Identification of Carboxylesterase genes and their expression profiles in conferring resistance to commonly used pesticides in Zonocerus variegatus (linneaus, 1758)

T R Folorunso ,Michael Olufemi Awodiran

doi:10.33472/afjbs.3.4.2021.76-87

Abstract

Identifying insecticide resistance mechanisms is paramount for pest insect control, as the understandings that underpin insect control strategies must provide ways of detecting and managing resistance, thus study identified the ability of Carboxylesterase (CarEs) genes in conferring resistance to commonly used pesticide by examining the expression of the gene in the susceptible and resistant strain of Zonocerus variegatus, after Cypermethrin bioassay. Adult Z. variegatus was sampled from Savannah area of Oyo State, Nigeria, samples were collected and preserved in “RNA Later” for RNA extraction. The two groups of Z. variegatus were later subjected to quantitative quantitative Polymerase Chain Reaction (qPCR) using two primers. CarEs gene expressions have both negative and positive ∆∆ct value when LmcesA20 primer was used. However, no significant difference in expression level was observed between groups for both primers LmcesE9 (F = 0.84, p > 0.05) and LmcesA20 (F = 0.499, p > 0.05). The study concluded that since the expression level observed for CarEs gene was the same using LmcesE9 in both groups, LmcesE9 may not function for detoxifying Cypermethrin in Z. variegatus. LmcesA20 showed a little variation in expression level in both strains having higher fold change in resistant strain than the susceptible strain, thus these members of CarEs genes need to be further verified for their specific role in conferring resistance to use of pesticides.

Highlights

Carboxylesterases (CarEs) play significant roles in metabolism of certain hormones and detoxification of dietary and environmental xenobiotics in insects
Primers selection Electrophoresis showed B-actin to be significantly expressed than the other primers and two primers LmcesA20 and LmcesE9 were chosen from five primers selected from L. migratoria CarEs genes based on specific band showed
Comparing expression profiles in both susceptible strain and resistant strain. This present study focus on the quantitative expression profiles of CarEs genes in susceptible strain and resistant strain of Z. variegatus; the first finding, examined the expression of CarEs using different primers which varied significantly while the second finding examined the expression profiles for both the susceptible strain and the resistant strain in all the Cypermethrin concentration used, which indicate no significantly difference

Summary

Introduction

Carboxylesterases (CarEs) play significant roles in metabolism of certain hormones and detoxification of dietary and environmental xenobiotics in insects. Many insect CarEs are associated with insecticide resistance or hormone and semiochemical metabolism (Oakeshott et al, 2010; Oakeshott et al, 2013) They are involved in the detoxification of many insecticides, including synthetic pyrethroids (SPs), carbamates (CBs) and organophosphates (OPs) which. Zonocerus variegatus, (Orthoptera: Pyrgomorphidae) genus of grasshoppers (Caelifera) in the family Pyrgomorphidae (Roskov et al, 2011). It has been regarded as the main pest of food crops such as citrus, banana, cassava, cocoa, coffee, cowpea and yams in West and Central Africa’s moist lowland forest and savannas (Modder, 1994; and Kekeunou et al, 2006). By the time the first, second and third instars live on weeds such as C. odorata and Aspilia africana (Asteraceae family), the fifth and sixth instars feeds on M. esculenta (Euphorbiaceae) (Chapman et al, 1986)

Methods

Discussion

Conclusion