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) from Thailand

Cited by 14 publications

References 12 publications

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

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

Genetic and Biochemical Characterization of Field-Evolved Resistance to Bacillus thuringiensis Toxin Cry1Ac in the Diamondback Moth, Plutella xylostella

Catalytic Mechanism of the Arylsulfatase Promiscuous Enzyme from Pseudomonas Aeruginosa

Contact Info

Product

Resources

About