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Modulation in Activity Profiles in Insecticide-Resistant Population of Tobacco Caterpillar, Spodoptera Litura (Fabricius)


Affiliations
1 Department of Entomology, College of Agriculture, Vellayani, Thiruvananthapuram 695 522, India
2 Department of Plant Pathology, College of Agriculture, Vellayani, Thiruvananthapuram 695 522, India
3 ICAR-Central Plantation Crops Research Institute, Kayankulam 690 533, India
 

Activity spectrum of detoxification enzymes was systematically assessed in tobacco caterpillar, Spodoptera litura collected from four locations in Kerala, India, to decipher the mechanism of insecticide resistance. Using the susceptible check ICAR-NBAIR strain, specific activity profiles of acetylcholine esterase (AChE) were found to be 16.16-, 10.71- and 4.88-fold higher in the Kovilnada, Palappur and Kanjikuzhi populations respectively. Specific activities of mixed function oxidase (MFO) were also found to be 19.24-, 17.11-, 6.08-fold higher in the same populations respectively, indicating the predominance of AChE and MFO towards imparting resistance. Carboxylesterase (CarE) and glutathion-S-transferase (GST) specific activity profiles were 3.62- and 3.37-fold higher in the Kovilnada population, followed by 2.89- and 2.98-fold higher in the Palappur population and as 2.10- and 1.15-fold higher in the Kanjikuzhi population, indicating their partial role in resistance development. Suppression of specific activities in synergism bioassays with AChE in chlorpyriphos + TPP treatment (9.32-fold), GST in chlorpyriphos + DEM (4.78-fold) and CarE in quinalphos + TPP (5.15-fold) highlighted the involvement of multiple detoxification enzymes conferring resistance to organophosphates. Reduced activity of MFO in case of lambda-cyhalothrin + PBO (5.35-fold), CarE in case of cypermethrin + TPP (7.36-fold) and 3.60-fold reduction in MFO in case of cypermethrin + PBO highlighted the role of esterases and MFOs towards resistance development against synthetic pyrethroids.

Keywords

Detoxification Enzymes, Insecticide Resistance, Spodoptera litura, Synergists.
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  • Modulation in Activity Profiles in Insecticide-Resistant Population of Tobacco Caterpillar, Spodoptera Litura (Fabricius)

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Authors

P. Sreelakshmi
Department of Entomology, College of Agriculture, Vellayani, Thiruvananthapuram 695 522, India
Thomas Biju Mathew
Department of Entomology, College of Agriculture, Vellayani, Thiruvananthapuram 695 522, India
K. Umamaheswaran
Department of Plant Pathology, College of Agriculture, Vellayani, Thiruvananthapuram 695 522, India
A. Josephrajkumar
ICAR-Central Plantation Crops Research Institute, Kayankulam 690 533, India

Abstract


Activity spectrum of detoxification enzymes was systematically assessed in tobacco caterpillar, Spodoptera litura collected from four locations in Kerala, India, to decipher the mechanism of insecticide resistance. Using the susceptible check ICAR-NBAIR strain, specific activity profiles of acetylcholine esterase (AChE) were found to be 16.16-, 10.71- and 4.88-fold higher in the Kovilnada, Palappur and Kanjikuzhi populations respectively. Specific activities of mixed function oxidase (MFO) were also found to be 19.24-, 17.11-, 6.08-fold higher in the same populations respectively, indicating the predominance of AChE and MFO towards imparting resistance. Carboxylesterase (CarE) and glutathion-S-transferase (GST) specific activity profiles were 3.62- and 3.37-fold higher in the Kovilnada population, followed by 2.89- and 2.98-fold higher in the Palappur population and as 2.10- and 1.15-fold higher in the Kanjikuzhi population, indicating their partial role in resistance development. Suppression of specific activities in synergism bioassays with AChE in chlorpyriphos + TPP treatment (9.32-fold), GST in chlorpyriphos + DEM (4.78-fold) and CarE in quinalphos + TPP (5.15-fold) highlighted the involvement of multiple detoxification enzymes conferring resistance to organophosphates. Reduced activity of MFO in case of lambda-cyhalothrin + PBO (5.35-fold), CarE in case of cypermethrin + TPP (7.36-fold) and 3.60-fold reduction in MFO in case of cypermethrin + PBO highlighted the role of esterases and MFOs towards resistance development against synthetic pyrethroids.

Keywords


Detoxification Enzymes, Insecticide Resistance, Spodoptera litura, Synergists.

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DOI: https://doi.org/10.18520/cs%2Fv116%2Fi4%2F664-669