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Resistance mechanisms to chlorpyrifos and F392W mutation frequencies in the acetylcholine esterase ace1 allele of field populations of the tobacco whitefly, Bemisia tabaci in China.

Zhang NN, Liu CF, Yang F, Dong SL, Han ZJ - J. Insect Sci. (2012)

Bottom Line: However, the resistance dropped significantly to about 18-fold in only 4 generations without selection pressure.F392W mutations in acel were prevalent in NJ-S and NJ-R strains and 6 field-collected populations of both B and Q-biotype from locations that cover a wide geographical area of China.These findings provide important information about tobacco whitefly chlorpyrifos resistance mechanisms and guidance to combat resistance and optimize use patterns of chlorpyrifos and other organophosphate and carbamate insecticides.

View Article: PubMed Central - PubMed

Affiliation: College of Plant Protection, Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, China. skyning456@163.com

ABSTRACT
The tobacco whitefly B-biotype Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a worldwide pest of many crops. In China, chlorpyrifos has been used to control this insect for many years and is still being used despite the fact that some resistance has been reported. To combat resistance and maintain good control efficiency of chlorpyrifos, it is essential to understand resistance mechanisms. A chlorpyrifos resistant tobacco whitefly strain (NJ-R) and a susceptible strain (NJ-S) were derived from a field-collected population in Nanjing, China, and the resistance mechanisms were investigated. More than 30-fold resistance was achieved after selected by chlorpyrifos for 13 generations in the laboratory. However, the resistance dropped significantly to about 18-fold in only 4 generations without selection pressure. Biochemical assays indicated that increased esterase activity was responsible for this resistance, while acetylcholine esterase, glutathione S-transferase, and microsomal-O-demethylase played little or no role. F392W mutations in acel were prevalent in NJ-S and NJ-R strains and 6 field-collected populations of both B and Q-biotype from locations that cover a wide geographical area of China. These findings provide important information about tobacco whitefly chlorpyrifos resistance mechanisms and guidance to combat resistance and optimize use patterns of chlorpyrifos and other organophosphate and carbamate insecticides.

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Related in: MedlinePlus

Resistance development of NJ-R Bemisia tabaci strain selected with chlorpyrifos in a dose of around LC70 in laboratory. LC50S were examined every two or three generations. The selection by chlorpyrifos was stopped from the 13th to 16th generation, and then restored at the 26th generation. High quality figures are available online.
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f01_01: Resistance development of NJ-R Bemisia tabaci strain selected with chlorpyrifos in a dose of around LC70 in laboratory. LC50S were examined every two or three generations. The selection by chlorpyrifos was stopped from the 13th to 16th generation, and then restored at the 26th generation. High quality figures are available online.

Mentions: To investigate the development process of the tobacco whitefly resistance to chlorpyrifos, a resistant strain (NJ-R strain) was selected from a field population in the laboratory (Figure 1). During the course of resistance selection, the LC50 increased slowly but steadily in 1st to 9th generations (from 143.90 ppm to 1458.30 ppm), and afterwards LC50 increased in a much faster pace to reach 4874.10 ppm at the 13th generation. At this point, the selection was stopped for the following four generations, and as a result, the LC50 declined sharply to about 2500 ppm measured in 17th generation. However, with additional selection the LC50 was recovered to 4818.02 ppm at the 21st generation. Continuing selection in the 21st to 26th generation did not result in increasing LC50, but maintained a value around 4800 ppm. This field collected tobacco whitefly population had a 33.94-fold chlorpyrifos resistance based on the LC50 ratio after facing selections in 22 of the 26 generations. In the meantime, from the part of the same population used for resistance selection, a relative susceptible strain (NJ-S strain) was obtained by maintaining it without exposure to any insecticide for 26 generations. These selected resistant and susceptible strains were further used to explore the resistance mechanisms.


Resistance mechanisms to chlorpyrifos and F392W mutation frequencies in the acetylcholine esterase ace1 allele of field populations of the tobacco whitefly, Bemisia tabaci in China.

Zhang NN, Liu CF, Yang F, Dong SL, Han ZJ - J. Insect Sci. (2012)

Resistance development of NJ-R Bemisia tabaci strain selected with chlorpyrifos in a dose of around LC70 in laboratory. LC50S were examined every two or three generations. The selection by chlorpyrifos was stopped from the 13th to 16th generation, and then restored at the 26th generation. High quality figures are available online.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472965&req=5

f01_01: Resistance development of NJ-R Bemisia tabaci strain selected with chlorpyrifos in a dose of around LC70 in laboratory. LC50S were examined every two or three generations. The selection by chlorpyrifos was stopped from the 13th to 16th generation, and then restored at the 26th generation. High quality figures are available online.
Mentions: To investigate the development process of the tobacco whitefly resistance to chlorpyrifos, a resistant strain (NJ-R strain) was selected from a field population in the laboratory (Figure 1). During the course of resistance selection, the LC50 increased slowly but steadily in 1st to 9th generations (from 143.90 ppm to 1458.30 ppm), and afterwards LC50 increased in a much faster pace to reach 4874.10 ppm at the 13th generation. At this point, the selection was stopped for the following four generations, and as a result, the LC50 declined sharply to about 2500 ppm measured in 17th generation. However, with additional selection the LC50 was recovered to 4818.02 ppm at the 21st generation. Continuing selection in the 21st to 26th generation did not result in increasing LC50, but maintained a value around 4800 ppm. This field collected tobacco whitefly population had a 33.94-fold chlorpyrifos resistance based on the LC50 ratio after facing selections in 22 of the 26 generations. In the meantime, from the part of the same population used for resistance selection, a relative susceptible strain (NJ-S strain) was obtained by maintaining it without exposure to any insecticide for 26 generations. These selected resistant and susceptible strains were further used to explore the resistance mechanisms.

Bottom Line: However, the resistance dropped significantly to about 18-fold in only 4 generations without selection pressure.F392W mutations in acel were prevalent in NJ-S and NJ-R strains and 6 field-collected populations of both B and Q-biotype from locations that cover a wide geographical area of China.These findings provide important information about tobacco whitefly chlorpyrifos resistance mechanisms and guidance to combat resistance and optimize use patterns of chlorpyrifos and other organophosphate and carbamate insecticides.

View Article: PubMed Central - PubMed

Affiliation: College of Plant Protection, Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing 210095, China. skyning456@163.com

ABSTRACT
The tobacco whitefly B-biotype Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a worldwide pest of many crops. In China, chlorpyrifos has been used to control this insect for many years and is still being used despite the fact that some resistance has been reported. To combat resistance and maintain good control efficiency of chlorpyrifos, it is essential to understand resistance mechanisms. A chlorpyrifos resistant tobacco whitefly strain (NJ-R) and a susceptible strain (NJ-S) were derived from a field-collected population in Nanjing, China, and the resistance mechanisms were investigated. More than 30-fold resistance was achieved after selected by chlorpyrifos for 13 generations in the laboratory. However, the resistance dropped significantly to about 18-fold in only 4 generations without selection pressure. Biochemical assays indicated that increased esterase activity was responsible for this resistance, while acetylcholine esterase, glutathione S-transferase, and microsomal-O-demethylase played little or no role. F392W mutations in acel were prevalent in NJ-S and NJ-R strains and 6 field-collected populations of both B and Q-biotype from locations that cover a wide geographical area of China. These findings provide important information about tobacco whitefly chlorpyrifos resistance mechanisms and guidance to combat resistance and optimize use patterns of chlorpyrifos and other organophosphate and carbamate insecticides.

Show MeSH
Related in: MedlinePlus