Constitutive Overexpression of Multiple Cytochrome P450 Genes Associated with Pyrethroid Resistance in <I>Helicoverpa armigera</I>

Abstract The role of cytochrome P450 monooxygenase in pyrethroid resistance was studied in different strains of the cotton bollworm, Helicoverpa armigera, from India. Filed collected strains of Nagpur and Delhi were compared to the laboratory reared population. The results showed a high resistance to deltamethrin, α-cypermethrin, and β-cyfluthrin. The results also showed that this resistance could be reduced by using piperonyl butoxide (PBO). The Nagpur and Delhi strains were found to have a 2.40 and 1.79 fold higher monooxygenase activity compared to a susceptible strain. A strong, positive correlation between monooxygenase activity and pyrethroid resistance was observed (r = 0.86 - 0.98). The relative expression of the housekeeping gene, EF-1α, and three P450 genes, was studied in the 5th instar larval midgut of the three strains. Out of the three P450 genes examined, expression of CYP6B7 mRNA was not detected in the midgut of the susceptible strain though it was highly expressed in the resistant strains. The midgut of the Nagpur strain had a 2.60 fold overexpression of CYP6B7 mRNA compared to the moderately resistant, Delhi strain. The mRNA of CYP4G8 and CYP6B2 were not overexpressed in either the Nagpur or Delhi strain. The results indicated that the elevated cytochrome P450 monooxygenase activity is associated with pyrethroid resistance in Indian strains of H. armigera, and CYP6B7 could be the P450 form responsible for pyrethroid resistance.

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Cytochrome P450 genes from Helicoverpa armigera: Expression in a pyrethroid-susceptible and -resistant strain

Insect Biochemistry and Molecular Biology ◽

10.1016/s0965-1748(97)00025-8 ◽

1997 ◽

Vol 27 (6) ◽

pp. 507-512 ◽

Cited By ~ 82

Author(s):

B Pittendrigh

Keyword(s):

Cytochrome P450 ◽

Helicoverpa Armigera ◽

Resistant Strain ◽

Cytochrome P450 Genes ◽

Helicoverpa Armígera

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Isolation and characterization of two cytochrome P450 cDNA clones for CYP6B6 and CYP6B7 from Helicoverpa armigera (Hubner): possible involvement of CYP6B7 in pyrethroid resistance

Insect Biochemistry and Molecular Biology ◽

10.1016/s0965-1748(98)00045-9 ◽

1998 ◽

Vol 28 (8) ◽

pp. 571-580 ◽

Cited By ~ 65

Author(s):

Charani Ranasinghe ◽

Andrew A Hobbs

Keyword(s):

Cytochrome P450 ◽

Helicoverpa Armigera ◽

Pyrethroid Resistance ◽

Cdna Clones ◽

Isolation And Characterization ◽

Helicoverpa Armígera ◽

Helicoverpa Armigera Hubner

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Over-expression of multiple cytochrome P450 genes in fenvalerate-resistant field strains of Helicoverpa armigera from north of China

Pesticide Biochemistry and Physiology ◽

10.1016/j.pestbp.2016.01.003 ◽

2016 ◽

Vol 132 ◽

pp. 53-58 ◽

Cited By ~ 10

Author(s):

Li Xu ◽

Dongzhi Li ◽

Jianying Qin ◽

Weisong Zhao ◽

Lihong Qiu

Keyword(s):

Cytochrome P450 ◽

Helicoverpa Armigera ◽

Over Expression ◽

Cytochrome P450 Genes ◽

Helicoverpa Armígera

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Escalation of Pyrethroid Resistance in the Malaria Vector Anopheles funestus Induces a Loss of Efficacy of Piperonyl Butoxide–Based Insecticide-Treated Nets in Mozambique

The Journal of Infectious Diseases ◽

10.1093/infdis/jiz139 ◽

2019 ◽

Vol 220 (3) ◽

pp. 467-475 ◽

Cited By ~ 16

Author(s):

Jacob M Riveron ◽

Silvie Huijben ◽

Williams Tchapga ◽

Magellan Tchouakui ◽

Murielle J Wondji ◽

...

Keyword(s):

Cytochrome P450 ◽

Pyrethroid Resistance ◽

Anopheles Funestus ◽

Resistance Mechanisms ◽

Piperonyl Butoxide ◽

Insecticide Treated Nets ◽

Molecular Analyses ◽

Cytochrome P450 Genes ◽

High Degree ◽

Long Lasting Insecticidal Nets

Abstract Background Insecticide resistance poses a serious threat to insecticide-based interventions in Africa. There is a fear that resistance escalation could jeopardize malaria control efforts. Monitoring of cases of aggravation of resistance intensity and its impact on the efficacy of control tools is crucial to predict consequences of resistance. Methods The resistance levels of an Anopheles funestus population from Palmeira, southern Mozambique, were characterized and their impact on the efficacy of various insecticide-treated nets established. Results A dramatic loss of efficacy of all long-lasting insecticidal nets (LLINs), including piperonyl butoxide (PBO)–based nets (Olyset Plus), was observed. This An. funestus population consistently (2016, 2017, and 2018) exhibited a high degree of pyrethroid resistance. Molecular analyses revealed that this resistance escalation was associated with a massive overexpression of the duplicated cytochrome P450 genes CYP6P9a and CYP6P9b, and also the fixation of the resistance CYP6P9a_R allele in this population in 2016 (100%) in contrast to 2002 (5%). However, the low recovery of susceptibility after PBO synergist assay suggests that other resistance mechanisms could be involved. Conclusions The loss of efficacy of pyrethroid-based LLINs with and without PBO is a concern for the effectiveness of insecticide-based interventions, and action should be taken to prevent the spread of such super-resistance.

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